# Please help - problem with new battery bank!



## ani's ark (May 12, 2012)

Hi all, looking for experts on batteries and solar controllers. 

We are running our house offgrid on a 1kW inverter from a battery bank of 4 x 12v 200amp hours lead acid batteries, charged by a 400w wind turbine and 8 x 80w BP solar panels. The system is 3 years old, has been great. 

We recently were given a set of 8 x 12v 105amp hour sealed gel lead acid batteries at their half life and are trying to connect them as the main battery bank, keeping the old set as a backup bank with a switch between to alternate charging on sunny days in winter.

The problem is that when connected, the solar controller reads the voltage on the gel batteries as being fully charged (impossible) when connected to the PV cells. This wont allow them to start charging. Then, with even the inverter being turned on, even a tiny load on the batteries, shows a catasrophic drop in the voltage. Down to 5.6v!!! 

Has anyone encountered this issue when using a different kind of battery on an existing controller? The controller is ok to use with this battery type.
DH is trying a voltage sensor cable off the batteries, but has spent many hours fiddling and is at his wits end!


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## 12vman (Feb 17, 2004)

I'd say the gel cells are junk. Do you know how they were cared for before you received them? It's not hard to overcharge them and they will dry up..


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## Fire-Man (Apr 30, 2005)

I agree with 12vman, but I would load test each one and do a double check on all connections if they pass the load test. I have seen alot of them read 12 volts with a volt meter until they go under a Load.


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## Jim-mi (May 15, 2002)

What is the voltage of your system . .??

If it is 12v and you have all these batteries hooked up in parallel you will have nothing but problems.....
One sick bat will mess up the whole bunch.....

Load test each bat with at least 10 amps load, and record the voltage.


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## ani's ark (May 12, 2012)

Thanks for the responses. 
They are from a museum back-up power system, so it's quite possible they are junk. Good plan, we'll put them on a load test each. And put in a different sensor cable from the batteries to the solar controller, too. 

We are not running the flooded and the gel batteries all in parallel as we are aware of the problems that can create. So we have set up two banks. This problem is occuring on just the bank of gel batteries. Flooded still works fine, thank goodness. 

We'll come back if we find out the problem.


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## ani's ark (May 12, 2012)

Well you guys were right, it seems the batteries are shot. Bummer, we were all excited about running 2 battery banks giving us way more power. But it was not to be.

Tested 4 on voltmeter - volts high, no amps. We put 2 of them on a 20 hour trickle charge at a diesel mechanic neighbours battery charger, but they still accept no current. Voltage does read high, but no ampage. 

So the moral of the story is....*do* look a gift horse in the mouth. Arrange to test any halflife batteries volts AND amps, BEFORE you drive 600km round trip(family member had them for us), loading 250kgs of batteries in and out of your car and spending money on cables and switches! Gaah. Oh well, win some lose some.


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## Fire-Man (Apr 30, 2005)

ani's ark said:


> Well you guys were right, it seems the batteries are shot. Bummer, we were all excited about running 2 battery banks giving us way more power. But it was not to be.
> 
> Tested 4 on voltmeter - volts high, no amps. We put 2 of them on a 20 hour trickle charge at a diesel mechanic neighbours battery charger, but they still accept no current. Voltage does read high, but no ampage.
> 
> So the moral of the story is....*do* look a gift horse in the mouth. Arrange to test any halflife batteries volts AND amps, BEFORE you drive 600km round trip(family member had them for us), loading 250kgs of batteries in and out of your car and spending money on cables and switches! Gaah. Oh well, win some lose some.


I Take a battery Load Tester with me EVERY Where I Go.


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