One of the ways to increase the time a strobe or a camera can run for a longer durations, is to use an external battery for power. Some cameras and strobes have a dedicated port for receiving external power, and some don’t. But even if they do, the device that provides power is usually a propitiatory one and only fits one specific device, so the cable to power an SB800 is different than the cable you’d use for, say, a Canon EX strobe (assuming you have both :)
There is a solution to get around this power problem. Use whatever external power you can source with the built in battery chamber, mimicking a battery set. The options we shared before involved crafting a wooden dowel to fit the exact size of a battery, or using uncommon electrical connectors for the same end.
Reader Jake Carvey just shared a cool tip regarding this method with us. One that made me slam my head into the table. Jake suggested using battery upsizers for mimicking the internal batteries, eliminating the need of a wooden dowel.
Originally, battery upsizers are used for converting the form factor of AAA batteries to the bigger AA size. Or making an AA as fat as a D cell. The amount of juice in the battery stays the same, but it can be fitted in a bigger compartment.
The idea is simple; solder a connector to the inner part of an upsizer and you can connect it to whatever power source you wish. Of course any power you feed into a strobe or a camera has to be regulated, controlled and preferably fused (see the build links above). Once you decide on the power option, you can instantly fit it in any device that accepts AA batteries.
[Ziotek Upsizers tip by Jake Carvey]