DIY LED Light Bar

[aomagman78]

I have some leftover LEDs from a previous project and I'm looking to make a light bar for my new ebike build. I've got some experience with LEDs and I was curious what other peoples experiences are on Ebikes. What do I need to look out for (vibrations, etc.) and what are some designs that have worked.

I have 10 or more of these LED Stars and the appropriate lenses to make them more of spotlights. I haven't decided whether or not to use thermal glue or screw-on for the stars. The LEDs are ~130lum and the lense will take 20% of that. I'm going to use 4 in series for a ~12V design, not sure how many I'll parallel.

I was also curious if anyone had devised a simple circuit for dimming the LEDs when the bike is not moving, at low speed or maybe when throttle is not applied. The purpose being that I can use a smaller heatsink if the lights are only burning bright when the bike is in motion. Has anyone else done something like this?

 

[llile]

I've messed around with these LED star boards a lot. they work well. Constant current driver is technically the best way to drive them, a small series resistor is less efficient but easy and cheap. Don't hook them direct to a battery, it go bang.

I've built several LED bike lights. The first was a Lots of LEDS (LOL) design, that took 8 rows of 3 5mm LEDs http://www.mouser.com/ProductDetail/TT-Electronics/OVLEW1CB9/?qs=qMBAYxCpqG8zqXYNg%2buZ6g== and mounted them on a PCB with some small series resistors (8 parallel, 3 series, with series resistor) to work pretty well at 12V. Very bright, doesn't focus very far. Drilled 24 1/4" holes in a cast aluminum box http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_11965_-1 and voila' bike headlights.


THe Stars work a lot better if you add a lens: http://www.jameco.com/webapp/wcs/st...&refineValue=FRAEN CORPORATION&from=mflisting There are several lenses that work for this.

Waterproofing can be simple - some hot glue is better than silicon rubber - holds up to UV very well, actually the same type compound is used to waterproof solar panels. Your hobby glue gun is actually an awesome waterproofing tool, whereas silicon rubber can have corrosive tendencies, and deteriorates in UV.

Unfortunately, a 500 lumen flashlight available at any hardware store is still an unbeatable bargain, and may be better than anything we can hack, since it has built-in optics, and some are watertight. I've hacked into them and made them run on external voltage, derived from the traction battery.

I also got an LED light made as part of a commercial motion sensor light. Crazy bright, with huge reflectors. TUrns out the thing ran on 12V so I hacked it to the front of my Ebike.

 

[llile]

Check to see if the back of the star board is electrically connected to the LED. Mine weren't and I just superglued them onto a big aluminum bar, they stay nice and cool.