Recharging Johnson Control Batteries

I am going to install solar in my Sierra Nevada home. The house is off the grid and currently I use a generator for power. Many years ago a contractor friend of mine gave me six Johnson Control Multi Cell Batteries.They were stored inside. On them is written "580 Amp hr - 8hrs Multi Cell" . I believe they have lead/calcium plates. I do not know if they are 6 volts or 8 volts. The batteries are 12 inches tall and 18 inches long. I have had trouble charging them. I have only been able to get them to hold about 3 volts. If anyone has any suggestions or instruction in how to get them charged, it would be greatly appreciated.



  • BB.BB. Super Moderators, Administrators Posts: 32,997 admin
    Re: Recharging Johnson Control Batteries

    I could not find anything about them... In theory, assuming lead acid chemistry, it should be 2 volts per "cell"... Note that some batteries have two sets of bus bars or other confusing hardware that may lead to wrong guesses on cell count...

    If this is a "6 volt" or higher battery--It is probably dead and not worth playing with. Batteries that have sat below ~75% state of charge for months or years are "sulfated" and most likely are not going to recover very much of their original capacity.

    I don't think you will have any luck with them--but if you want to try charging them, you need to find out what they are (flooded cell, VLRA--valve regulated lead acid, AGM, or Gel Batteries)...

    Other than flooded cell, most of the rest of these batteries respond very poorly to "equalization" (controlled over charging).

    There are a few lead acid storage batteries that have Cadmium as an additive for better performance--Those batteries may require you to pay to get rid of them.

    And Cariboocoot here (typed yesterday) that Gel Cells also are not well accepted by battery recyclers (perhaps the gel electrolyte is difficult to deal with?)--At least his area in BC Canada.
    I hope you didn't pay anything for them.:blush:

    You do not equalize gel batteries or AGMs. You can charge them gently, let them sit for 24 hours, and see how the Voltage holds. But there's nothing else you can do with a gel cell. No way to check SG, desulphators are useless against gelled electrolyte, and you can't add any battery restoratives :roll: either.

    You probably will have difficulty disposing of them too, as scrap yards don't want anything by FLA's it seems.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Recharging Johnson Control Batteries

    how many fill holes are there? each hole is for a cell and each cell is roughly 2v. as bb said 3v is low for a 6v battery, but could you be trying to royally overcharge a 2v cell? in any case it doesn't sound good.
  • System2System2 Posts: 6,290 admin
    Re: Recharging Johnson Control Batteries

    There are four fill holes, so that probably means it is an 8 volt battery. In any case they have sat for a very long time and I am unsure what kind of cells they are. If I can get a hold of the manufactures, then maybe I will be able to do something with them. Thanks for the info.

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Recharging Johnson Control Batteries

    if they are 8v batteries then you need to dispose of them as they are no good.
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