Battery Blow-up

[crquisto]

I was doing some work in the engine compartment today and found one of my three batteries had blown itself to smitherines. The other two batts are bulged out on the sides. Clearly an overcharging issue, I'd say, but if anyone thinks otherwise, I'd like to know. Didn't have vinegar handy to neutralize the acid, so I diluted with a lot of water and vacuumed it out. Will spray with vinegar tomorrow. Initial thought was to replace all three batts and what I suspect is a faulty battery charger. However, in reading the manual, it says the battery selector should be switched between 1 and 2, and not left in BOTH because the charger can't correctly assess battery charge if it is. I bought it with BOTH selected and have always left it there. Before I dump $700+ into a battery charger, can anyone tell me: 1)is it likely a switchology problem (BOTH vs 1 or 2) caused this problem? And (2) how should I check my charger to see if it's bad?

[crquisto]

PS. Carver 405

[bud37]

Cant help with the charger but on your clean up.....vinegar is mildly acidic so won't be effective, so you need a base which would be baking soda, that will neutralize the acid spill from the battery, it will fizz up when it encounters acid....Mike

[crquisto]

Thanks, Bud37. No fizz, so I guess my wTer wash downs worked. On the charger, I called Charles Marine Electric tech support And got the lowdown on charger test. Also found out the charger can be refurbished if necessary go about a quarter the cost of a new one and that they haven't really changed much in the past 15 years.