On Sat, 17 Jun 2006 17:50:33 +0100, Dave Plowman (News) wrote:

In article ,
Alec wrote:
I have a customer with a small chalet with no electricity. I fitted a
basic domestic alarm connected to a 75 ah leisure battery.

Why so large?

You can realistically only draw around 35% of total capacity, so it's
functionally a 25AH battery. It's probably oversized, I would guess that
the actual requirement is closer to 8-10AH, but at least it will give some
headroom for a couple of days power outage.