Matt's Awesome Stuff
Plug-in Power Adapter for Canon Camera
Last updated: 16Apr2012
Back in 2007 someone gave me their old Canon digital camera. It used a Lithium Ion battery but the battery was old and barely held a charge. Since I was using it mostly to document projects I didn't need an actual battery, I just needed power. So I built a fake battery power supply that plugged into the wall or USB.
A DC voltage is a DC voltage, it doesn't matter the source. A lithium ion battery starts around 4.2V and drops to about 2.7V before it shuts down. Anything in that range should work. USB is 5V, which might be fine, might be too high, so I played it safe and connected two diodes in series. They drop 0.7V each, so, it should be 3.6V. Then I added the capacitor to help supply power when the focus motor surges. I have a USB wall plug too, so I can power it off any outlet.
I was expecting to cut a hole in the case somewhere for the cord and plug, but as it turns out, I was reinventing the wheel. Canon cameras actually have these fake battery things as a real accessory. It's why they don't have a DC power port, and why there happens to be a removable rubber plug underneath the battery door.
I built the fake battery adapter out of plastic from a VCR carcass. Cut it apart with a dremel, sealed it with hot glue. Sometimes I wish I could try out prison, just to have a chance to explore my resourcefulness.
Ugly but functional. Should be my motto. This should work with any battery, disposable or rechargeable. Just match the voltage.