Battery switch with shore power breaker

[Cadence]

Originally Posted by exMaggieDrum

I'm also confused by OP on the situation as described. After rereading it and the other posts I am guessing the real problem is that battery powered circuits on board the boat are "draining" the batteries when the shore power goes off - I assume because the shore power AC to DC battery charger quits. So basically the batteries aren't really powering anything in a significant way since they have very little capacity.

Turning off the shore power should have zip to do with the batteries running down, or at least, I have never seen a situation where that is the case. So if the shore power goes off it should be no different than if you turned off the shore power breaker manually.

You need to get good, adequately sized batteries that can handle X hours of no charging with whatever 12v loads you need to leave on in your absence (or even if you are there really). And just turn off the batteries at the battery switch when you leave. Turning off the shore power breaker should make no difference. May be I am missing something here?

If so you are not alone. The thing missing is does the day job require extended absences, weeks? Even if so I can't image shore power going out for extended periods. I seriously doubt it's the shore powers fault?

[mitiempo]

I agree with Mark as well. Your batteries have little capacity I would guess and should be replaced.

I do like Terra Nova's post though.

[smac999]

Originally Posted by MarkSF

What should happen, if the shore power goes out, is very little. Normally the only load on the batteries would be whatever is left on. If that's just the bilge pump, the batteries should last for months. If you have a 12V fridge, they should still last a lot longer than a day.

The real question is why your batteries rapidly go flat when they aren't being charged. You need to fix this problem, not try to invent a new kind of breaker.

Any decent charger will not flatten the batteries if the mains power is cut off. How is this different from a boat that's cruising away from the dock?

If you described your setup in a bit more detail, that would help. Type & number of batteries, type of charger, what's operating on the batteries, and so on.

My suspicion, though, is that your batteries are dead and won't hold a charge.

The above.