Charging voltage?

verdigo Solar Expert Posts: 428 ✭✭
So I borrowed a buddy's forklift charger. Its only a single stage charger but it does a 48 volt bank. My batteries are Interstate GC2XHD 232 ah golf cart batteries. As soon as I turned this thing on I could hear the batteries gassing, so I checked the voltage and this thing is kicking out 66 volts at about 10 or 11 amps. Temperature corrected (55 degrees) Interstate says 63 volts to equalize. I have been charging them off and on separated into 12 volt pairs, but I wanted to equalize them and check SOC with a hydrometer. Will the 66 volts harm the batteries with a one or two hour equalization charge?


  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: Charging voltage?

    Hi verdigo,

    Personally, I would not EQ my Flooded batteries above about 63.5 volts, even with cooler batteries than yours. Seems too aggressive to me. YMMV. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Charging voltage?

    The forklift charger is probably a "constant current" type. Against the relative small mass of those GC batteries it would push the Voltage very high under its output current requirements. Not a good idea to use this charger on small batteries.

    If you're going to do it, limit the time to 30 minutes at a stretch and watch the actual battery temp as well as electrolyte level. Too easy to overheat or lose water below plate level with very high Voltages.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Charging voltage?

    I have a set of Interstate GC2XHD batteries ( Green top ) and the hissing sound is normal for them at higher voltage, that said 66 volts is pushing the envelope a little. I'v used 32v on mine with no issues. They have pure lead plates that are very thin and temperature would be a issue so If I was going to use that charger, I'd be looking at it real close at battery level. As Coot said do it for 30 Minutes and give them a couple hours rest. There plenty of golf cart chargers that are constant current also with a timed charge.