Quote:
Originally Posted by ThreeCW
After a full charge, it takes lead acid batteries 12 to 24 hours for the voltage to stabilize
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Quote:
Originally Posted by GordonInFla
I charged over night and pulled my meter out and all battery's were 6.4 except one was 4.3
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After a full charge, it takes lead acid batteries 12 to 24 hours for the voltage to stabilize ... the key here is to fully charge the battery pack, disconnect the charger and wait the full 24 hours for the battery voltages to stabilize. If you are reading 6.4 volts at let's say 1 hour after charging, you are not getting a representative full charge voltage and you will think that your batteries are at a higher state of charge than that actually are. See the attached State of Charge Chart for more information.
I have personally done what you are proposing ... except my cart was new to me and I had no idea how the previous owner had maintained the 8 pieces of 6 volt US Batteries that were in the cart when I bought it. I had one battery fail, with a shorted cell and about 4.1 volts if I recall correctly. I replace the failed battery with a "blemished" golf cart battery and got another year or so from the pack. I think it was worth the $100 for a years worth of carting ... I was new to carts and wasn't too keen to renew the full pack.
A year later when the next battery went, it failed when under load. The static voltage was only 6.01 volts, when slow starting on a level gravel road it was 2 to 4 volts, uphill it was 1.3 to 1.4 volts and on a steeper hill it was 0.2 to 0 volts. At this point, I replace the pack with 8 pieces of 6V Trojan T-125 batteries which I have been using since July 2018.
Before you decide on replacing 1 or all 7 of your 42 volt battery pack, if your failed battery still allows you to run your cart, I would suggest load testing your entire pack. The cart itself is the best load tester you can get. Set up your multimeter leads with clamps and test each battery in your pack (one at a time) from a standing start and record what the "static" and the "under load" voltage is. If you can do it on a hill even better, but test each battery under the same load conditions (same acceleration rate and same hill load). You can post the results in the forum and we could possibly guide you in determining if your battery pack is worth keeping (with one battery replacement ... or more) or if you should replace your whole pack.
I have also attached a few photos of the battery testing lead that I built for load testing my battery pack.