ebike lighting/12v accessories on the cheap

With any electric vehicle, power reserves are of paramount importance - every watt counts. Lighting can be a power hog, particularly if it's spiffy halogens so they're often out of the question. Problem is while 12v DC lighting & accessories are plentiful and inexpensive... anything other than 12v gets tricky with a limited selection & often skyrocketing costs.

So after some shopping around I got a pair of LED MR16 Halogen replacement cool white spotlights (12V 4W/440 Lumen - 50 Watt Equivalent) to play with, one with a 30° beam angle (high beam);



http://www.amazon.com/gp/product/B005YUS7FG/ref=oh_details_o00_s00_i01 $4.99

and one with a 60° (low beam);
http://www.amazon.com/gp/product/B005YUVP9G/ref=oh_details_o00_s00_i00 $4.99

Conveniently for me, they just fit in the old headlight from my now stripped Schwinn (it's one of Norm's wonderful bullet housings), so I stuck the 30° beam one in there;



...but if you're not fortunate enough to just happen to have a 2" housing & bezel kickin' around you can get crafty and make a mount for just the bulb itself w/o a housing (it's completely sealed ofc) or you could get a set of something like these driving lights & just pull the greedy 55w halogen out of it;

http://www.walmart.com/ip/Driving-Light-Kit/16680058 $18.98 pair

Ofc you'll need to use a DC to DC step down converter to power it, which one exactly depends on your battery pack voltage... but there's plenty to choose from w/a lil bit of hunting around on ebay or wherever. I've gotten this one for my 48v pack;



http://www.ebay.com/itm/DC-DC-Conve...462?pt=LH_DefaultDomain_0&hash=item1c25d40226 $17.59

...and it's a nice enough lil unit for the money & I've had no problems w/it - but if you'd like a somewhat better one they're quite common w/various input voltage options for the electric golf cart application. Here's an example of a 48v to 12 unit;

http://www.ebay.com/itm/48V-to-12V-...cer-/150850732934?hash=item231f678386&vxp=mtr $39.99

For the LED taillight a simple trim/marker light will do nicely, they're commonly available at most auto parts stores and are quite inexpensive. I've this lil one for example;



http://www.amazon.com/Clean-Blazer-...?s=automotive&ie=UTF8&qid=1342071006&sr=1-111 $6.99

There's some peripheral efficiency loss w/e you use a converter, so the consumption wouldn't be as ideal as using 48v lights, but the loss is marginal - very marginal when you consider what 48v LEDs cost & their limited selection & availability lol

A power supply/charging dock tapping off the 48 to 12v converter is now a piece of cake - already wired up to power the 12v DC LED head & taillight, it's a simple matter of buying a cheap car cigarette lighter adapter with 2 USB ports, busting it open to cut the dealie off the back & resolder better wires to it & sticking it back together again - there's plenty to choose from but here's one for an example;

http://www.amazon.com/Wagan-Twin-Socket-Travelers-Adapter/dp/B0019891NO/ref=lh_ni_t $11.31

I added a main power switch so I can easily shut the whole thing down, but I used a flush face switch (scavenged out of a PC power supply) so it doesn't so easily shut itself down bouncing around in a pannier with w/e crap might be in there. As I had no pretty lil project box I just did a variant of the "duct tape pack" like the custom LiFePO4s have - but this time a "patented" cable tie pack method lol;



It ain't pretty, but it was easy to make, safe & works a treat - and best yet I can charge any kind of small battery like for my GPS, camera or whatever, listen to tunes w/the MP3 player charging (the speakers are USB powered too) and I don't even hafta worry about the lame battery in my netbook any more, plug & play FTW


As always the links & pricing are just examples and are not always exactly what I've used or from a known, reputable vendor - shop around, you'll prolly be able to find better for less...