Electrical Battery drained - Help please

[TRAKADU]

I have recently (about 10 months ago) installed a Fullriver 120ah battery as my main one and moved the Jayco generic battery as the second one. These are generally charged by 2 x Solar panels on the roof which generates plenty of juice to charge the dual battery system. However, recently I washed the Panda and put the cover to keep it away from the elements. This morning I opened the door to find out the main battery is totally flat (I mean it shows 5.5V) and the Solar Regulator display unit inside the van constantly beeping. The 12V system has also been cut off so there is no 12v power in the Van. I quickly plugged in the 240 system to charge the batteries hoping it is not too late. Did I stuff up my Battery??? or will it come to life??

By the way, my second battery displays 12.5V. (I thought if they are connected on parallel basis, it should complement each other). I have couple of small units connected the likes of CO/ GAS monitor which only draws a small current.

 

[boots33]

If your batteries are hooked directly in parallel then both batteries should be discharging together. It is not possible for them to discharge at different rates. When you checked your battery voltages were they still connected together ?

The fact that the setec has disconnected the 12v supply indicates it is only seeing the main battery (the flat one) and not your original , you should check the connections between them and maybe look for an in line fuse or some other form of isolation .

The setec will have disconnected the battery when it dropped below 10.5v so if it is now at 5.5v it would indicate the drain has continued. It is either a faulty battery, faulty setec or most likely you have something that is connected directly to the battery that is drawing enough to bring the battery down. Also as i said earlier both batteries should have drained together so you have a wiring problem as well.

How long was the van sitting for before you discovered it was flat.

 

[TRAKADU]

If your batteries are hooked directly in parallel then both batteries should be discharging together. It is not possible for them to discharge at different rates. When you checked your battery voltages were they still connected together ?

The fact that the setec has disconnected the 12v supply indicates it is only seeing the main battery (the flat one) and not your original , you should check the connections between them and maybe look for an in line fuse or some other form of isolation .

The setec will have disconnected the battery when it dropped below 10.5v so if it is now at 5.5v it would indicate the drain has continued. It is either a faulty battery, faulty setec or most likely you have something that is connected directly to the battery that is drawing enough to bring the battery down. Also as i said earlier both batteries should have drained together so you have a wiring problem as well.

How long was the van sitting for before you discovered it was flat.

Hi booty, thanks for the reply.

Yes they were connected together when I checked the voltage. That's what puzzled me too. I do think the same that the setec only detecting the first battery not the second...

Jayco did the wiring for the spare battery. I can only hope they connected it correctly.

Does it have an inline fuse?? If so where is it located??
Can't understand what could draw that much juice out in a shorter time!!!

The van was covered for a about four weeks. So it hasn't been that long. I had it covered before for longer and this never happened!!

 

[yabbietol]

My suggestion is to take off the +ve on each battery and measure the voltage at each battery individually directly at its terminals with no load. You will need a multi meter, for this a cheapo from somewhere like Supercheap will do. They are always a handy thing to own. With some luck one will be very low (>10V) and the other flat. Best guess, it would be the older battery that has died. My guess is a cell has collapsed in one of the two batteries and the other will be trying to compensate. So isolating each battery should tell which is the dud. With some luck only one will be a dud, but it could be both. Winter is the time when batteries die they do not like cold weather.
Generally, it is a good idea if you use batteries in parallel they should be of similar size and age otherwise the weaker battery will always be trying to discharge the better battery.

Good luck

 

[boots33]

Yes they were connected together when I checked the voltage. That's what puzzled me too. I do think the same that the setec only detecting the first battery not the second...

If they were connected together then they should be reading the same voltage, so there must be an open circuit somewhere in the wiring. You will need to follow the wiring from one battery to the other checking all connectors etc for the fault. You will need to check both the negative and positive wiring. close inspection of any crimp terminals for a badly made crimp.

Jayco did the wiring for the spare battery. I can only hope they connected it correctly.

It is a bit hard to make an informed opinion without being able to look at the wiring first hand but from what you have said I would think you have got some sort of problem with the setup.

Does it have an inline fuse?? If so where is it located??

There is no real "standard setup" that jayco use when it comes to wiring. As for a fuse, if the batteries are mounted side by side then usually no fuse will be fitted. If the batteries are mounted some distance apart and the connecting wiring is running through bulkheads etc. then a fuse should be fitted at both ends of the connecting wire. It is usually placed as close as is practical to the battery.

Can't understand what could draw that much juice out in a shorter time!!!

all lead acid batteries will self discharge over time, add to this the standby draw of other electrical items that may be connected and you will be surprised just how quickly they will drain. You will need to do a current draw test to see how much standby power is being drawn.

The van was covered for a about four weeks. So it hasn't been that long. I had it covered before for longer and this never happened!!

Have you added anything electrical to your van since you last stored it? If so that may be the culprit.


@TRAKADU it would seem you may have a couple of different faults there and they should be fairly easy for an auto sparky to track down if you are having hard time locating the fault.
The original hookup was done by jayco there may also be some warranty so it might be worth a call to your dealer for assistance. As to the condition of the battery that was discharged down to 5v it will almost certainly have suffered some damage as a result.

 

[yabbietol]

Further to my above, try to had a look at each battery in isolation with no load. This is something you should do as soon as you find a fault with any parallel battery system. If a modern sealed battery has a collapsed cell the they are beyond economic rescue. The dead battery with a dead cell will damage any battery hooked up with it in parallel. So do make sure you separate the batteries, if you suspect one dead battery as soon as practical.

If a battery is left discharged for a period of time you will get a build up on the plates inside the battery and by charging you may remove the coating, but this will only work if the battery has no serious internal problems. A collapsed cell is usually a result of vibration, rapid discharge, sediment or just he the plates in the cell getting old and warping, once they warp they can short out and build up heat and destroy the cell. Note 12V batteries are made up of six cells and it only takes one cell to fail. In the older style large batteries they had rubber cases and bitumen tops and a cell could be replaced by melting the bitumen and replacing the dud cell, these days due to sealed cases this is not possible.

In summary, I suggest before fault finding the wiring, check each battery in isolation, if you have a flat battery little is lost by trying to charge it, but try it one at a time not both in parallel. If you are looking at replacing one parallel battery think seriously about replacing the two, or at a minimum if replacing one, matching the batteries the best you can in capacity and manufacturer.

 

[TRAKADU]

Thanks Boots33.
On the weekend I finally had the time to check out what's going on and I think I have found couple of issues. The inline fuse (to the second battery) was blown and as a result the second battery was not on the circuit which explains the higher volt reading than the other one. I also disconnected the load from the both batteries and checked their voltage individually. The reading was similar to that of the first reading (5.5V and 12.5V). Then I replaced the blown fuse with a new fuse and connected the full circuit. The reading was approx. 10.5V which indicates to me the higher voltage battery (second one) was trying to compensate the lower one. I then isolated the second good battery and tried to charge the first one for 24 hours but unfortunately had no luck. (which tells me it spat the dummy). . The Battery is covered under warranty by the manufacturer which I am heading there today for a replacement (fingers X).

However, it still begs the question on how it drained a quality made battery (Full River) to 5.5V even after Setec cut off the circuit at 10.5V.!!
It could well be a dud battery. Anyway, I'll keep you posted on the progress...

Thanks for the help guys Trakadu

 

[boots33]

Sounds like your hot on the trail...
Yes please do let us know the final result.

Just as a side note. If you were using the setec to try and charge your battery it probably wouldn't have made much headway. Once the setec low voltage cut out activates it will only trickle charge the battery at less than 1Amp until the battery voltage reaches around 11.5v , then it reconnects and makes the full charge rate available. With your battery being so flat i doubt it would have got high enough to reset the cut out.

 

[yabbietol]

Sounds like you have found the dud battery, good luck with getting a new one.

 

[TRAKADU]

I returned the battery to the supplier. They are going to send it back to the manufacturer for assessment. I should hopefully hear from them in a week. I would rather get a replacement battery as I think the old one could well be damaged by now. Anyway, let's see how we go.