Forklift Batteries

fvrdbauer
fvrdbauer Registered Users Posts: 8 ✭
in General Solar Power Topics #1
I have a couple of 24v (440amp hr)forklift batteries I want to put on my system. I have a xantex xw6048. I have tied them together to get my 48v. However these come from a guy who was going to scrape them so he gave them to me not knowing whether they work or not. One is great I filled it up and charged it. The other one I did the same thing when I hooked them up to my system the XW6048 reads a fault under voltage;so I put my multitester on each cell they all read at or a little above 2.0v except one it varies big time in vloltage Im not sure if that cell does have a short in it? I have some smaller batteries I was just hoping these would work especiallly for FREE. So the one cell the voltage ranges from 1.5v- 5.7
nothing constant, the string of 24v flucuates the same way thats what leads me to believe it my have a short causing the fault light to come on;the other side of the 24v stays a constant voltage. Is there anyway I can fix this to hook them up to my system?? the batteries are 13w x 36l 28h I could only siphon off so much of the fluids which was very little due to a plate in the cell then I put fresh distilled water in it and put a 24v charge on it. I tried to equalize the batteries with the XW system but it would allow me to do it Im assuming it was because of the one cell. when I run it for about five minutes the top plate are very warm. Even though it is like this could they still be hooked up and run on the XW even though it show a a dc under voltage fault i do have a desulfator I could hook to it.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Forklift Batteries

    There has been lots of talk about getting used fork lift batteries and installing them in solar systems...

    And, each battery seems to be different in terms of both quality (present condition) and how the cells are connected.

    In general, if you can find several fork lift batteries of the same brand/model/capacity--then charge/discharge through a few cycles (using fairly heavy current)--while watching which cells seem to behave out of the ordinary (very low or very high voltage--open or shorted cells).

    At least one person here was able to disconnect "bad cells" and use the rest very successfully for his off-grid fabrication business in Hawaii. One advantage he had was using 32 volt batteries instead--That gave him three "extra cells" to play with... He would maybe find one "dead" cell and be able to keep the other two cells disconnected (and charged once in a while) for reserve.

    Just "equalizing" a battery is (apparently) not good enough to recondition (don't "cook your battery" just by equalizing it). Deep cycling/charging appears to do a better job of it. Monitor cell voltage and specific gravity so you can identify bad cells and get them out of the series string (if possible with your battery's construction.

    Only add distilled water (never top off with acid unless the acid has been drained--and even then, you how much acid to add is always a question).

    Here is one recent thread discussing the details of salvaging a forklift battery.

    And just for an education (few people will do this today):
    BB. wrote: »
    Eric/Westbranch posted a link to a 1922 battery repair manual. A very interesting read and look back almost 90 years at technology and mass production (near the end are some factory photographs).

    Antique battery info (1922) (thread)

    And here is the direct link to the table of contents:

    THE AUTOMOBILE STORAGE BATTERY ITS CARE AND REPAIR

    Despite the title, also includes information on storage batteries too (Farm Lighting Batteries).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • fvrdbauer
    fvrdbauer Registered Users Posts: 8 ✭
    #3
    Re: Forklift Batteries

    I read the treads very interesting ,tell me how are they putting a 80amp charge on the battery? What would I have to do with these 24v batteries to get them to bubble like they were talking about. I have a 24v slow charger and a 12v 6amp charger are these any good for anything or do I need something else? I found the weak cell,it must be shorted I would guess; the voltage varies. Could you put the 12v 6 amp charger on the 12v side of the 24v battery the 24v charger is only 2.5 amps. It would be nice to salvage this battery.The other 24v battery is still holding its charge and working fine.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Forklift Batteries

    Yes, you can charge a section of the battery to 100% charge... But you do not usually want to charge a 24 volt battery with multiple 12 and 6 volt chargers as a matter of standard practice (could be done--but you have to be careful).

    Generally, for a minimum charging current that will give you a good/vigorous charge--5% of the 20 Hour Battery Rating is a good minimum (about 13% is a typical maximum for a flooded cell battery).
    • 440 AH * 0.05 rate of charge = 22 amps minimum
    And the charger needs to be able to supply 22+ amps of current at 30-31 volts (15-15.5 volts for a 12 volt charger)... Typical automotive battery chargers are not usually capable of doing such a thing.

    Big forklift chargers are expensive and consume quite a bit of power. Roughly for an 8 hour charger:
    • 440 AH * 0.13 rate of charge * 29 volts charging * 1/0.80 efficiency = 2,074 watts minimum
    You might try a 24 volt 2.2 amp charger for several weeks, once the battery is fully charged to see if you can reverse some of the sulfation damage (debatable how well this will work).

    Regarding desulfators--A very controversial subject. Some folks believe they work well--Others think they are pretty much worthless... Many people that have tried them seem to "recover" a bad battery or two and then fail on the next few they try to desulfate...

    I, personally, would not bet on a desulfator doing anything for your battery bank--But some folks say why not try and see if it helps--no harm if it does not work (other than a leak from your wallet to buy one--make sure you connect it correctly/to the correct battery voltage).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #5
    Re: Forklift Batteries
    fvrdbauer wrote: »
    I read the treads very interesting ,tell me how are they putting a 80amp charge on the battery?

    BIG battery chargers...

    Two of these would give 80a@24v:

    http://www.iotaengineering.com/dls2740.htm

    Or 4 of these would give 80a@48v:

    http://www.iotaengineering.com/dls4820.htm

    Some of the big inverter/chargers can put out 100a@12v - not sure if they can do the same amps at higher voltages.


    To get to the minimum 22a@30v that B.B. specified, you would need at least two of the 15a@48v units::

    http://www.iotaengineering.com/dls4815.htm


    The Iotas are 2-stage chargers, but they have a module called IQ that can plug in and turn them into 4-stage (3-stage+EQ).
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  • tallgirl
    tallgirl Solar Expert Posts: 413 ✭✭
    #6
    Re: Forklift Batteries

    What people forget when looking into desulfators is that the batteries are in bad shape when they need to be desulfated. Sulfation causes plates to swell and potentially warp. Also, the plates will shed more material than normal.

    The products =can= work, and I've recovered large numbers of batteries doing it, but they don't work magic. Batteries that have been sulfated multiple times are less likely than batteries that have been neglected fewer times to be recovered.

    When I first looking into desulfating batteries years ago, I used a Vector Smart Charger on my '79 Stingray battery. Then I used it on my daily driver. It managed to get more life out of the batteries than I'd ever gotten out of a car battery.
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