# Forum Home Renovation Solar Electrical Systems  Used AGM Batteries

## Window575

I've got a bank of 6x 240ah 12V batteries on a basic system that are expanding (swelling) one by one. 
The batteries were purchased used, and worked for about two months in the system, but now are going down one by one. One every couple of weeks. I estimate the batteries are atleast 6 years old, AGM's. 
When I got them, I also bought a multistage charger/conditioner and ran each of them through a charge cycle before putting them in the system. All were given the AOK.
The system doesn't get much use, every 2nd weekend only. I started with 6, now only 3 survive. I think they are all the same age. They are the same type, and all measured between 12.7-12.9 volts when conditioned. 
The system is 2x 12V 200w panels, into a 40a MPPT tracer charge controller. The MPPT is only capable of 900AH in the settings maximum. I now have only 3 batteries left in parallel.
The battery is melting the inline fuse housing (between MPPT and batteries), but not tripping the fuses. I started with 15a blade fuses. 
So my question is why do the batteries swell like this? Are they just old? Are they getting over charged? Is the controller not up to the task given it can only do max 900ah according to the settings? 
Thanks.

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## Bros

I hope you have set your controller to Gel and not sealed as it looks to me like you are overcharging the battery. Having batteries in parallel can cause some charging an discharging issues. If you parallel batteries you need to connect one supply/load to one terminal of the closest battery and the other to the furthermost battery in the set.
As for melting the fuse you have a bad joint as it is causing heating. In line fuses are notorious for that as you can get the blades to go down the side of the holder and without looking you will only have small contact area. Chuck it out and get another and when you put the fuse in pull back the cover and make sure the fuse in inside the contacts not one inside and the other leg outside.
As for battery age look on the case and you will see a set of numbers which will give you the manufacture date.  090807 – 7th of August 2009

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## Window575

Thanks Bros, very much appreciated advice. 
Found the date on the case- feb 2015! So the person I bought them off said 6 years minimum, so that's a bit weird.
I did set the charger to GEL, but I don't have the supply/load terminals at each end of the batteries, they are both linked to the 1st battery in parallel. Will fix that! The first battery just went down this last weekend, previously the end and middle batteries swelled.
Is there anything that can be down with the swollen batteries to reverse the issue?

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## Window575

The batteries are RITAR RA12-240 VRLA. I'm reading conflicting info about what setting to charge with.
The MPPT only offers SEL, GEL and FLOODED.
Is GEL definitely the one to use? 
thanks.

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## Bros

Gel

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## chrisp

If by "swelling" you mean that the battery is bulging at the ends, then this is a sign of the battery is sulphated.  This is not good. 
If the whole battery is swelling like a balloon and very hot, is is not good either and quite dangerous. 
Are you connecting these batteries in parallel? They are very large batteries to be paralleling up and a prone to problems associated with high-current and low-voltage wiring. 
If these are VRLA AGM, the controller should be set to the appropriate setting. "Gel" is too low for conventional VRLA. 
As you have been experiencing trouble with the wiring (e.g. hot fuse connections) the batteries are probably chronically undercharged and have sulphated.  There are some things you can do to try and rescue them but the odds of recovery aren't that good, but you have nothing to lose either. 
I'd be using the old batteries to get the system right before investing in replacements.

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## Bros

> If these are VRLA AGM, the controller should be set to the appropriate setting. "Gel" is too low for conventional VRLA.

   You are correct as I went and looked at the manual on the charger and the other two settings had an equalize charge that only applies to flooded batteries. Using equalize on such a small charging system will end up with it being locked in equalize mode as it will not reach the equalize voltage for the timer to start and subsequently it will be trapped between boost and equalize which will overcharge the batteries. 
 You are correct in it could be sulphation or overcharging but looking at it now I am convinced it is sulphation and he needs to seriously upgrade his charging  as the best he is going to get out of the two panels combined is 22A so he could add another 200w panel and a 150w panel and work the controller harder which should be more efficient but I still have concerns about the equalize cycle and if possible it should be taken out. Solar panels now are relatively cheap. 
 As looks like these batteries could be stuffed it could be beneficial in looking as flooded batteries as they can be more tolerant of overcharging and they are designed for remote solar power. 
Exide make them. 
Below is a link to to maintenance of Fullriver AGM batteries where parallel battery connection are shown and the take off points.  
I disagree with your reasoning for fuse overheating as I have seen this happen in inline blade fuse and they are rubbish unless you are careful with them. If he increases his solar panels normal blade fuses will be to small as the bases will not be able to carry the current.   https://www.dropbox.com/s/mihy7rs2ls...02016.pdf?dl=0

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## phild01

Just a point of interest, if an AGM won't charge up, don't consider it stuffed.  Get a good charged up battery in parallel and connect to a charger until the voltage of the flat battery is high enough to accept a charge.  Disconnect the good battery and continue charging the other. 
Also, paralleling batteries is not a good idea unless they are equal and new.

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## chrisp

> I disagree with your reasoning for fuse overheating as I have seen this happen in inline blade fuse and they are rubbish unless you are careful with them. If he increases his solar panels normal blade fuses will be to small as the bases will not be able to carry the current.

  Maybe I haven't phrased it well. I'm taking the 'hot fuse' as a symptom of poor wiring or a poor connection.  I didn't intend to infer it as a cause. 
However, the hot wiring or fuse will result in a voltage drop.  I don't know the wiring arrangements of the charging and load circuits, but as a guess, I suspect that the load is wired seperately to the panel/charge controller.  If so, the battery will not be getting sufficient charge if there is a load on it as the charge controller will be sensing the voltage on the high side of the fuse. 
The low charging or chronic undercharging, and/or chronic over-discharging is probably the cause of the sulphation. The battery bank may simply be too big for the panel, or the load too great for the panel. 
Bulging batteries are generally badly sulphated batteries and irreparablely damaged. But having said that, and depending upon the application, there is nothing to lose in attempting to recover them even if the capacity is significantly down (which it will be). 
I would suggest that the OP sort out the problems before putting new batteries in to service as there is a good chance that they will fail prematurely too.

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## Bros

> The battery bank may simply be too big for the panel, or the load too great for the panel.

  In all this that is the one thing we haven't heard about the Load. Incorrect connection of the parallel batteries will also cause some batteries to be undercharged and some over discharged.

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## Cuppa

Ritar are reasonable quality batteries & treated righter quite capable of giving 10 years+ service. As others have suggested, it does sound like they are being overcharged .  I have a smaller bank of 3 x DC120Ah Ritars & have the bulk charge voltage set as per wet batteries (14.4v). 
Blade fuses are notoriously unreliable & prone to overheating/melting in solar systems. It only takes a small sheen of oxidation on the blades for resistance to build. Circuit breakers are a safer option.  Blade fuse problems in caravans

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## Window575

Sorry for the delay getting back to you all, been away with the holiday period. 
Batteries are bulging in the middle and top, not the ends. However given the size, weight and position of batteries in the box, swelling up is the logical way they distort. 
Regarding the load, I have 2 x 15w fluro lights which I run for a few hours at night (5 hours?). A water pump (750W) which kicks in when I run the taps (max 30 mins a day total).
An iphone charger and a 15w speaker for maybe 5 hours/day. That's it. A 2000W inverter comes off the battery bank. I turn off the inverter when I leave the property, so no load during the week from it.
I did purchase a small fridge (12v/240v/LPG), but haven't used it in the system yet. As mentioned this load might happen 2 days in a fortnight. 
I used the system without these issues with 3x used AGM 12V 100ah batteries. But they would run down and not supply enough for the inverter on the second night in winter. No swelling issues with the 3 x 100ah in parallel. Or fuse issues. 
So, is this charger not up to the job? Seems to be conflicting views on the setting for battery type. 
The fuse/wire melting point seems to be at the wire connection point. The blade seating itself I don't believe is the issue. It has happened twice, replaced the holder and fuse each time. 
Thanks.

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## Window575

Given this current setup, what size circuit breaker would you recommend?

