I have a 2002 Gem 4 seater E825 that I am having issues with I bought 6 brand new Trojan batteries and put in it just this month. I charge it up and it reads 85(%) I’m assuming as it really doesn’t tell you other than flashes under the battery indicator. I do not have a manual for this thing. When it’s charged it runs nicely however it seems to discharge very fast after just a mile or so of driving it. Also as its running all of a sudden there is a constant beep or hum while driving it. The battery indicator seems to loose voltage very fast while driving. I checked voltage on all batteries and there all nearly 13 V. Is there a reason why the batteries don’t charge at 100%? is this normal? I’m trying to sell it and this don’t help!
Batteries fully charged will be about 13.8 volts just off the charger. Sounds like your charger is on a Gel algorithm and you have flooded batteries. Check chemistry with a hygrometer, should be 12.65+ when fully charged.
Under charging flooded batteries will result in 50% loss of range in 6 months.