Automatic Emergency Lighting.
Oct 8, 2013 3:47:11 GMT
Post by Deleted on Oct 8, 2013 3:47:11 GMT
Some members may be interested to see a project that I constructed several years ago, when living in an area that was blackout prone.
It came in very handy a couple of weeks back when we had a 90 minute blackout caused by very strong winds.
It is an Auto Emergency light, powered by a 12V 7.2AH SLA battery. The original uses a a couple of 1Watt Star LEDs in a diecast aluminium case, with an internal constant current source.
Back when it was originally made, typical 1W White Star LEDs were only about 35 lumens brightness, yet it was more than adequate when placed on the top shelf of a kitchen cupboard., even giving enough light for the main living room for moving around. I have the control box sitting on top of the fridge, which is directly below. It automatically comes on about 4 seconds after a power failure, so no fumbling around for a torch or candles.
These days you can buy genuine Cree brand 3W white LEDs on ebay, that have about 3 times the light output, even when run at 1W.
They can be obtained for as little as 5 for $9 including postage !
I am using 3 of those in a similar diecast case as a supplementary light for the problematic fluoro in the bathroom. However, that one is powered by a DC SMPS plugpack that I had laying around,
and uses a PW5 resistor mounted on an internal 5 pin tagstrip to drop the voltage so that the LEDs are driven at about 600mA instead of their maximum 700mA.
The controller for the emergency lighting uses a Silicon Chip designed SLA battery charger supplied by 15V AC from a toroidal transformer that I had laying around, with 2 x 7.5V AC windings connected in series.
Our blackouts rarely last more than 90 minutes, but when the LEDs are run at only 300mA, many hours of emergency lighting is available.
The SLA Charger kit sells for about $30 from Altronics. (K-1695)
Alex
P.S.
I intend replacing the existing 1W LEDS with 2 x 3W Cree LEDs when they arrive in a few weeks time. I will run them at the existing 350mA though, to ensure that the lighting will last for many more hours in the event of a lengthy power failure.
Uploaded with ImageShack.us
It came in very handy a couple of weeks back when we had a 90 minute blackout caused by very strong winds.
It is an Auto Emergency light, powered by a 12V 7.2AH SLA battery. The original uses a a couple of 1Watt Star LEDs in a diecast aluminium case, with an internal constant current source.
Back when it was originally made, typical 1W White Star LEDs were only about 35 lumens brightness, yet it was more than adequate when placed on the top shelf of a kitchen cupboard., even giving enough light for the main living room for moving around. I have the control box sitting on top of the fridge, which is directly below. It automatically comes on about 4 seconds after a power failure, so no fumbling around for a torch or candles.
These days you can buy genuine Cree brand 3W white LEDs on ebay, that have about 3 times the light output, even when run at 1W.
They can be obtained for as little as 5 for $9 including postage !
I am using 3 of those in a similar diecast case as a supplementary light for the problematic fluoro in the bathroom. However, that one is powered by a DC SMPS plugpack that I had laying around,
and uses a PW5 resistor mounted on an internal 5 pin tagstrip to drop the voltage so that the LEDs are driven at about 600mA instead of their maximum 700mA.
The controller for the emergency lighting uses a Silicon Chip designed SLA battery charger supplied by 15V AC from a toroidal transformer that I had laying around, with 2 x 7.5V AC windings connected in series.
Our blackouts rarely last more than 90 minutes, but when the LEDs are run at only 300mA, many hours of emergency lighting is available.
The SLA Charger kit sells for about $30 from Altronics. (K-1695)
Alex
P.S.
I intend replacing the existing 1W LEDS with 2 x 3W Cree LEDs when they arrive in a few weeks time. I will run them at the existing 350mA though, to ensure that the lighting will last for many more hours in the event of a lengthy power failure.
Uploaded with ImageShack.us