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## Bros

2000w inverter is a bloody big inverter and you sure need some battery power to drive it and keep the batteries topped up. Have you ever thought of going to 12 v on all your appliances as you can nearly run everything off 12v now days. Your 12/240/LPG would not be the best for the system as they draw up to 12 A all the time and are not very efficient, a compressor fridge is a better choice.  
The CB between the controller and batteries would be a 50 A one provided the cables are rated to that. As for the load side depends on your load and cable size but you could never accommodate that humongous inverter. 
I backed away from my Gel setting on the charger and suggest the same as for wet cell the only issue I have is the use of the equalizing charge which in AGM is not designed for AGM batteries. 
Have you looked at the link I gave which has some good info about Fullriver batteries which you can use with Ritar batteries. 
The best place to get DC circuit breakers is here   https://www.sparkydirect.com.au/c/28...-breakers.html 
or here   http://stores.ebay.com.au/On-Top-Ene..._pgn=1&_ipg=48

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## Window575

I had visions of using a coffee machine originally hence the large inverter. Then I came to my senses...
 However as it rarely gets used above 800w, I know it's big but short of the load factor not sure it's doing any harm. I don't want to replace everything yet, this was a budget setup- my first go at a weekender offgrid. As I mentioned the 3 x100ah used batt system was fine, just the batteries were very tired.
The fridge cost me $50, and the lpg option made it a no brainer. 
The cable from controller to batteries in 4mm (55A?) A 50A breaker sounds large? The max fuse I have had in there so far is 20a, a 15a did blow once I believe.
I didn't mention the fuse on the battery to inverter side is a slow burn, think it's a 200a in there but would have to check again. 
Thanks for the link to the Fullriver batts. 
I contemplated a 12v system, just not so sure of the water pump for the rainwater tank. The 750w/240v works nicely and gives me options in the future.
I'd rather get what I have got working in the short term. 
Sorry still checking for clarification on this; SEL, GEL or FLOODED setting? 
Thanks Bros.

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## Bros

> The cable from controller to batteries in 4mm (55A?) A 50A breaker sounds large? The max fuse I have had in there so far is 20a, a 15a did blow once I believe.

  I gave those figures not knowing the system. I did so in the expectation you would buy more panels to upgrade the charging system. Run another 4 mm in parallel and it will be OK.  

> I didn't mention the fuse on the battery to inverter side is a slow burn, think it's a 200a in there but would have to check again.

  Good size.    

> I contemplated a 12v system, just not so sure of the water pump for the rainwater tank. The 750w/240v works nicely and gives me options in the future.
> I'd rather get what I have got working in the short term.

  You can get good 12v pumps but they are low flow and no good for watering the garden.   

> Sorry still checking for clarification on this; SEL, GEL or FLOODED setting?

  For your controller the only option is SEL as gel is to low but flooded would be OK but it has that equalize function that is best to avoid. So Sealed it is as the equalize voltage is only 0.2v above boost where flooded equalize is 1 volt above the boost voltage for sealed.

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## Window575

Really appreciated Bros-thank you, and happy new year. 
Garden watering is high on my list of priorities at the bush block, and it's why I chose the tank/pump combo I've got. You're on the money there. 
Will modify things this week, wiring and circuit breaker and check back in the near future. 
cheers.

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## Cuppa

4mm cable most certainly does not sound large to me, & is almost certainly too small & getting hot.  Forget the 'amp rating' for cable in low voltage situations & instead look at the size of the cross section of copper in sq.mm.  If you have a look at the chart in the following link you will see recommended cable sizes for solar. You will see that cable size depends upon both the current it has to carry AND how far it has to carry it. The thinner the cable & the further it has to carry it the greater the losses (to heat).  You can translate the cable size requirements your system needs from the table.  I think you may be surprised at what you need.   Motorhome and Caravan Info Australia Â» Blog Archive Â» Calculating the cable size for wiring solar panels 
Note also there is cable & cable. 4mm sq copper is just that. 4mm auto cable is probably no more than about 1.6mm copper (the insulation is counted as part of the size with auto cable).

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## Bros

> Note also there is cable & cable. 4mm sq copper is just that. 4mm auto cable is probably no more than about 1.6mm copper (the insulation is counted as part of the size with auto cable).

  Good point, I was assuming real 4mm not the fake stuff.

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## Window575

So many variables.
The 4mm in question has never even been remotely 'warm'. When I was setting up the system I questioned this part of the system the most, as given the cable sizes I was using at the back end, this looked tiny by comparison. Am I showing my ignorance here? :Smilie: 
I will measure it with my calipers though. Bought as solar wire when setting up the system, not auto stuff. About 4mm wire not including insulation, but will check. 
Ta.

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## Cuppa

Check the link I posted. 
At 12v a 4mm2 cable is good for carrying up to about 24 amps over 2 metres or 15 amps over 3 metres, or 8 amps over 6 metres.  
What is the cable distance between your regulator & the batteries?    Your panels are probably capapable of generating something between 20 & 25 amps.  
As said thin cable/long runs results in current losses/voltage drop. You would not necessarily have cables which feel warm to the touch, but the loss in efficiency (less amps getting to the batteries) means the available charge is going somewhere else other than to the batteries. This is where heat comes into the equation.   I am not suggesting this heat to be the cause of the problems you have experienced with melting fuses & expanding batteries. That is almost certainly occurring due to high resistance connections & overcharging respectively.  
If the charge setting on your regulator is set to the appropriate setting for you batteries then it is quite possible that your regulator is faulty. Batteries don't swell of their own accord. Overcharged AGM batteries can go into 'thermal runaway, where the voltage goes into an ever increasing rise. This can make batteries swell, or even catch fire. For that reason you would be wise not to leave them connected in your absence until you get to the bottom of what is happening. I'm not sure but would wonder if the voltage is rising due to overcharging/ thermal runaway whether this is also causing the fuse issue. I'm guessing that if you had a circuit breaker rated the same as the fuse that it would disconnect in the circumstances. Likewise a good quality fuse (not a blade fuse) would likely blow. Either would just be an indicator that there is a problem. The melting fuse holder indicates the same, but is also a problem as it represents a fire hazard in it's own right.

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## chrisp

> ....
> Regarding the load, I have 2 x 15w fluro lights which I run for a few hours at night (5 hours?). A water pump (750W) which kicks in when I run the taps (max 30 mins a day total).
> An iphone charger and a 15w speaker for maybe 5 hours/day. That's it. A 2000W inverter comes off the battery bank. I turn off the inverter when I leave the property, so no load during the week from it.
> I did purchase a small fridge (12v/240v/LPG), but haven't used it in the system yet. As mentioned this load might happen 2 days in a fortnight.

  With battery energy storage systems, it is usually easier to work in Ah rather than W. 
Going through your lists of loads (and taking the Wattages at face value) and working out the daily energy requirements: 
Lighting: 2.5A for 5h = 12.5 Ah
Pump: 62.5A for 0.5 hr = 31.25 Ah
Phone and speaker: 0.5A for 5 h = 2.5Ah 
The daily energy requirements are roughly 46.25 Ah, let's call it 50Ah to simplify typing. 
If this was used daily, you'd need a system that can store 50Ah and a solar panel (or whatever charger you are using) to be able to replenish the 50Ah each day.  Your battery system is truely big enough and in my opinion it is oversized.  Your solar system is also well and truely large enough. 
As thus is a holidayer, and only used 2 days out of 14, you can use a fortnightly calculation rather than a daily calculation. 
Over a fortnight, the load is 100Ah (i.e. 2 days).  If you choose to use a smaller charger on the assumption that it can be used to recharge the pack over 14 days, you need to ensure that it can deliver 100Ah/14day = 7.2 Ah on average each day.  You will need to ensure that the battery pack has a useable storage capacity of 100Ah.  This needs to be 'derated' as you will shorten the life of a battery using it at 100% depth of discharge (DoD).  Try and keep it to less than 50% with new batteries to allow a little head room. 
As a rough ballpark guide, I would suggest:   Battery pack: ~200Ah (or use one 240Ah that you already have)Solar panel that can deliver 2A for 4 hours a day.  (You have this well covered, but make sure that the "12V" panel can truely deliver 14.4V to 14.7V after the regulator.  This will usually require 16V-plus from the panel.Retain your inverter. Hopefully, it is a type that will completely shutdown when the load is below a threshold?Fix up your wiring. Voltage drop in low-voltage systems is very problematic.  
Monitor the battery voltage with a multimeter.  You need to be seeing something like 14.4V when charging is near complete.  If you are only getting 12V or so, the battery won't be recharging correctly and will be poorly equalised and will prematurely fail. 
Note, if the batteries are very flat (below 10V), they will be in a high-resistance state and they won't accept charge very well.  You can usually spot these as the voltage will quickly jump to the top-of-charge-voltage but they won't draw much current from the charger. They can give the impression of being charged when they are empty!  If you suspect this, leave them on the charger for a while and you should see the voltage drop as they charge (and then begin to slowly rise again).

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## Bros

I believe he should go bigger on the solar side as energy consumption seems to grow over time. I have a friend who has a holiday house and he seems to be adding more solar and more batteries over time. Remember he said garden watering gets done as well as household uses so that on its own adds more demand.

