Bright lights!
Two of these: MPJA # 31325 OP "1000 Lumen, 10W, Super Bright, Cool White LED Module" running at 1/2 power outperform two of these: 20 Watt, 24 Inch T12 Cool White Fluorescent Bulb, in my garage. I haven't measured it, but everyone who has seen A/B testing (fluorescent vs LED modules) said "wow, that's much brighter" when the LEDs were on and the fluorescent off. The A/B testing was looking at the floor, not at the modules or the fluorescent tubes.
Here's the details:
I had to replace my old wood garage door. The new steel door looks good, but when open it blocks the ceiling fluorescent (24", 2 bulb) fixture. (The windows in the old door let the light shine through to the floor when the door is up, but the windows in the new door don't line up with the light.)
I installed 10W no-name LED modules (MPJA # 31325 OP "1000 Lumen,
10W, Super Bright, Cool White LED Module") on the inside of the door (the side the faces the garage floor when the door is open) on the center frame members of 2 door panels. The steel frame member is an L shaped 18" long and 2 1/2" wide on one leg of the L, and 2" wide on the other, and is welded to the steel door panel. It's essentially an infinite (but inefficient) heat sink. I hung 2 copper braids made from coaxial cable shield from the ceiling and ran 12.7 volts DC to them. I built a T out of wood and 2 copper (1/2 dia) pipes and installed it on the top panel of the door. When the door is about 2 inches from fully open the copper pipes on the T contact the hanging copper braid. Wires from the pipes on the T connect to the LED modules mounted on two door panel center framing members.copper copper ==+=== ===+== -------------- | | | | ----------- | | |wood| | | | | | | | | | | ---- | | | door | | | | +-module-+ | . | | . . +-module-+ . . . | | -------------------------------------
I did this to power them:
1N5406 Diodes +12.7V---+---[.5R]--->|--->|--->|--->|---+---[Module]---+ | | | +------[6.8R]---[3V Relay]------+---[Module]---+ | Gnd-----------------------------------------------------+That drops about 3.9 volts across the resistor and diodes, energizes the 3 volt relay, and delivers about 8.9V to the door mounted modules. They run at a little less than 5 watts each and are bright bright bright!
When the door goes up and the fluorescent light is blocked, the LED modules mounted on the door automatically turn on, and provide more light - a lot more light - than the two 24" fluorescent tubes do when the door is not blocking them.
I was so impressed by the increase in light that I built a "fixture" containing two of the LED modules and mounted it on the ceiling. The "fixture" is just a 36" x 2" x 1/8" aluminum bar with the modules screwed to it and separated by 24". It provides the needed heat sink for the modules.
When the door is closed, the relay transfers power to the ceiling modules instead of the modules mounted on the door. The ceiling modules have the same voltage dropping circuit as above, but without the relay.
The ceiling fluorescent light switch also controls a receptacle, and the 12V power supply is plugged in to that, so when the ceiling light is switched off the LED modules are also off. For A/B testing I plug the power supply into a different receptacle.
The lighting now is far better than it ever was. I get a 15 degree C temperature rise, measured at the module wiring terminal on both the door and ceiling modules, after 2 hours of continuous operation. The datasheet I found says 60 C max, so they should be ok even on the hottest days.
I owe thanks to Jon Elson whose post about replacing his fluorescents with LEDs gave me the impetus to experiment.
Ed