Maintained, non-maintained or non-existant?

[T i m]

Hi All,

Anyone aware of a an 'emergency' light that (ideally that functions like a std 5' flouro) that would:

Come on when turned on (no!). ;-)

Stay on when 'on' and the power fails.

Not to come on when 'off' when the power fails (tricky one huh) ;-)

By 'on' and 'off' I would like to think as seamlessly working with a batch of other flouros in my garage. It can have it's own unswitched feed plus a feed from the switched lighting cct.

I have thought I could do something with a relay but that would probably render the light unit 'out of spec' (FWTW)?

So, your go .. ;-)

All the best ..

T i m

[Owain]

You can get ELU packs for converting existing luminaires. The amount of battery you need is a function of wattage and desired run time.

They all do ;-)

The easiest way of arranging that would be to have a DP light switch, one pole switching the main lights and the other pole switching the output of the ELU pack.

It would probably need a volt-free switch for controlling the battery side of things.

A not uncommon requirement, but you have to be careful over the implementation if you have safety regulations to comply with.

Owain

[T i m]

Ah, interesting (link please)?

Normally anyway ;-)

Thought so .. ;-(

Oh, ok .. sorta follow that .. even if the 'charge' input to the ELU fails the output goes nowhere (even though it's trying to light the light)?

Or 240v relay tucked away somewhere ..

That's what I thought ..

Don't 'safety regulations' apply even if you just want to scratch yer ar$e these days? (or do you mean if it's a public place etc)?

All the best ..

T i m

[Harry Bloomfield]

T i m brought next idea :

A standard 'Maintained' emergency light fitting would do both of the above.

A rather dangerous way to do it, but a relay wired between the 'always live' and the switch wire would only operate when the light switch was off and could be used to inhibit the discharge of the battery via the light - a normally closed contact pair in the +ve battery lead. Problem is that it should not interrupt the charging circuit of the battery - now if we add a diode across those contacts (around 50v 3amp), diode arrow pointing to the +ve on the battery that would allow it to charge.

Problem- The diode would drop around 0.7v - so the charge would be less than optimum except when the lights are turned on. A suitably chosen value of resistor in series with the diode, high enough that under short discharge conditions it presented almost no load on the battery, but under charge helped overcome the 0.7v drop of the diode perhaps(?).

The higher the voltage of the battery, the less the voltage drop would matter. The diode would be shorted out if the power failed, so there would be full output under power fail conditions.

[Owain]

These people do lots of stuff:

modules fitted conversion unit of course our old favourites, TLC >The easiest way of arranging that would be to have a DP light switch,

Quite possibly

Yes. Or Health And Safety At Work etc.

Owain

[T i m]

Ok, I've got a 18" one now so I can play a bit ..

Ok, ok .. I getcha ..

These charger are normally not that accurate are they Harry, neither constant voltage nor current and just relying on the 'softness' of the cct to stop overcharge?

Ok, thanks for that and food for thought.

I might just install it as_is and put up with the odd time when the power fails and I'm not in the garage (so wouldn't need the light).

Are there more fancy versions with opto sensors that stop the light coming on in daylight (even if the power fails)?

All the best ..

T i m

[meow2222]

UPS... ordinary light fitting.

NT

[T i m]

Hmm, now there's a bit of lateral thinking .. and I happen to have a couple spare .. ;-)

Thanks ..

T i m