it's called boiling mine did it to. i think it happaens when you overfill the batts or don't charge before adding the water. after doing it twice (and spilling water) i think they got to the correct level as they have stopped.no noticeable damage to cart other than a little corroshon on the frame but mines a club car with an aluminum frame i don't think you'll have to worry about that as much(if at all) with an ezgo it's all explaned in
club car elec under what happend. hope this helps.
2000 yamaha G-16 gas (now nephew's)
2007 EZGO ST450 custom in viper blue and 2k in mods.
and 2007 starcar elec (for mom)
no longer cartless..........he he