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## Window575

Thanks Cuppa and Chrisp.
Fire hazard has been my main concern, especially in the bush. I'm available more in the 'holiday' month and will monitor it more. I've been turning the whole system off since the second battery went down.
The cable run from the panels to the mppt about 6 metres, the mppt to the batteries about 60cm's with the blade fuses on each line to the batteries, both 4mm cable. But both cables are going to the 1st battery as mentioned in an earlier post, will change to the 1st and last. 
Sorry I thought I posted this, but it's not showing up.
I think the minimum voltage I've ever read (with a multimeter) was 11.3V. I've never got anything like 14.4V though either. Even when using the conditioner before putting in the system. All 6 were between 12.7V-12.9V.
 I also have another/smaller 30a mppt charger of the same brand which I can switch out. One step at a time though me thinks.

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## Window575

I wanted a system I could upgrade and kept that in mind even with this modest setup. That's why I bought the 2000w inverter. But panels are clearly more important it seems.
Looking from the wrong end maybe :Smilie: 
FYI panels, mppt, cable and inverter were new. Batteries 2nd hand.

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## chrisp

Can you post some pictures of the batteries and the wiring in general?  The forum members can pick up a lot of info from pictures. 
Also, as others have mentioned, thermal runaway is a possibility here.  A picture might help us identify this.  Old batteries, and batteries of particular brands can be more susceptible than others to thermal runaway.  Very hot batteries is a sure sign that something is not right. 
I would strongly suggest closely supervising the operation of the system until you are fully confident that it is operating  correctly.

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## Bros

> I wanted a system I could upgrade and kept that in mind even with this modest setup. That's why I bought the 2000w inverter. But panels are clearly more important it seems.
> Looking from the wrong end maybe
> FYI panels, mppt, cable and inverter were new. Batteries 2nd hand.

  The only reason I said more panels is they are cheap and today it might be a good day and tomorrow not so good as far as sun is concerned and you have the regulator capacity. The voltage you quote can be rubbery as you can see a lot of charts on the net of voltage vs capacity and no two are the same the only thing they can agree on is where flat is. 
In my shed I have a 200Ah AGM battery I got on the SH cheap 10 years ago and it is stuffed. I use it to winch my caravan into my shed and I have to put the charger on it when I want to use the winch If I charge it with my 6A Ctek charger is quickly goes to half charge then after 4 hrs it is full and the charger cuts off. 
You can systematically go through your batteries and get an accurate check of your battery capacity. 
To do this get two 50 w globes from Super creep solder a couple of wired on the back of each so you have to separate loads. Charge the batteries to capacity and switch off the charger. Before you go to bed connect up the two lights and a voltmeter one battery and let it go. Time when you start and when the battery gets to 10.5v and the load x time will give you the Ah capacity of the batteries. The aim is to discharge the batteries in around 20 hrs.  
If the batteries are good immediately recharge.

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## Window575

I'm going to the property tomorrow, will get some pictures and post online happily. 
I knew I needed more panels, probably regret going with a 12v system as 2nd hand is harder to source panels it seems.
As a cameraman I have 100w bulbs a plenty! Can easily do a test if needed.
I also have a second shed which will need some basic solar soon, so the old batteries are already planned for it.
The conditioner/charger I got is Ctek also. Unfortunately there is no mains power at the property though. So any battery conditioning means lugging the 80kg battery back to Sydney. Times 3 :Smilie:

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## Bros

> The conditioner/charger I got is Ctek also. Unfortunately there is no mains power at the property though. So any battery conditioning means lugging the 80kg battery back to Sydney. Times 3

   I can't see anyway around it as you need to find the battery capacity. I hope the 100w lamps are 12v incandescent. Anyhow it will keep you off the streets.

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## Window575

For sure, was just whinging. 100w/12v's I've got. And I need to be kept busy..
Ta.

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## Cuppa

> I think the minimum voltage I've ever read (with a multimeter) was 11.3V. I've never got anything like 14.4V though either. Even when using the conditioner before putting in the system. All 6 were between 12.7V-12.9V.

  Based on those voltages, which sound far from healthy, (dependent upon when they were measured) I have another hypothesis about the swelling batteries. 
If correct, I would suggest that some, or all, the batteries are 'stuffed'.  In a single battery if a cell in a battery has gone bad the charger/regulator will read the battery as 'low' & continue trying to charge it. Result is the remainng cells get overcharged, get hot & cause the case to swell.  
Alternatively if one battery within a bank of batteries is no longer able to be charged properly this can cause the other batteries in the bank to be overcharged, similar to a single battery with a bad cell.  
I suggest that the first thing you need to do is to ascertain the health of your batteries, without first doing this any other checking will be unreliable.  
To check them you will need to separate the battery bank & charge each battery individually on a mains charger, preferably a multi stage charger with a float mode. 
First thing will be to see if each battery is capable of reaching 'float'.
Second, once float is reached, disconnect the battery & let it sit unconnected for an hour or so & then measure the voltage across the terminals. If healthy you should expect a reading of 12.6v or higher. 
Third you need to do a load test with something like a 60w headlight globe. Connect it & leave it on for 30 minutes or so. This will draw around 2.5 Ah. The voltage will drop whilst the load is connected, perhaps by 0.2 or 0.3v, if it drops down to 12v or less the battery is cactus. Once disconnected should in a healthy battery rise slowly again, so after having let the battery stand disconnected again, for a minimum of 30 minutes, more is ok, & again check the voltage across the terminals. Voltage should be back up to what it was prior to connecting the load, or at least to within 0.1v of it.  
It's a time consuming process doing this with each battery, but is the only way you can check if the batteries are healthy or junk. Doing anything else is chasing your tail.  
Regarding your cable size from regulator to batteries - sounds ok, but would want upgrading if you increase your solar input in the future. 
Regarding efficiency the cable between panels & regulator needs to be 6 B&S (13 Sq.mm copper) - & will need increasing if you substantially increase solar input.  
Regarding increasing solar input, I agree with others you will probably want to do this, but it's not the cause of your problems, & I think you would be wise to get those sorted first.  
Hope this helps.

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## Window575

When I got the batteries earlier this year (2016) I did a charge, condition and load test on each and they all read above 12.7v. They all reached float mode on the charger. I have a load tester.
Depending on how I go today, might bring them home to go through again.
Thanks.

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## Bros

I don't know how good load testers are with batteries with reduced capacity as to weather they would tell you the exact capacity of the battery. On a discharge test that I have outlined they may come up as 100Ah and could be suitable for other uses. You said you have another system to use them on but you should know the capacity of them. If you find they are only 50 Ah well the dump is the only place for them.
If they came up as 100AH I would not parallel them with a new 100Ah battery best to keep same size, type and age for paralleling.

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## Cuppa

Bros is on the money.

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## ringtail

> If you parallel batteries you need to connect one supply/load to one terminal of the closest battery and the other to the furthermost battery in the set.

  Can you expand on this Bros ? I'm just about to put two extra batteries in my ute and have struck this advice before on a few other forums. I've consulted 2 auto sparkies and 2 electronics techs and all of them say it's rubbish and makes absolutely no difference at all.

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## Bros

> Can you expand on this Bros ? I'm just about to put two extra batteries in my ute and have struck this advice before on a few other forums. I've consulted 2 auto sparkies and 2 electronics techs and all of them say it's rubbish and makes absolutely no difference at all.

   I doubt it would make a lot of difference in a vehicle as the charging system is pretty rough and they don't take a battery to 100% unlike a solar system where you want the batteries at maximum. Solar systems have a better charging system and can fully charge batteries. 
Fullriver make batteries and have a good idea of how to connect batteries so check out my link at post 7. 
My caravan batteries are cross connected as it is supplied by a good multi stage charger and solar. My vehicle is just parallel.

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## ringtail

Cool. On that note there is also the ongoing debate of VSR's vs dc-dc chargers. But that's for another thread I guess. My farm solar uses a 20 amp mppt controller, 1x 250 watt household panel with 37ish OCV and 1x 150 ah ac delco semi cycle calcium battery. Works awesome. The most I've seen it pump out was 15 v and 14.8 amps. Ahhh the beauty of mppt controllers.

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## Cuppa

I have the batteries (3 x 120AH AGM's) in my camper connected in the No.3  pattern in this link. SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
Whether it makes any difference to battery life is something for folk to enjoy a good argument about, but it did help in making the installation a bit neater.

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## chrisp

> I have the batteries (3 x 120AH AGM's) in my camper connected in the No.3  pattern in this link. SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
> Whether it makes any difference to battery life is something for folk to enjoy a good argument about, but it did help in making the installation a bit neater.

