If you completly deplete the house batteries, are they toast?

[daveshan]

You can generally pry the tops off of a "maintenance free" battery and check liquid level I do this to my camper's battery annually, the coach batteries have caps.

And to the OP, I completely discharged the group 31 battery in my Lance a few years ago. Was in a hurry and switched the refrigerator to 12v instead of off when I parked it then went wheeling for 7 hours, talk about dead!!

It came back just fine and doesn't even seem to be weaker than normal.

Best of luck
Dave

[wa8yxm]

Actually the answer kind of depends... Some folks insist there is no difference between a real Deep Cycle battery like the common Golf Car six volts often used in Motor homes and a Marine/Deep Cycle or starting battery.

Well, in the case of the last two (marine/Deep cycle and starting) they are right, there is not much difference.. but a real live deep cycle battery like the Interstate U-2200 (I hear it's got a new number now) GC-2 format, Golf car battery.... can survive such a goof, (Mine have and so has at least one other in this thread) it will take time off their total life, But they can survive.

A starting type, including Marine/Deep cycle... Not so well.

[BryanL]

re: "What if the house battery is a "maintenance free" one and the water level can't be checked.....(or can it?)"

sometimes it can but, usually, an overcharged sealed battery is a damaged battery. You can't do anything about the loss of electrolyte and that is why charging systems are more critical with sealed lead acid batteries than with wet cell types.

Sealed batteries do have pressure vents as a safety measure and they do usually have a technology that helps reduce electrolyte loss during charging. These help some.