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Not quite blackouts or emergency lighting but interesting alternative perhaps

mapj1

Sort of related to other posts about power cuts but not quite,

I recently have had my attention drawn to the 'Blackout bulb' A normal looking LED lamp for a Bayonet or ES holder, but with a battery inside. When mains is present it lights normally and charges the internal battery. If mains is cut and the bulb 'sees' a  high impedance, such as a normal light switch, then it goes off. So far so good, now the clever part..

If the supply fails, but there is a low enough resistance between the terminals, such as in a power cut, when other loads will be in parallel, then the light comes on using the internal battery (*). Claims to run for up to 3 hours.

I can see a use for these to retrofit for  landing lights and similar places where an EM fitting may  not be that convenient.

Has anyone else used them  yet ?

Would anyone dare suggest they could replace normal EM fittings ?

Mike.

(*) a moist finger is enough to get it started and you can use it as a hand held lantern

  • Humm - interesting idea. Presumably less useful where you have several lamps on the one switch though.

    I wonder if long switch drops might fool it too (shared of the low energy lamp flicker when off problem), if it uses a.c. for sensing. Or the effect on RCDs if it uses d.c.

        - Andy.

  • Yes, I purchased several of these some years ago on fleabay.

    They worked as claimed initially but reliability was very poor, none of them lasted more than a year. Note that they only work on a switch dedicated to THAT LAMP ONLY.  They wont work reliably on a switch that controls several lamps.

    Not a suitable replacement for standard self contained emergency lights. Not reliable enough, and risk of being replaced with ordinary bulbs.

  • Should be fine on an RCD. DC from the internal battery is used for sensing. The current is minute. Not measured, but observe that leakage via skin contact is enough to turn the light on. Also the current goes "out" along one wire and "returns" via the other wire and therefore produces no net magnetic field.

  • I never heard of them

    Certainly very interesting

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