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Gel-Cell Battery repair?

Discussion in 'Electronic Repair' started by Chris F., Aug 14, 2005.

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  1. Chris F.

    Chris F. Guest

    I got a couple of rather large gel-cell batteries the other day (the
    largest is a 12V 24ah) but it turns out they weren't such a great find.
    Neither will take a charge; with the charger connected, neither battery will
    draw so much as a single milliamp. Both batteries have a number of little
    round covers; underneath the covers are small rubber caps covering a hole. I
    noted that when I removed one of the rubber caps, there was a small inrush
    of air as if there was a vacuum inside. My guess is that both batteries have
    "dried up", possibly from lack of use. Is it as simple as adding water, and
    if so, exactly how much and what kind (distilled, tap, etc) should be used?
    Thanks for any advice.
     
  2. That's not large;-) We use 100 Ah types for powering location broadcasting
    units. And that limit is purely through the weight for carrying.
    IMHO, when any type of lead acid is dead, it's dead. If they've been left
    discharged for any length of time for whatever reason they can't be sorted.
     
  3. Jerry G.

    Jerry G. Guest

    Gell cells are not servicable. They must be replaced when they go
    defective. You are supposed to have the old ones properly disposed of.


    Jerry G.
    ======
     
  4. Chris F.

    Chris F. Guest

    So what's with the little covered panels on top? I thought maybe it was a
    place to add water.....
     
  5. 3T39

    3T39 Guest

    Hello, Chris!
    You wrote on Sun, 14 Aug 2005 22:33:19 GMT:


    CF> ??>> Gell cells are not servicable. They must be replaced when they go
    ??>> defective. You are supposed to have the old ones properly disposed of.
    ??>>
    ??>> Jerry G.
    ??>> ======
    CF> So what's with the little covered panels on top? I thought maybe it was
    CF> a place to add water.....

    Nope, they are there to provide a safety vent in case of a fault developing
    that might otherwise cause a bang.


    With best regards, 3T39. E-mail:
     
  6. James Sweet

    James Sweet Guest


    That's easy enough, anywhere that sells car batteries will take just about
    any sort of dead lead acid batteries for disposal. I take them down to the
    local Schucks autoparts.
     
  7. Chris F.

    Chris F. Guest

    Is there any way to "revive" them by applying higher charge voltage or
    something?
     
  8. No.
     
  9. Chris F.

    Chris F. Guest

    I found a website that had plans for a "desulfator" that claims to be able
    to revive at least a small percentage of such dead batteries. These
    batteries probably failed from sulfation, as they were hardly used and kept
    in storage for years. I'll give it a try sometime.
     
  10. Jim Adney

    Jim Adney Guest

    Sulfation can be cured by long slow trickle charging, but cells which
    have actually dried out can only be fixed by adding water. In most gel
    cells and starved lead acid cells this is difficult, if not
    impossible.

    Unfortunately, the onex I had were dried out, and even after cutting
    one of them open, I couldn't figure out any reasonable way to get
    water in there without destroying them.

    -
     
  11. Chris F.

    Chris F. Guest

    This may mean something, maybe not. I lifted off one of the rubber caps, and
    tried poking a small rod down through. There seemed to be a hard film on
    top, but underneath the gel appeared to be at least moderately wet. I'm
    guessing that perhaps poking a hole in the hard film, then adding water,
    might just work.
     
  12. James Sweet

    James Sweet Guest


    Not if they're sulfated. I suppose you've got nothing to lose by trying but
    I've never had any luck getting truly dead lead acid batteries of any type
    to take a charge. Sometimes if you hit them with a higher voltage they'll
    charge a bit, but they never last long.
     
  13. Jim Adney

    Jim Adney Guest

    There's no harm in trying, and it might actually work. The problem is
    that you really don't know how far in the elecrolyte gel is. If you
    can actually get the water to it, you're all set. In the Gates Cyclon
    cells I took apart, there was a similar cap, but going down that hole
    only got me half way to the active part of the cell.

    -
     
  14. Chris F.

    Chris F. Guest

    Here's some interesting plans for a battery desulfator:
    http://www.shaka.com/~kalepa/desulf.htm
    People claim to have good luck with it, so I might give it a try. Cheaper
    than buying new gel-cells, that's for sure.
     
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