I hate batteries .. Gearing up to fine tune some flash techinque. Got everything setup and even got so far as to get the flash balanced nicely with ambient. Then nothing ... Batteries in the flash gun died. Swap them out with fresh ones and one more pop to make sure things are working then ... nothing ('fresh' rechagables died after one pop). Swap out one flash for another with external AC power ... test pops OK ... nothing. Radio trigger battery died (don't carry a spare so dead in the water). No long sync cord ... no 'master' on camera flash ... dead. Moral of the story: Always use AC power and bring plenty of extra batteries anyway just in case. