Join Date: Apr 2006
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Re: Serious battery discharge
The batteries have taken permanent damage, BUT. It is very possible that you can recharge them (do a slow charge, not a fast one) and while you will have used up some of their lives, they may still be perfectly acceptable, i.e. 80-90% of the life may still be there. If you have a battery distributor nearby (where you bought them?) they are used to this type of thing, and you can usually bring the batteries in to them, where they will put them on an overnight or weekend charge and try to reform them for you. And of course, test what real capacity is left.
DIY or let them, but don't give up until you've taken a shot at it.
Then look online for a "Battery Brain" or similar. These are low-voltage cut-off relays, which will disconnect your batteries from all loads in the battery voltage drops to a set point, like 11.5 volts. Some come with a remote fob to reset them, some use a push button to reset them. Some claim to be "marine grade" but I think any of them might be of use.