  I like the link.   :2thumbsup:

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## ringtail

Awesome link Cuppa. Exactly what I was after. Oh Bros, your link wont work for me. I even tried to download direct from the website but my putes had a hissy fit about it.

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## Bros

Try this  https://www.wholesalesolar.com/cms/f...3495271541.pdf

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## ringtail

> I have the batteries (3 x 120AH AGM's) in my camper connected in the No.3  pattern in this link. SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
> Whether it makes any difference to battery life is something for folk to enjoy a good argument about, but it did help in making the installation a bit neater.

  I guess doing any installation using the correct methods will be difficult in the ute. 2 batteries in the tray ( one either side) and the cranking battery at the front. Some mighty long cable runs. Although using method 3 I could run the cables to a central  point of equal distance or close enough but make the cable lengths exact.

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## Bros

> I guess doing any installation using the correct methods will be difficult in the ute. 2 batteries in the tray ( one either side) and the cranking battery at the front. Some mighty long cable runs. Although using method 3 I could run the cables to a central  point of equal distance or close enough but make the cable lengths exact.

   Is it worth it in a ute?

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## Cuppa

Mine are in a ute, albeit with the camper batteries inside the rear canopy.  
The default charging is via solar or dc to dc charger, but with the possibility of paralleling them directly with the crank battery in the engine compartment (manual switch of the type which ensures the alternator is protected if switched with the motor running) ......  
This allows extra capacity for winching purposes as well as the possibility for faster bulk charging should the camper batteries ever get severely discharged & a means of getting some charge into the camper batteries were the combined dc to dc charger/solar regulator to fail a long way from anywhere.  
A mains charger can also be used to charge all batteries together id desired. Because of the current draw when winching the connecting cable had to be pretty heavy, but cable flexibility & routing options were a constraint, so 70mm2 was the best compromise.  
Although it is quite possible that under full noise the winch can be pulling between 450A & 500A, the fuse (megafuse) is rated at 225A. Initially I had a 450A fuse, but later understood that the nature of a slow blow fuse & the intermittent load used during winching allowed for a lower rated fuse giving a greater safety factor.

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## phild01

Like the Tvan!

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## ringtail

> Is it worth it in a ute?

  What do you mean ? Dmax, canopy, draws, winch, fridge, farm, cape, kimberly etc....

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## Bros

> Mine are in a ute, albeit with the camper batteries inside the rear canopy.

  I like it, certainly a lot of thought and money went into that setup but as you are trying to maximize your energy storage levels. With your setup you obviously go to real remote camping where you need to be self sufficient. This setup would be prohibitive and expensive to the great unwashed who just wanted a dual battery to run the beer fridge on weekend trip with the vehicle running every day. Their system would just require a VSR and second battery. 
The system I have on my caravan is 2 x 120 solar 2 x 105 Ah batteries which with our use is overkill but I can also parallel up the ute aux battery to take advantage of the excess storage and charging I have in the van.

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## ringtail

Here's a interesting conversation re fuse sizes and why it makes no sense in heavy cable runs.  View topic - what's the difference between dual battery kits?? | Australian 4WD Action

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## Bros

> What do you mean ? Dmax, canopy, draws, winch, fridge, farm, cape, kimberly etc....

  Huh??

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## ringtail

One still only requires a smart VSR for hard core remote touring. Some sort of aux charging device either genny or solar for when the vehicle is switched off.

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## ringtail

> Huh??

  Your comment, "is it worth it in a ute" .  
Why would it not be "worth it" in a ute ? A ute is as worthy a recipient as a caravan, camper trailer, boat etc.....

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## Bros

> Dmax, canopy, draws, winch, fridge, farm, cape, kimberly etc....

  Doesn't make sense

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## Bros

> Although using method 3 I could run the cables to a central  point of equal distance or close enough but make the cable lengths exact.

  This is what you were think of so I said is it worth it to go to that much trouble for ute rather than just ordinary parallel especially if you use a VSR.

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## Cuppa

> One still only requires a smart VSR for hard core remote touring. Some sort of aux charging device either genny or solar for when the vehicle is switched off.

  
From my perspective the choice between a VSR or a dc to dc charger is one which is best determined by two things.  1. distance of the batteries being charged from the crank battery & 2. Pattern of usage.  
I have used both & find that because most of the time I dont discharge our battery capacity below about 70% (giving longer battery life as well as having sufficient 'buffer' capacity to last a week to 10 days of poor solar weather without needing to drive) that the dc to dc charger now works best for us.   In the past we had a VSR (2 way Redarc SBI24D) which we used to charge house batteries in our bus together with roof mounted solar to top them up to 100% from what the alternator was able to put into them (about 80%).  
Both systems work well. 
Both systems work better than a VSR alone (no solar).
The limiting factor of the dc to dc is (in my case) being restricted to a max charge of 40A. This is why one reason I built in the ability to bypass the dc to dc, allowing the 70A alternator to charge at a faster rate if required up to around 80% capacity.  
Distance of batteries from the crank battery is not really an issue in my case as voltage drop is not an issue with the 70mm2 cable, but for most folk who use thinner cable with a longer run to, for example a caravan or camper trailer mounted battery, a dc to dc charger compensates for voltage drop which would occur with many VSR setups. 
EDIT: Oh, & another reason for using the dc to dc this time around was my 'Scottish heritage'.  :Wink:  Using a combined dc to dc/solar reg was cheaper than using a VSR & separate solar reg.

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## ringtail

> Doesn't make sense

  Thought you were implying that a humble ute is not worthy of additional batteries  :Biggrin:

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## ringtail

> From my perspective the choice between a VSR or a dc to dc charger is one which is best determined by two things.  1. distance of the batteries being charged from the crank battery & 2. Pattern of usage.  
> I have used both & find that because most of the time I dont discharge our battery capacity below about 70% (giving longer battery life as well as having sufficient 'buffer' capacity to last a week to 10 days of poor solar weather without needing to drive) that the dc to dc charger now works best for us.   In the past we had a VSR (2 way Redarc SBI24D) which we used to charge house batteries in our bus together with roof mounted solar to top them up to 100% from what the alternator was able to put into them (about 80%).  
> Both systems work well. 
> Both systems work better than a VSR alone (no solar).
> The limiting factor of the dc to dc is (in my case) being restricted to a max charge of 40A. This is why one reason I built in the ability to bypass the dc to dc, allowing the 70A alternator to charge at a faster rate if required up to around 80% capacity.  
> Distance of batteries from the crank battery is not really an issue in my case as voltage drop is not an issue with the 70mm2 cable, but for most folk who use thinner cable with a longer run to, for example a caravan or camper trailer mounted battery, a dc to dc charger compensates for voltage drop which would occur with many VSR setups. 
> EDIT: Oh, & another reason for using the dc to dc this time around was my 'Scottish heritage'.  Using a combined dc to dc/solar reg was cheaper than using a VSR & separate solar reg.

  
ahhh the old dc-dc vs VSR is raising it's head  :Biggrin:  . One still needs the drive time with a dc-dc for it to be effective as opposed to using the alternator

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## ringtail

The OP better post some bloody photos before this thread explodes. Still on topic though, I guess  :Biggrin:

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## Bros

> Thought you were implying that a humble ute is not worthy of additional batteries

  No

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## Cuppa

> ahhh the old dc-dc vs VSR is raising it's head  .

  Not really, there is a place for both, particularly if solar is involved too.  The reason I mentioned that I don't tend to take my batteries below 70%  is because used like that the dc to dc spends it's time topping up the batteries to 100% . Thus within a relatively short driving time I can arrive at my next camp & have the batteries fully charged, something that an alternator alone & driving all day cannot achieve. 
So the issue is not dc- dc vs VSR, but rather smart (multi stage) charging vs 'dumb' charging, something a VSR with added solar (solar reg being a smart charger) or a dc to dc charger both do better than the alternator can achieve.  
Usage pattern is everything. If a VSR alone meets someone's needs, & the simplicity & lower cost of installation compensates for shorter battery life making that choice is both valid & sensible.

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## ringtail

Agree. Pattern of usage and load sharing from a large battery bank is key. There are VSR's out there that allow a back charge of the battery bank via solar, dc-dc etc...and that's the way I'll be going. VSR with solar and mppt.

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## phild01

So, can the VSR, MPPT and a Ctek DC-DC charger be all parallel-ed to the aux battery without any additional relays.  So when voltage drop stops charging from the alternator, then the DC-DC carries on, all the while solar doing it's bit through the MPPT. (I had a MPPT until it failed!)

