R.I.P. or Frankenstein??

Hello all, thanks for a most informative site!!

I recently got my hands on a 48v PBX battery bank that had been sitting idle for at least four (4) years.
They are Exide Dynacel TYPE DD 35-15.

See picture below.
Attachment not found.

I can't seem to find any meaningful documentation on them anywhere, but would like to use them for my RE system if possible.

I presently have eight [8] relatively new Eveready GC2 220AH batteries setup for 24v feeding a Xantrex Prosine 3.0.

I'd planned to purchase four [4] more GC2s, but came across the Exides.

Moving on: If split into sets of three [3] the voltage is only 12v.
I've tried hooking them up to 350W of PV with a C60 CC, but the voltage only rises (rather rapidly) to about 28.8v with only about 1 amp of draw.
They've only been on charge for about three [3] hours so far.
If the CC is switched off, the voltage falls to about 13.6

So... the $64k question is: Are they dead? Or, can they be resurrected??


  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
    Re: R.I.P. or Frankenstein??

    If they have been sitting idle and not connected to some sort of battery charger--they are probably "dead".

    If they were connected to a battery charger (appropriate capacity/rating), then they should be OK.

    You best bet is probably to try charging then discharging with a known load (say a bunch of lights). And see if you can draw 50% to 80% of their capacity before the cells loose voltage.

    Might find that you have a few "bad cells" and the rest could be recovered to make a smaller battery bank.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: R.I.P. or Frankenstein??

    there might be some useful info here, not the same cell but close. search for dynacel. interesting per cell V...


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  • James
    James Solar Expert Posts: 250 ✭✭
    Re: R.I.P. or Frankenstein??

    I agree with BB, A load test will tell you alot. These cells probably can't be equalized, they will most likely pop the vents if you try to hit'em with a higher charge voltage. If they don't look good after the load test, remember if you got them for free, look at them as an offset to the cost of new batteries. You can get around $.20+ a pound for them at the recycle yard