maintained emergency lights

My alarm battery lasts at least 4 days. As determined by experience. :o(

As Dave points out, it is the houses in darkness they target, not the ones with the lights. Sorry for the slightly ambiguous wording.

Colin Bignell

Nowhere near even that. An 8W fluorescent emergency light runs at a ballast factor of about 0.25, which means it's running the tube at 2W. If you look at the battery capacity in Whrs, you'll quickly see they can't supply 8W for anything like 3 hours.

It's fine for emergency use, i.e. finding the exit, which is what it's designed for. It will be fine for lighting up the consumer unit providing it's not too far away and in direct line of sight.

I bet there are a significant number of alarm systems that have knackered backup batteries that either won't maintain the alarm at all or only for a short while. At least if the one in the sounder is also knackered no one will be any the wiser, even the householder.

Unfortunately round here it seems all the batteries in the sounders are fine but the ones in the main units have had it, so any power cut starts a cacophony of alarms.

Sorry, I completely misunderstood: I thought they were going to the lit houses!

I have now read the old thread about power consumption. For comparison, if you had something like a car battery charger, car battery, and 12v lights, how many watts would the charger draw whilst topping up a lead acid battery on a trickle charge? More or less than

Thanks.

Well 6W is 500mA @ 12v. You'd not want to have a car battery on long term trickle charge at that rate, it would gas summat rotten. 100mA or less is more reasonable (1.2W) but you'd have to take into account ineffciencies in the charger. If it's a lump of iron wrapped in copper that could use a few watts just plugged in.

So overall it could be less as you'd only have one thing conected to the mains but then there is the complication of LV wiring for the lights. At

Thanks (I've only just seen this post as my NR was playing up).