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## Cuppa

> There are VSR's out there that allow a back charge of the battery bank via solar,

  Yep, the two way 'D' (for Dual) model Redarc VSR I mentioned previously that we had in our bus is just that & it worked well. With the batteries paralleled with the crank battery via this type of VSR there is a small added bonus which can be utilised. On a sunny day with both camper & crank batteries fully charged the threshold voltage at which the VSR disconnects the two batteries is lower than the fully charged crank battery, thus giving a little extra capacity for camper use. However assuming the crank battery is a wet battery, if that 'little extra' isn't used within a short time of the sun going down the wet battery voltage drops a little & drags the camper battery voltage down with it until the VSR reaches separation voltage. Swings & roundabouts .... not remotely an issue of concern, just one of interest.   
On MPPT, I have mixed feelings. There are way more regs out there which are marketed as MPPT where the letters printed on the case are about all that differentiates them from a standard PWM reg. A good quality MPPT reg is worth having, but such a thing is not available for under several hundred dollars. If not wishing to spend that much a reasonable PWM reg is just as good if not better. Personally if I had to choose between MPPT & temperature compensation (with battery mounted sensor)  I'd go for temperature compensation every time. Having installed the Redarc BCDC 1240 (which is MPPT) my biggest regret is that it doesn't have this.  As a solar reg my previous Morningstar Tristar (PWM) was far superior. The two Fullriver DC150's it is connected to were still going strong last I heard & were then 10.5 years old. 
A mate who had a top of the range Blue Sky MPPT reg & travelled for 3 years overland to the UK & back found the MPPT of far more benefit in the Northern hemisphere than in Australia. Unfortunately despite it's good reputation & high cost it karked it somewhere in one of the 'Stans.

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## Cuppa

> So, can the VSR, MPPT and a Ctek DC-DC charger be all parallel-ed to the aux battery without any additional relays.  So when voltage drop stops charging from the alternator, then the DC-DC carries on, all the while solar doing it's bit through the MPPT. (I had a MPPT until it failed!)

  If you use a dc to dc charger, it also has the function of a VSR to protect the the crank battery from over discharge, so a VSR is superfluous.  
 I'm not 100% certain, but believe the Ctek Dual dc/dc can be used as a combined solar reg & dc -dc, & possibly allows fixed solar & alternator to both work concurrently, (although I see no benefit with this, & potentially it could make any fault finding more difficult I'd have thought) With the Redarc BCDC1240 an additional relay is required if auto switching between alternator & solar is desired. It either solar or dc -dc. This is what I have. Start the motor & charge is dc -dc. As soon as ignition is turned off solar kicks in (in daylight hours of course  :Smilie:  ) 
With a two way VSR & separate solar reg (no dc-dc) there is no problem having solar & alternator charging at the same time, but no benefit other than not having to be concerned about the two sources somehow battling it out!  :Biggrin:

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## phild01

> If you use a dc to dc charger, it also has the function of a VSR to protect the the crank battery from over discharge, so a VSR is superfluous.  
> I'm not 100% certain, but believe the Ctek Dual dc/dc can be used as a combined solar reg & dc -dc, & possibly allows fixed solar & alternator to both work concurrently,

  What I mean is that the DC-DC has a current limit and more amps can be delivered by the VSR, or isolating relay, until such time as voltage drop inhibits further charging.  The DC-DC charger can then carry on! 
Yes,  my Ctek facilitates solar as well.

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## Bros

> The limiting factor of the dc to dc is (in my case) being restricted to a max charge of 40A. This is why one reason I built in the ability to bypass the dc to dc, allowing the 70A alternator to charge at a faster rate if required up to around 80% capacity. 
> .

  I would think that would be useless as the VSR only bring the Aux battery in parallel and the ability of charging over 40A would be questionable unless you disconnected the main battery and the alternator is them only feeding the Aux battery. A DC DC charger is better value.

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## Cuppa

> I would think that would be useless as the VSR only bring the Aux battery in parallel and the ability of charging over 40A would be questionable unless you disconnected the main battery and the alternator is them only feeding the Aux battery. A DC DC charger is better value.

  I don't have a VSR.
However, yes my manual switch would parallel the Aux & crank which the alternator then 'sees' as one large battery. How much of the alternator's full output would 'flow' in those circumstances would depend upon the level of charge in the battery. I'm not sure why you think that this would not be over 40 amps. If the batteries were charged enough that they could only  take 40 amps or less (the usual situation) I wouldn't bother to parallel them as  the dc to dc would indeed better charge the aux batteries. One of my earlier posts mentioned other advantages to being able to bypass the dc to dc charger.

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## phild01

> I don't have a VSR.
> However, yes my manual switch would parallel the Aux & crank which the alternator then 'sees' as one large battery. How much of the alternator's full output would 'flow' in those circumstances would depend upon the level of charge in the battery. I'm not sure why you think that this would not be over 40 amps. If the batteries were charged enough that they could only  take 40 amps or less (the usual situation) I wouldn't bother to parallel them as  the dc to dc would indeed better charge the aux batteries. One of my earlier posts mentioned other advantages to being able to bypass the dc to dc charger.

  In answer to my previous question, is your DC-DC simultaneously working with direct alternator output to the aux batteries?

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## Cuppa

> In answer to my previous question, is your DC-DC simultaneously working with direct alternator output to the aux batteries?

  If you're asking if the dc-dc charger is connected directly to the alternator..... no, I've never heard of anyone doing that. If you wanted to do that I think you'd probably buy a smart alternator regulator. 
Alternator charges the crank battery & the crank battery is connected to aux batteries via the dc -dc charger  - see the wiring diagram I posted earlier.

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## ringtail

Grrrr. I can't for the life of me find the particular VSR I was going to use. It's made by some guy on the Sunshine or Gold coast. A rather opinionated chap too. Oh well, keep searching

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## phild01

> If you're asking if the dc-dc charger is connected directly to the alternator..... no, I've never heard of anyone doing that. If you wanted to do that I think you'd probably buy a smart alternator regulator. 
> Alternator charges the crank battery & the crank battery is connected to aux batteries via the dc -dc charger  - see the wiring diagram I posted earlier.

  No, My Ctek has direct connection to the starting battery which is for all intents, direct to the alternator.  
So, what I am wondering, big wire from the start battery to both the dc-dc and the aux battery, whilst dc-dc is also connected to aux battery.  Thus big amps to low level aux battery by direct connection, and as voltage rises on the aux battery, the dc-dc keeps topping it up. 
I did glance at the diagram earlier but it was a bit fuzzy, and wasn't sure what was what and the extra relays.  Will look again .   _Edit:  looking again, the schematic seems to show direct alternator charging OR dc-dc charging, as opposed to what I am interested in, being direct alternator AND dc-dc charging._

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## Bros

> I don't have a VSR.
> However, yes my manual switch would parallel the Aux & crank which the alternator then 'sees' as one large battery. How much of the alternator's full output would 'flow' in those circumstances would depend upon the level of charge in the battery. I'm not sure why you think that this would not be over 40 amps. If the batteries were charged enough that they could only  take 40 amps or less (the usual situation) I wouldn't bother to parallel them as  the dc to dc would indeed better charge the aux batteries. One of my earlier posts mentioned other advantages to being able to bypass the dc to dc charger.

  I got confused between your old and new. As for parallel tow batteries one fully charged and one half charged I have doubts weather you can fully utilize the alternator output. Saying that I have not see evidence on way or the other as you would have to measure current flows in each battery.

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## Cuppa

> I got confused between your old and new. As for parallel tow batteries one fully charged and one half charged I have doubts weather you can fully utilize the alternator output. Saying that I have not see evidence on way or the other as you would have to measure current flows in each battery.

  My understanding is that when you parallel batteries that are at different levels of charge they will equalise their voltage over a fairly short period of time. Once equalised the alternator will be charging them all as one larger battery & the amount of current accepted is then just a function of level of charge, no different to a single battery.

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## phild01

Looking again, the schematic seems to show direct alternator charging* OR* dc-dc charging, as opposed to what I am interested in, being direct alternator* AND* dc-dc charging.

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## Cuppa

> Looking again, the schematic seems to show direct alternator charging* OR* dc-dc charging, as opposed to what I am interested in, being direct alternator* AND* dc-dc charging.

  Correct.  
I'm don't think you can do what you want.  I suppose you are wanting to increase bulk charge current whilst retaining the smart charging to 'top up'?  If I were to use direct charging I would monitor the aux battery voltage on the driving cab monitor & when I judged the reading equated to around 70% charged, I'd switch over to dc-dc.

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## phild01

> Correct.  
> I'm don't think you can do what you want.  I suppose you are wanting to increase bulk charge current whilst retaining the smart charging to 'top up'?  If I were to use direct charging I would monitor the aux battery voltage on the driving cab monitor & when I judged the reading equated to around 70% charged, I'd switch over to dc-dc.

