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!g). ;-)

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

On Tue, 09 May 2006 20:59:03 +0100, Owain
wrote:

T i m wrote:
Anyone aware of a an 'emergency' light that (ideally that functions
like a std 5' flouro) that would:

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

Ah, interesting (link please)?

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

They all do ;-)

Normally anyway ;-)

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

Aha.

Thought so .. ;-(

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.

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)?

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.

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

Or 240v relay tucked away somewhere ..

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

A not uncommon requirement,

That's what I thought .. shrug

but you have to be careful over the
implementation if you have safety regulations to comply with.

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

T i m brought next idea :
Anyone aware of a an 'emergency' light that (ideally that functions
like a std 5' flouro) that would:

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

Stay on when 'on' and the power fails.

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


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

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.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Tue, 09 May 2006 22:54:58 +0100, Harry Bloomfield
wrote:

T i m brought next idea :
Anyone aware of a an 'emergency' light that (ideally that functions
like a std 5' flouro) that would:

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

Stay on when 'on' and the power fails.

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

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

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

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.

Ok, ok .. I getcha ..

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.

Ok ..

Problem- The diode would drop around 0.7v - so the charge would be less
than optimum except when the lights are turned on.

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?

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(?).

Hmm ..

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.

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

T i m wrote:
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!g). ;-)

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


UPS... ordinary light fitting.


NT

On 11 May 2006 02:58:12 -0700, wrote:

T i m wrote:
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!g). ;-)

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


UPS... ordinary light fitting.

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

Thanks ..

T i m