I am figuring out how to keep the batteries charged while living aboard during the winter here in the UK. My boat is strictly a 12 Volt system. Our solar panels usually are all we need, but they're not going to cut it when the days get short and rainy. I need to buy a 220V battery charger to maintain our 480 AH house batteries. My battery bank is probably overkill - we got by just fine with 280 AH on our last trip, but I thought it would be prudent to have the greater capacity so I doubled the bank. I'm learning that means we may now need a bigger charging capacity in order to keep the batteries in good condition.

I've found a charger that will run on both 110V and 220V. I would wire it with a regular British plug to plug into the same power strip that our heater plugs into on a 16A cord from the dock. The charger is a 3-stage that will protect and maintain the batteries, according to the manufacturer. The dealer I spoke with today recommended a 40A unit, due to the size of my battery bank. But given our modest power usage (typically ~80 Amps per day) that seems like overkill. I am leaning towards the 25A unit.

I'm still researching the issue, but does anyone have any particular comment on the above? The unit I'm looking at is linked below:

http://www.advanceyacht.co.uk/products/power-management/battery-chargers/12v-battery-chargers/cristec-cps3-12-25.html

As an aside, my original plan had been to buy a sacrificial 12V battery and a cheap automotive battery charger, and run everything through that for the winter (completely disconnecting/protecting my house batteries). But it seems to make more sense to buy a decent charger, and one that could be used back in the US if needed.