   :2thumbsup:   
 Won't the voltage readout just display charging voltage of more than 14V, regardless, or does the switch disable any charging? 
Edit: Ok, the switch is 3 way, the rest is a bit fuzzy.
  But it would be a bit of a hunch how charged the batteries are with such short term disablement.

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## Cuppa

> Won't the voltage readout just display charging voltage of more than 14V, regardless, or does the switch disable any charging? 
> Edit: Ok, the switch is 3 way, the rest is a bit fuzzy.
>   But it would be a bit of a hunch how charged the batteries are with such short term disablement.

  There are two switches, although only one is relevant to our discussion. 
The irrelevant one was a protective measure. My battery monitor can only handle up to 100 amps & I was concerned that if I used the winch & drew a lot more than that that potentially it could fry the battery monitor, so ended up putting in the switch (Switch 'Y') which effectively took the monitor out of the circuit, My thinking was that after winch use I would have to bring the batteries back to float voltage & then reset the monitor. As it is the monitor seems to be capable of surviving so the switch was unnecessary . 
The main switch (Switch 'X') only switches between either paralleled or dc -dc.  When the switch is in the off position between the two, if the engine is not running the batteries are getting solar charge.  If the engine is running with the with the switch in the off postion then no charging is occurring.  The relay which switches between solar & dc-dc is controlled by the ignition switch.  If I switch to parallel without the engine running both aux & crank battery are solar charged.  
You're right.
I haven't had the aux batteries low enough to test what voltage readings I'd get from 'direct' alternator charging. My expectation is that intially the reading would be lower than 14.4v, but would rise to this fairly quickly. It would sit at this for a predetermined period of time (can't recall how long), & I could then monitor the state of charge on the battery monitor.  When travelling in the vehicle full time one builds a familiarity with the operation of the system so i would expect to be able to make a judgement as to how long I might be best to leave it switched to parallel before switching back to dc-dc.  Hmmm, then again perhaps I wont build familiarity as it's a function I hope not to need very often - only likely in circumstances such as having been camped wthout driving for a period of poor solar weather followed by getting bogged & needing to winch whilst the batteries were fairly low. At that point getting some charge back into the batteries as quickly as possible would be the objective, getting them back up to float could wait for another sunny day.

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## ringtail

This is the VSR I was thinking of getting. The only difference between it and others that I can see is it seems to leave the batteries coupled until 12 v is seen at the cranker rather than 12.8. His reasoning is that it's better to be drawing from 2 or 3 batteries limiting overall discharge which then supports his claim (according to him) that the alternator will recharge way faster than any dcdc could ever hope to for a given amount of drive time. He also claims that it's only calcium/calcium batteries that require over 14.5 to reach 100% SOC (which is true) so any battery will charge to pretty much 100% with 13.2+ . He is fiesty and defends his product ( he makes it) on various forums with gusto. You can click on "isolators" to see his full range. The other feature of his gear is the output can be split or coupled.  SC80 - 90 amps Standard Isolator | TRAXIDE - RV | Traxide - RV

----------


## phild01

> that the alternator will recharge way faster than any dcdc could ever hope to for a given amount of drive time. He also claims that it's only calcium/calcium batteries that require over 14.5 to reach 100% SOC (which is true) so any battery will charge to pretty much 100% with 13.2+ .

  All assuming big fat cables, and is where dc-dc chargers come into their own.
I would like to see more data suggesting 13.2 is enough to bring AGM to 100%!

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## ringtail

He reckons he has done the research over 20+ years of R&D etc..... And big fat cables are mandatory as far as I'm concerned in any installation. Bigger is always better, always. 6B&S is the bare minimum IMO. I scored a 30mt roll of marine (tinned) 6B&S twin sheathed which I'll common together to make one fat cable for each + & - run. That should give me battery cable size throughout.

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## Cuppa

> This is the VSR I was thinking of getting. The only difference between it and others that I can see is it seems to leave the batteries coupled until 12 v is seen at the cranker rather than 12.8. His reasoning is that it's better to be drawing from 2 or 3 batteries limiting overall discharge which then supports his claim (according to him) that the alternator will recharge way faster than any dcdc could ever hope to for a given amount of drive time. He also claims that it's only calcium/calcium batteries that require over 14.5 to reach 100% SOC (which is true) so any battery will charge to pretty much 100% with 13.2+ . He is fiesty and defends his product ( he makes it) on various forums with gusto. You can click on "isolators" to see his full range. The other feature of his gear is the output can be split or coupled.  SC80 - 90 amps Standard Isolator | TRAXIDE - RV | Traxide - RV

  Ah yes, Tim, aka 'Drivesafe'. He may well have a reasonable product, but his defence generally presents in the form of rubbishing any alternative, which I must admit has an opposite to desired effect on me.  
The idea of having a lower cut out threshold voltage making a bit more of the crank battery capacity available for aux use is reasonable, but I'm less certain about some of his other assumptions & assertions. He's been banging on about them for years & one has to wonder why, if he has a product which is superior to anything else on the market, why it is that other manufacturers have not followed his lead. I could well be wrong, but I suspect that most of his arguments are about merely supporting 'differentiation' of his product.    
If you are happy with the lower cut off threshold no problem, but I suspect that apart from utilising extra capacity from the crank battery (& potentially shortening it's life?) that the faster charging etc is 'spin', but I have no evidence for that suspicion one way or the other.

----------


## Bros

> This is the VSR I was thinking of getting. The only difference between it and others that I can see is it seems to leave the batteries coupled until 12 v is seen at the cranker rather than 12.8. His reasoning is that it's better to be drawing from 2 or 3 batteries limiting overall discharge which then supports his claim (according to him) that the alternator will recharge way faster than any dcdc could ever hope to for a given amount of drive time. He also claims that it's only calcium/calcium batteries that require over 14.5 to reach 100% SOC (which is true) so any battery will charge to pretty much 100% with 13.2+ . He is fiesty and defends his product ( he makes it) on various forums with gusto. You can click on "isolators" to see his full range. The other feature of his gear is the output can be split or coupled.  SC80 - 90 amps Standard Isolator | TRAXIDE - RV | Traxide - RV

  Notice that are ll claims there are no posted figures to substantiate them. When I looked at his Roll Royce system SC80-12 I was turned off a the uses a cheap auto re settable circuit breaker. These things have two uses one for caravan brakes where the power is supplied for a short time and it will be in fault mode for short time and the rubbish bin. 
He's saturated the forums about pushing his product but as I said before there are no facts to support his claim.

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## ringtail

Yep, totally agree Bros. it would be good to have or build a variable cut out for the cranker though. 12.8 is too high IMO

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## ringtail

> Ah yes, Tim, aka 'Drivesafe'. He may well have a reasonable product, but his defence generally presents in the form of rubbishing any alternative, which I must admit has an opposite to desired effect on me.  
> The idea of having a lower cut out threshold voltage making a bit more of the crank battery capacity available for aux use is reasonable, but I'm less certain about some of his other assumptions & assertions. He's been banging on about them for years & one has to wonder why, if he has a product which is superior to anything else on the market, why it is that other manufacturers have not followed his lead. I could well be wrong, but I suspect that most of his arguments are about merely supporting 'differentiation' of his product.    
> If you are happy with the lower cut off threshold no problem, but I suspect that apart from utilising extra capacity from the crank battery (& potentially shortening it's life?) that the faster charging etc is 'spin', but I have no evidence for that suspicion one way or the other.

  yep, a lot of smoke and mirrors with him on the forums

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## chrisp

> Yep, totally agree Bros. it would be good to have or build a variable cut out for the cranker though. 12.8 is too high IMO

  That's sort of what I was thinking too. He may have missed a potential market.  He could have made a product with settable or configable cut-offs and let the user decide what setting are best for themselves.

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## Cuppa

> Yep, totally agree Bros. it would be good to have or build a variable cut out for the cranker though. 12.8 is too high IMO

  I'm sure there is at least one VSR on the market with user settable thresholds, but for the life of me I can't recall the brand. I seem to remember coming across it & thinking it was a good idea. The barely functioning memory cells suggest to me that it had a blue case.

----------


## Bros

> That's sort of what I was thinking too. He may have missed a potential market.  He could have made a product with settable or configable cut-offs and let the user decide what setting are best for themselves.

  Some may like variable cut out some not. It would be OK with the battery new but when it get a bit of age on it I would feel better with a higher voltage.
It would have been easy to set up test rig and run number of tests comparing his VSR with others on the market and publish his data but this is missing.

