[RE-wrenches] Sick pack

[frenergy]

Gentlemen and women,

        I have been called in to deal with a pack of 16 (4 strings of 4 for 24V), L-16s, 6 years old.  She is having to run her generator 2 times a day.  Here in N.E. CA. its been cold, mostly clear, little wind.  Her inputs are about 1 KW of PV, and small wind machine and of course a serious generator.  Cables and terminals looked clean, were tight.  The bulk setting on the Trace 4024 was 28.0 V for 2 hrs with RTS, however, she would manually turn off the generator soon after it reached 28V.  Recipe for suphation.

        Rather than getting into too much detail, here's my quandary.  When I fired up the generator, the input amps in each of the 4 strings were.... string #1:29A, 2:34 A, 3:25 A, 4: 13 A.  A survey of IR temps throughout the pack gave temps ranging from 63 to 92 degrees.  The highest temps were in the string pulling highest amps.  In trying to find shorted/failed and/or sulphated cells which data are most relevant?  Temps, amp draw during charge, disconnect strings from each other and check volts of each 6 volt batt?, active bubbling? ...all the above?  

        I'm thinking I should have (1) checked the amp draw with batts under load/genny off in each string AND (2) check amps between strings with the pack at rest, no input or output.  I would love to EQ the pack but with a temp already in the 90's and uneven currents in the strings I don't want to risk too high of temp or worse, a runaway situation and fire. I'm thinking I'd like to yank a few bad batts and run on 3 strings and then carefully EQ. 

I appreciate any insights.

Thanks in advance,

Bill
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