How to use a camcorder battery to triple your DSLR's battery life
The new battery is bulky, but it provides almost 4x the shooting time as the stock one. And yes, I know, my soldering technique needs some work.
I’ve gotten interested in star trail photography recently, but the stock battery on my Canon SL1 only provided 2 hours of shooting time and I needed at least 6. I made a trip to RadioShack in search of a solution.
In my electrical engineering naivete, I assumed that I could use my USB backup battery to power the camera. One of the associates informed me that USB only provides 5 volts, when my camera required 7.4. He did suggest, however, that I look into using a camcorder battery. They tend to have much higher capacity than DSLR batteries and provide the same voltage.
As it turned out, I had an old camcorder lying around, so I pulled the battery out to use, soldered some leads onto it, and used the battery adapter from an AC adapter kit to attach it to the camera. I tested the battery a few nights later and it lasted for almost 8 hours. Problem solved.