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[Home Shop Chemistry] Resurrecting a toasted forklift battery-pack.

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  • [Home Shop Chemistry] Resurrecting a toasted forklift battery-pack.

    So, basically they forgot to put water in it and kept charging it and charging it, and now it won't hold a charge. I put water in it, let it sit, let it charge, let it equalize... nothing.

    It's deceased, destroyed, dysfunctional, voided it's maker's warranty, kaput, finished, bleeding demised. I HAVE NOT tried running 4,000 volts through it because that would cause it to go VOOM and not in the good way.

    So, anyone here have a secret or not-so-secret way to bring the battery back from death? Or is this one of those things that not even the Home Shop Machinist forum can fix.

  • #2
    Short version is once its sulfated you recycle it and buy new, especially if anyone is paying labor hours. Nursing worn out batteries is a good way to spend hundreds of labor $ to save dollars of capital expense when you run the numbers over the lifetime of the machine. If doing it at home for an RV or boat or something its a frustrating hobby.

    Sometimes you can fix very minor sulfation with extended trickle charging but usually its a waste of time, because the reason it was boiled/sulfated is because the plates wore out leaving no/zero capacity so they just kept on charging it longer and longer until it boiled out / sulfated over at which point you've now got two problems so just fixing one of them isn't going to help.

    The plates either wore out because they were used (good, hope it earned you some money) or sat around and after X number of years lead acid cells inherently self destruct. Once acid is added and they're wet you've got maybe 7 years before they corrode out even if they're never taken off the trickle charger (think alarm system battery backup or computer UPS). Either way once the plates are done, they're done. It's like asking how to un-rust a 70s detroit car after its already turned into rust.

    Look up what a patent medicine is, and how they're sold, and then don't buy a marvelous mystery gadget that expensively claims to cure all your batteries ills.


    • #3
      It's only hope is a aggressive equalization cycle. 15.8 volts for 20 hours or so. Not likely to work but may make them usable. Do it several times over a few weeks, checking for water each time. Get a battery acid tester and see where the specific gravity is after an E-cycle. If it shows a bad cell the game is over. Use only distilled or rain water to fill.

      The good news is it is worth $.33 a lb.


      • #4
        See that's what I'm talkin about. Lets say a bank is $1K and you spend ten hours screwing around to make it live 5% longer than if you just scrapped it and bought new. That means you just saved the company a whopping $50 via 10 hours of labor or $5/hr when the company could have billed your time out to a customer at shop rate, which is a bit more than $5/hr. A battery bank is not that cheap, but then again you can spend a lot more than 10 hours nursing the batteries and the machine they're installed in with no guarantee you'll get an extra 5% of life anyway.

        Also, dead batteries really annoy people, or they really annoyed me when I had to nurse them and the machines they were in, a long time ago. If the execs can afford $5000 chairs, they can afford a forklift that won't die in the middle of the warehouse with my part on it and blocking the main aisle. There's a cost to that, too.


        • #5
          I think battery pulsers and ringers are mostly voodoo and wishful thinking.



          • #6
            It is claimed that EDTA (ethylenediaminetetracetic acid in form of sodium salt) can be used to desulfate batteries.
            It is available by mail order with instructions of use and cheap.


            • #7
              A dead forklift battery?

              In barely working condition those things can be hundreds, in new condition, a few thou. Used dealers told us that the forklift is FREE, they charge for the battery. (Boss wants to replace propane lift with electric).

              Scrap it, and throw in the rest of the forklift..... it will be cheaper than a new battery.

              Keep eye on ball.
              Hashim Khan