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## Cuppa

This is the user adjustable VSR I was thinking of.        Programmable Voltage Sensing Relay 12VDC | Amelec Australia

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## ringtail

Cool. I'll make some enquiries. 
had my own little battery moment today. I had a N70ZZ calcium on the charger in the workshop. It had been on for a few hours just as a top up as it's a spare and just sits on the ground on a piece of ply. Anyway, turned the charger off. Picked up the grinder to cut some metal. Some sparks from the grinder went near the battery and ka boom. 1 exploded battery. Never seen it before. Work shop is well ventilated and a really stiff breeze blowing right through today. 
Hosed out the workshop and hosed down the walls. Hosed everything that had acid on it. The 2 end cells were pretty empty but the middle 4 were still full. What to do next. Tip the acid out into a plastic oil drain tray. Then pour the acid into a old oil container. Sweet. Just need to dispose of the acid. Now the silly bit. Told my neighbour about it and he said just neutralise it with some bicarb or lime. Easy. Ok, lets pour a little it into a plastic bucket and neutralise it. I reckon no more than 300 ml of acid and bi carb added a touch at a time. It wont neutralise. Just keeps exotherming. Add water to cool it down. Now I have 1 sealed container with just acid and I poured the exotherming acid/water mix ( about 5 lt) into another sealed container ( lid is OFF) and I'm wondering what to do. Keep adding bi carb and hope it neutralises ? I can't put the lid on the container until it finishes neutralising if it ever finishes

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## chrisp

> Cool. I'll make some enquiries. 
> had my own little battery moment today. I had a N70ZZ calcium on the charger in the workshop. It had been on for a few hours just as a top up as it's a spare and just sits on the ground on a piece of ply. Anyway, turned the charger off. Picked up the grinder to cut some metal. Some sparks from the grinder went near the battery and ka boom. 1 exploded battery. Never seen it before. Work shop is well ventilated and a really stiff breeze blowing right through today. 
> Hosed out the workshop and hosed down the walls. Hosed everything that had acid on it. The 2 end cells were pretty empty but the middle 4 were still full. What to do next. Tip the acid out into a plastic oil drain tray. Then pour the acid into a old oil container. Sweet. Just need to dispose of the acid. Now the silly bit. Told my neighbour about it and he said just neutralise it with some bicarb or lime. Easy. Ok, lets pour a little it into a plastic bucket and neutralise it. I reckon no more than 300 ml of acid and bi carb added a touch at a time. It wont neutralise. Just keeps exotherming. Add water to cool it down. Now I have 1 sealed container with just acid and I poured the exotherming acid/water mix ( about 5 lt) into another sealed container ( lid is OFF) and I'm wondering what to do. Keep adding bi carb and hope it neutralises ? I can't put the lid on the container until it finishes neutralising if it ever finishes

  Don't put a tight fitting lid on it if you have used baking soda - is it will produce carbon dioxide and pressure.  You don't need a jar of acid exploding too!  Just keep slowly neutralising it. 
Anyway, the incident is a reminder of the dangers of lead acid batteries.  If a cell voltage goes over about 2.45V that cell will gass as the water will disassociate into hydrogen and oxygen in the perfect ratio to be explosive.  I'd guess that your battery may have a faulty cell or it was out of balance (unequalised) and a cell or two gassed.  Even sealed lead acid batteries have vents to release any excessive pressure and can release gas.  *I strongly suggest never disconnecting a battery charger at the battery while the charger in on - as there is a remote chance of a spark and if the battery has gassed - it could explode in one's face.*

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## chrisp

Oh, and it is (add) acid-to-water, not water-to-acid if you want to dilute it.  And use a face shield too.

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## ringtail

Not sure what the go was with the battery. It's not that old and came out of my pajero. Sealed MF calcium/calcium. At least it exploded exactly how they are meant to. Even though I was facing away from it, the explosion seemed somewhat controlled and I got no acid on me at all despite being only 2 mt away. The neutralising mix is now in a 20 lt plastic oil contaner - heavy construction like a fuel tank. My biggest concern is the heat from the exotherm. I could sit the container in a bigger container of water to keep it cooler.

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## chrisp

Let it cool before adding anything else to it.  The water bath idea to cool is probably a good idea if it is safe to move it.  Maybe search for a sulphuric acid msds and read up before doing too much more.

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## ringtail

Read up on it and controlling the exotherm temps is the biggest issue, particularly in the high % stuff. If it spills on the ground it's not a problem, just pile on the bi carb. In a container or recycling unit they just add water to control the temp. I don't want to end up with a 20 lt container of neutralised acid of which 300ml is acid. That's nuts. I have seen some reference to 1 pound of bicarb per 1 pint of acid.

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## Cuppa

> Anyway, the incident is a reminder of the dangers of lead acid batteries.  If a cell voltage goes over about 2.45V that cell will gass as the water will disassociate into hydrogen and oxygen in the perfect ratio to be explosive.  I'd guess that your battery may have a faulty cell or it was out of balance (unequalised) and a cell or two gassed.  Even sealed lead acid batteries have vents to release any excessive pressure and can release gas.  *I strongly suggest never disconnecting a battery charger at the battery while the charger in on - as there is a remote chance of a spark and if the battery has gassed - it could explode in one's face.*

  Good advice. I too had a battery explode once. Only a small starter battery on a quad bike. Breather tube had become blocked, pressure built up. Turned the ignition key & Kerbang!  Split the battery wide open. Very lucky not to get sprayed with acid. Scary stuff indeed. My assumption is that in conjunction with the buid up of internal pressure it must have had an internal short to spark the explosion.  
Just on the gassing - wet batteries will always gas if being properly charged on a smart charger/solar regulator. Fom Ringtail's experience in a well ventilated area it brings home the danger that some folk unwittingly put themselves in by mounting wet batteries inside the confines of a vehicle/camper, increasing the risk of explosion. And then to make things worse place a regulator, inverter, fan or other potential source of a spark close by. 
Glad your experience left you unscathed  Ringtail.

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## Bros

> had my own little battery moment today. I had a N70ZZ calcium on the charger in the workshop. It had been on for a few hours just as a top up as it's a spare and just sits on the ground on a piece of ply. Anyway, turned the charger off. Picked up the grinder to cut some metal. Some sparks from the grinder went near the battery and ka boom. 1 exploded battery. Never seen it before. Work shop is well ventilated and a really stiff breeze blowing right through today.

  You were extremely unlucky as the spark must have enough energy to ignite the mixture and it would have been right on top of the battery as the hydrogen will quickly combine with the air and become non explosive.

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## Window575

wow, thought I was only away for a day or two...
I could only get hold of 20a dc breakers from jaycar at short notice last week, so I put them in. Ran the system for 4 days and it worked nicely, given it had a load the whole time though. A knowledgable neighbour had a quick look at the setup and thought it was either overcharging or bad wiring as suggested here. Happy to get the breakers suggested here also. 
A couple of things before I get roasted. Inverter is even bigger than I said. Ideally I would have more isolating switches. Missing some cable ties, but you get the idea.
Photo is with the new breakers installed- crimp connectors but was thorough putting them together. I have left the system on with a load from the inverter while away. Solar cable to the mppt and into the batteries is 4mm2 DC solar cable, not the thin stuff.
I'm was getting 17v roughly from the panels, 13.8v max to the batteries, I have set the mppt to sealed led acid.

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## Window575

What is the best way to dispose of the swollen batteries? The damaged one have been out of the system for a few weeks now but still pretty big in size.

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## Bros

I'll roast you then. You have not set the load supplies up from the batteries the recommended way it should be the same as the solar supply. If you go any bigger is solar which you should you need to double up the solar controller to the battery cables.

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## Cuppa

The inverter has the capability of pulling 460+ Amps from the batteries for a surge load & over 230 Amps continuous so needs a heavier cable, in fact i think it would need to be significantly thicker than your solar supply cables.  
Recyclers will often take dead batteries.

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## Window575

> I'll roast you then. You have not set the load supplies up from the batteries the recommended way it should be the same as the solar supply. If you go any bigger is solar which you should you need to double up the solar controller to the battery cables.

  Ok, will fix that too, sorry thought was only from controller to batteries.

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## Window575

> The inverter has the capability of pulling 460+ Amps from the batteries for a surge load & over 230 Amps continuous so needs a heavier cable, in fact i think it would need to be significantly thicker than your solar supply cables.  
> Recyclers will often take dead batteries.

   Battery cable is 10mm diameter, cable only measurement without shield. (2/0 awg?)

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## Bros

> Ok, will fix that too, sorry thought was only from controller to batteries.

