hotbike

LED Projector by AviationMetalSmith, on Flickr
LED HOLIDAY PROJECTOR with 12 Volt LED's
I couldn't resist buying some of these at a 90% Discount Clearance Sale.
These are for projecting images of snowflakes and other holiday themes on the front exterior of a house.
The regular price was $24.99 , but at 90% off, they were $2.49. I bought six , and saved $135.00
This could be considered a sacrifice, since the device was never used before disassembly . Though the other five are intact, and much needs to be discarded to save weight, I plan to install this 4 LED COB device on one of my bikes, facing low downward of course, since I don't want to blind anyone.
LED Projector by AviationMetalSmith, on Flickr

LED Projector by AviationMetalSmith, on Flickr
HEAT SINK Steel Plate must remain, or the LED's will overheat. This is the back of the disc with the 4 LED's on the other side.
LED Projector by AviationMetalSmith, on Flickr

LED Projector by AviationMetalSmith, on Flickr

LED Projector by AviationMetalSmith, on Flickr

LED Projector by AviationMetalSmith, on Flickr

VegasTriker

Better plan on having one hell of a battery pack or expect a short run time. The size of the heat sink attached to the light indicates a large power draw. I know from experience that you can power 12V LEDs using a Li-ion backup battery intended for CCTV cameras. You can often get away with using four 18650 Li-ion batteries in series too without noticeable dimming. I built a couple of DIY bike lights this way but they were considerably lower drain that what you propose. A small battery pack that attaches to the light worked out fine but I really disliked the large battery packs that accompanied the 1 and 5 CREE XML-T6 bike headlights I bought. The cord was often in the way and for the 5 CREE light, the run time with an 8800 mAh 8.4V pack was awfully short. I have a variety of COB chips from 1W to 10W for DIY projects. The 10W COBs give off a lot of light but also produce a lot of heat just like high powered individual LEDs.

hotbike

Yes, I'm also using a smaller battery than ever before. Only 4 amp/hours, lead/acid. Last night's test run showed some considerable dimming after 90 minutes, but I haven't ruled out some other condition with the other lights or the battery.
The manufacturers spec sheet says the board contains four x 1 Watt LED's

I might have another problem with the temperature out in the garage being in the 0° to 10° range, having an effect on the charger. I might go back to a 7 a/h lead acid, but the local hobby store owner died (he was my neighbor, in fact) and I have to find a new source.

zebede

Looking forward to more reports on the workability and practicalness of this project. I find the concept extremely promising as a real-life safety measure. s. This sounds like it could be bright and project a large footprint.

hotbike

I've got it working, but one little detail was botched, the LED Driver Circuit, was 120 volt AC to 12 Volt DC... Since my bike battery is 12 volt, I left it out, but there are capacitors and stuff, that are supposed to regulate the DC, pulse it a little , to save electricity. The first project was to mount this first light in a tuna can, made a lens by cutting an old Compact Disc case with a Dremel, and hot melt gluing it together to waterproof it. Now the light is on my front left pannier, aimed straight DOWN, and wired to the same switch as the Brake Light (Red 2 watt LED) and the backup beeper. It worked well on Wednesdays ride , when traffic came up behind me, I flipped the switch and the new light was aimed directly at the fog line , the white line at the edge of the road.

I may be having trouble with the battery on account of the extreme cold , 0° to 10° F, and the fact that I started using a new 4 amp/hour battery. I might have to go back to using either a 7 amp/hour , or a 12 amp/hour battery, which I never had any problems with. But I think it was the extreme cold , which forced me to turn off two of the three headights after a 90 minute test on Tuesday night.

VegasTriker

Zombie thread resurrected after 5 years. I'm not sure how you intend to use these at a birthday party. If it is just to project something at the side of a house or inside, you would use the converter that comes with it to power the light and motor. These show up in second hand stores after Christmas as people unload decorations. Over the past 3 years I picked up several, rarely paying more than the OP did because mine came from the Goodwill outlet store where things sell for $1.89 per pound.

I never replied about using lead-acid batteries on a bike but that would be a big mistake. I tried that years ago when I came across plans for a DIY 10W headlight using a halogen bulb. It probably got used a dozen times after I got tired of having to charge the battery after each ride and the weight was horrible. Sealed Lead-Acid batteries are expensive too. Tough to mount a battery that is big and heavy on a bike. I can get the same lumen output today from an inexpensive, focusable, CREE T6 flashlight that uses a 3,300 mAh battery weighing 3 ounces. Flashlight + battery weighs under 6 ounces.