Yeah, check each battery voltage. I’m no expect on this I just checked each battery and mine were at 12.51 excect for my newer battery which is holding 12.68 (100% charge). And the car is reporting 80 percent so that’s about right. I suspect my charger is not peaking the packs right as it’s not set for flooded but I’m no expert on modifying them so I’ll have to replace the charger. For now I’m going to charge individually each battery for 1 hour on 20 amp setting each. The charger actually sets the amps accordingly, I saw it was at 8 amps for awhile then dropped to 3 or 4 for the last 20 minutes or so. The charger isn’t topping them off. I tried charging one battery but I checked voltage at other batteries and they remained the same or dropped a bit, so I don’t think what you’re saying is really happening. You’re just charging up one battery and that’s effecting the overall voltage but not each battery voltage. Test by charging one battery and checking voltage at the other batteries.
Not sure if this is right for GEM’s but here’s a voltage chart. Seems to match up with what my indicator on car is reporting.
I’m resting on 12.51-12.58 on 5 batteries and new battery is 12.68. I hope the charger hasn’t ruined the other 5 already.
Now I’m really confused. I have each battery holding charge at least 12.6-12.67 now using external charger so I should have around 90 percent charge or more but the car indicates 75 percent. I give up!
Good info. From what I gather from this forum and experience with chargers with % charge indicators, the percent charge is, at best, only directionally correct. Never got my car’s meter to indicate over 80% using on board charger. Using regular auto charger on individual batteries with the cutoff switch OFF, it always read 100%. Same when I charged the pack with the regular auto charger connected to one battery but with the cutoff switch ON. This is supposed to be impossible, but is what I have observed on numerous tests. I am confused, too, but that seems to be a natural state when dealing with GEM cars with issues. I’m installing a volt meter on my car and ignoring the one on the dash gauge. Unless someone has a better alternative???
I’m thinking my batteries at a year old just can’t hold 100 percent charge any longer. Should probably have the Trojans but I’m too cheap to pay that much for batteries. Could be the charger is not set right. If I was more mechanically inclined I’d convert to a gas motor, but I’ll probably just sell it here at some point. There isn’t much support on these, have to drive 2.5 hours away to have it serviced. It’s fun driving in the summer but I’m not sure I can justify keeping it with the charging issues and battery replacement. That negates any savings you get over fuel.
If your batteries are a year old and not able to charge to 100% its almost a sure bet your charger is not set to the right algorithm.’'This is most prevalent when your batteries are flooded or AGM and the charger is set up for GEL’s . AGM and Flooded should have charger set to 13 GEL setting is 14.
A fully charged battery pack in a GEM will be 80 plus volts NOT 72.5
Sorry,
“B” refers to battery.
Batteries have two terminals. Positive (B+) and negative (B-).
Each battery is considered to be 12 volts nominal. Measured from B+ to B-.
Gems use 6 batteries connected in a series string. Jumpers connect batteries positive of one to negative of the next
Voltage adds in series for 72 volts total.
The negative terminal is available for connection on one end of the string and the positive on the other end.
Of the total 72 volt pack, B- refers to the negative of the first battery. B+ is the positive terminal of the last battery.
Hello Inwo - From reading discussions from other people with problems similar to mine I thought you would be the best person to talk to for advice. I have 2000 Gem e825 with an original Schott charger that I must replace. I have new Trojan 30 XHS water/acid batteries. I would like to get a new charger that I can install under the dash where the Schott is and that can connect to the green charging light on the steering wheel. It looks like the Delta Q may be what I’m looking for but I do not know enough about the different models to make an educated decision. Someone wrote you sell batteries and I would like to know your opinion and whether you carry a battery that I can use.
Thanks - Thom