[RE-wrenches] battery question

[James Surrette]

Morning Jay, 

I don't have a lot of good news for you - but maybe others do?  Years ago, I visited a commercial fishing client that had a 6 week old 32VDC bank of batteries that were "not performing".  Once we reviewed, we noticed a tap 6 cells in.....for 12V radios.  Boat had been out for a 6 week run, which meant 6 weeks of charging at ~2.3VPC and the 10 non tapped cells were toasted (red cases were actually black).  Of course, client wanted warranty but that is another story. 

Your only hope is to separate the "low" 12V bank and charge to 100% SOC.  Then charge the "hi" 12V bank to 100% (probably already there or beyond).  Finally, marry the banks again and "balance" with a 2.35 - 2.4VPC until cell voltage stabilizes.  Current acceptance will be low but voltage will ultimately stabilize across the bank. 

The problem is, the "low" bank has been undercharged for 2 years and the "hi" bank has been severely overcharged.  As a result the capacity / corrosion differences between the two "sides" will be great - leading to charging difficulties going forward, which may result in the bank needing to be replaced.  However, I would recommend attempting to bring the bank into line before replacing. 

I hope this is of assistance, 

Jamie 




James Surrette

Surrette Battery Co. Ltd
1 Station Rd.
Springhill, NS, CAN
B0M 1X0

Direct: 902.597.4027
Fax: 902.597.8447



>>> jay peltz <jay at asis.com> 09/04/08 1:25 AM >>>
HI All,

A guy has 1/2 loaded his big surrette 24v battery,  yep put 12v loads 
onto only one side of the 24v battery.

Now after 2 yrs 12v side is low voltage, 24v side is boiling like crazy.


System is charged via SW4024, big genny and good size array.

so my question is can/should I

1. remove the 12v by installing a Vanner or similar.

2. put a 12v charger onto the lower 12v side to put an equal charge 
into the batteries.
( I have never had success trying to charge up a highly unbalanced 
battery)


thanks,

jay

peltz power
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