  If you do add more solar don't just parallel with the others at the panels bring the cables to the controller and parallel it there. As for the old batteries the scrappies may give you a few shillings. 
 Last I heard the batteries are shipped to China who do the dirty work.

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## ringtail

My battery acid fully neutralised. It took about 1.5 kg of bicarb. Now I'm left with a 4lt container with about 2 lt of acid/water mix at full strength and a 20 lt container with about 8 lt neutralised acid/water. Both shall go to the dump on their special hazardous waste days.  
Agree with a cable size increase for the OP too. 
So back to batteries. The exploder was the cranker out of my pajero. I ran a circuit breaker and (little 6 mm) wires to the rear of the paj to a second battery. Crude as. I suspect the cranker was being overcharged and was damaged hence the kaboom. Which leads me to the question. With a VSR, what stops the cranker being overcharged if one is running say, a lead acid cranker and an AGM aux ? I regularly saw over 15 v on the paj's volt meter but it is really primitive. Multi meter said high very 14's which I thought was fine as both cranker and aux were calcium/calcium.

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## chrisp

> So back to batteries. The exploder was the cranker out of my pajero. I ran a circuit breaker and (little 6 mm) wires to the rear of the paj to a second battery. Crude as. I suspect the cranker was being overcharged and was damaged hence the kaboom. Which leads me to the question. With a VSR, what stops the cranker being overcharged if one is running say, a lead acid cranker and an AGM aux ? I regularly saw over 15 v on the paj's volt meter but it is really primitive. Multi meter said high very 14's which I thought was fine as both cranker and aux were calcium/calcium.

  Your question is a little confusing. AGM is a type of seperate used in a battery, and you mention cranker (SLI) and auxiliary (deep cycle?). 
The main problem would be if the vehicle battery (often referred to a SLI application) is a flooded battery whereas the auxiliary may have been a sealed-lead-acid (SLA commonly a VRLA). 
Flooded batteries can tolerate a higher charging voltage as they are usually intended to gas (and therefore require topping up with water).  SLA/VRLA (maintenance-free) are designed to contain the water and not vent - and therefore require a more strict control and limiting of the charging voltage. 
You can get away with charging a flooded battery using a VRLA charger but you shouldn't use a flooded battery charger on a VRLA!

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## Bros

I'll check it out tomorrow as I will set my Scanguage on Volts and see the reading. 
All vehicles with very few exceptions parallel AGM aux batteries with flooded cranking.

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## ringtail

A calcium battery is still a flooded battery but has calcium paste on the plates. They require the highest voltage of all batteries to attain full charge, typically 14.5-14.9 V. As Bros said in nearly all cases there are different batteries used for crank and aux. Whether the difference is the type of construction (flooded, gel, agm etc...) or the application (crank, deep cycle, semi cycle etc...) there is nearly always a difference. This is why dcdc chargers have exploded in popularity. The myth or otherwise that surrounds charging two different types of batteries has increased their sales enormously.  
Another possible alternative for charging aux batteries is to hard wire an inverter to the cranker and run a 240v smart charger from the inverter purely to charge the aux battery/s. Going from dc to ac then back to dc always seems a bit counter productive to me but I think the concept has merit. 
Maybe ( and I can't believe I'm saying it) this thread needs splitting into "Aux battery set up"  :Biggrin:

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## phild01

> Another possible alternative for charging aux batteries is to hard wire an inverter to the cranker and run a 240v smart charger from the inverter purely to charge the aux battery/s. Going from dc to ac then back to dc always seems a bit counter productive to me but I think the concept has merit.

   I had that set-up already. On a trip the charger karked it and replaced the lot with a ctek.

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## chrisp

> A calcium battery is still a flooded battery but has calcium paste on the plates. They require the highest voltage of all batteries to attain full charge, typically 14.5-14.9 V. As Bros said in nearly all cases there are different batteries used for crank and aux. Whether the difference is the type of construction (flooded, gel, agm etc...) or the application (crank, deep cycle, semi cycle etc...) there is nearly always a difference. This is why dcdc chargers have exploded in popularity. The myth or otherwise that surrounds charging two different types of batteries has increased their sales enormously.  
> Another possible alternative for charging aux batteries is to hard wire an inverter to the cranker and run a 240v smart charger from the inverter purely to charge the aux battery/s. Going from dc to ac then back to dc always seems a bit counter productive to me but I think the concept has merit. 
> Maybe ( and I can't believe I'm saying it) this thread needs splitting into "Aux battery set up"

  There are definitely differences in the chargers for sealed and flooded batteries.  Sealed batteries do need to be charged with an appropriate charger or there is a risk of gassing and the possibility of an explosion. 
Just because sealed and flooded are seemingly commonly connected in parallel as an auxiliary battery, it might not actually be the case. Many modern cars used sealed batteries and the charging system will suit a sealed auxiliary battery.  Some cars have quite low voltage regulators in their alternator (mainly due to the temperature sensor for the voltage compensation being in the hot alternator instead of on the battery!). 
The calcium in the battery makes no practical difference to the (top-of-charge) charging voltage with respect to gassing.  Check with the manufacturer if you have doubts - http://www.centurybatteries.com.au/c...y-charging.pdf  The calcium does make the battery more prone to acid stratification if they are deeply discharged so they can benefit from some gassing to remix the acid from time to time, but this needs to be done in a controlled manner and limited in duration as gassing is still gassing - with all the risks associated with charging a sealed battery to gassing potential. 
The better way to charge the auxiliary battery in a vehicle (especially if it is a sealed type) would be to use a charger designed to be powered from a vehicle 12V system - such as Ridge Ryder 12v Battery Charger - DC-DC In Vehicle, 20 Amp - Supercheap Auto 
I am somewhat perplexed by your cavalier attitude ("myth or otherwise that surrounds charging two different types of batteries") considering that you recently experienced what happens when a sealed battery gasses and explodes.  Anyway, you can decide for yourself how you want to mix and connect your batteries and what risks you are prepared to (unwittingly) take, but I will try and correct the misinformation when I see it.  :Smilie:

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## ringtail

WTF ? Cavalier attitude ? Where did that come from ? I suggest you read post 105 then read 106 again. Cavalier attitude, pfffft.

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## Bros

> I'll check it out tomorrow as I will set my Scanguage on Volts and see the reading. 
> All vehicles with very few exceptions parallel AGM aux batteries with flooded cranking.

  As promised 14.1 for the half hour duration.

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## Smurf

> What is the best way to dispose of the swollen batteries?

  Scrap metal place may give you a few $ for them or at least take them off your hands at no cost to you. 
Battery shops will often take them at no cost (they then sell them for scrap metal). 
Not sure if this is the case in all areas but around here you can simply drop old batteries off for recycling at the tip. Council keeps the $ from the scrap metal, they don't pay you for it, but I'm fine with that since it's a free (to me) service as such to just drop things off for recycling and it's obviously better than having them end up in landfill.

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## ringtail

> As promised 14.1 for the half hour duration.

  Yep, no surprises there.

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## Window575

I think highjacked is a word I can safely use at this point. But thanks y'all for your help.

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## ringtail

Just killing time until you post  :Biggrin:

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## Window575

Getting onto upgrades of this shortly. Have just got 2x 32a two pole dc breakers (non polarised- Noark).
I plan on putting one between the the panels and charge controller, and one between the charge controller and the battery bank. The only labelling on the breaker is 1,3 (at the top), 2,4 (at the bottom).
Could I get verification on the correct way to wire for both installs? 
Thanks.

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## Window575

Asking again guys, can you help me out?
It may be a very basic questions I'm asking, but I can't find any info on the wiring symbols that are on the breakers I have. 
I assume "in at the top and out at the bottom" but I'm done with assumptions. Especially with 2 pole stuff.
Is this the way to go?
+(in) on pole 1, and - (in) on pole 3. 
+ (out) on pole 2, and - (out) on pole 4. 
You have all gone quiet on my time of need! 
thanks :Smilie:

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## chrisp

> Asking again guys, can you help me out?
> It may be a very basic questions I'm asking, but I can't find any info on the wiring symbols that are on the breakers I have. 
> I assume "in at the top and out at the bottom" but I'm done with assumptions. Especially with 2 pole stuff.
> Is this the way to go?
> +(in) on pole 1, and - (in) on pole 3. 
> + (out) on pole 2, and - (out) on pole 4. 
> You have all gone quiet on my time of need! 
> thanks

  you've got it.  The answer was actually in your photo - the diagram on the right hand breaker. 
Usually the 'in' is on the bottom and the 'out' is on the top but it doesn't matter.

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## Window575

Thanks Crisp. I did see the diagram but had no idea on how to read it!

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