My first go at making an adapter didn't work, see this post. The original UBEC I chose didn't output enough voltage, so the head unit thought it was dealing with a flat battery.
So, I ordered a UBEC from hobbyking that outputs 7.2 volts, for a low, low price of $5.04 + shipping.
I finally had a few minutes to solder up the new UBEC and see if it works... For a cable, I cut the wires off of an old and dead Niterider pack. If you don't have that available, you can go to Radioshack and pick up some DC power connectors and make your own cable. Just be sure to bring your head unit with to make sure you get the right connectors. Also take care to get the polarity right.... otherwise you'll have more smoke!
Make sure to place any heatshrink you want to use on the wires before you solder them together!
|Soldering UBEC output to Niterider cable|
|Niterider connection on the left, EC3 battery connector on the right|
Before I placed the heatshrink, I tested the system out:
|Let there be light!|