I am sorry to hear that. Were you motoring or sailing? If you were motoring, have you checked your regulator on the alternator? Maybe you were overcharging?
When you charge batteries you have to go through several phases (1, charge max, 2. lower amount, 3 trickle charge). If your charger/your alternator, windvane or sun panels faile to lower the charge, then you fry the batteries.
John Bernard "JB" Duler
Meltem # 19, Western Med