I have an older gem from 2003. The gel battery pack is too far drained to be recharged. If I call for a repair, they'll charge $225. Is this something I can do and with what tools? Thanks.(More info, 10 points.)
Most batteries only last a couple of years.
The batteries have a LOT of power in them and can explode or take out your face or a finger if you do anything wrong. some of my friends in the EV trade have experienced this. Safety is the biggest issue, and Lead battery safety cant be explained in an answers format. sorry
The Gem uses 12 V deep cycle Trojan batteries wired up to provide 48 V . That means there are four of these batteries in series, more may be in parallel with these four but basically chances are only one of these batteries has failed. If you run a voltmeter across each battery, you should be able to identify the bad one fairly quickly, then it's just a matter of replacing that 12 V battery with a 12 V lead acid, AGM, or gel battery with the same size, terminals and capacity. The capacities ranges from 130 AH to 150 AH. An actual new Trojan battery would run about $190 (without a rebate for the old one and you can usually get a rebate) but chances are you could get a used one for less or some other lead acid battery with similar dimensions (roughly 14 x 7 x 11 ) and capacity ratings for less. Gel and AGM batteries are sealed but if you were willing to break the seal (dangerous as it contains hydrochloric acid), it would be possible to drain the acid, clean the mats, file down the plates, reassemble and add new acid to rebuild the battery. You may be able to find someone who does this and can sell you a reconditioned battery. Once you isolate the failed battery with a voltmeter, you could try charging it individually (sometimes a battery won't charge because other batteries in the series are already at full charge). You may even be able to bring a dead battery back to life by trickle charging and pulsing reverse polarity through it to break up the sulfate buildup on the plates. It's probably a good idea to periodically break up the battery pack and charge each battery separately to try and get as much charge into each one as possible. Chances are, the tools needed would be the same tools you would need to change out a car battery except that these batteries are heavier.
