I was thinking of doing something to save myself a little money on my E-bike build.

I was thinking of installing 2- 15w EXLights (headlights) on my bike.

http://cgi.ebay.com/EXLIGHT-12V-15W-Bar-Mount-Halogen-Bike-Light-Assembly_W0QQitemZ150188479748QQihZ005QQcategoryZ22689QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksid Zp1638Q2em118Q2el1247

To do this, I was thinking of tapping into the main 48v 20ah LifePo4 motor battery with a cheap $30 48-12v DC converter. The converters are very small and light, and it would sure save on space, allowing me to have an extra waterbottle.

http://cgi.ebay.com/DC-to-DC-Converter-100W-48V-to-3-3V-12V-12V-Very-Nice_W0QQitemZ220249353100QQihZ012QQcategoryZ58288QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Can this be done?

If so, where would be the best place to tap into it?

I was going to set up a Crystalyte 5303 motor from Ebikes.ca, and use his remote shunt cycle analyst system.

Would instaling a DC converter be best before (battery side) or after the shunt?

I'm honestly not too sure.

Convertors add weight, inefficiency, and less reliability. There are a lot of 48 volt headlight bulbs out there that could attach directly to the battery. I googled PAR 36 48 volts and got both LED and Halogen bulbs.

ooooo. That's true.

I could even fashion my own with some aluminum conduit and such.

If that doesn't work, would a little converter be ok? It is soooo small....

The converter will work just fine . I use one on my trike that I bought off ebay for 3 dollars. Just wired it into the 36 volt output from the battery to the switch in my case. Works better than a 36v bulb because the voltage remains constant regardless of battery level so my lights remain bright instead of getting dimmer the faster I went with 36v bulbs (this might be more of a problem with sla's than the other expensive technologies)