maintained emergency lights

[chrisj.doran]

I'd have expected the current to tail off too, but it doesn't.

The thread is here:

or My results are at post no 18.

I didn't try removing the rather bright LEDs, which might have a bit to do with it. The LED does perform an additional purpose -- it's so bright that you can see your was to the loo in the dark without turning on the blinding 100W landing light, but I doubt whether that saves its overall cost in leccy.

As to whether burglars burgle more in power cuts, are there any statistics? I'd have thought that there was a good chance of finding a householder and fierce dog sitting by a candle behind drawn curtains.

Chris

[Huge]

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

[nightjar]

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

[Andrew Gabriel]

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.

[Dave Liquorice]

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.

[Andy Burns]

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.

[Stephen]

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

8w?

Thanks.

[Dave Liquorice]

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

12v volt drops due to cable resistance and currents delivering real power are significant.

[Mark]

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