Flickr user Raw Sniper (aka ak Photographie) just sent in this great tip on creating a quick and dirty battery pack using an empty battery case and a few pieces of metal.

This can come in handy if you want to power a strobe from external power (or if you just need a 6V pack). So if the strobe goes weak, you just replace the external pack without fiddling with batteries.

If you use this as a system, you can keep a few in the bag, and once a pack is drained remove the batteries from it so you get a nice system to tell charged packs from empty packs (which will literally be empty).

The nice thing about this cell is that batteries are still charged individually using the same charger you already use. You can use this with regular batteries or with rechargeable, which end up being both cheaper and environment friendly.

To create this battery pack you will need five little metal strips (or thickly folded tin foil), 2 wires and strobe connectors (which RawSniper salvaged from an old hard drive connector, but a radio shack connector will do).

Place the batteries so they interchange in polarity Use three thin metal strips so they connect the batteries in serial Place the other two metal strips to provide contacts on the first and last batteries. make a small slit so the wires can go through the box. Attach the end terminals to the wires.

You are done in under 5 minutes :)

Of course, if you need a bigger battery pack you can either concatenate 4 cells packs or build an 8 pack.

P.S. if it is about constant power for the long run, try building an External Flash Power That Will Last Till Hell Freezes or Making a DSLR Battery Run 4 Times Longer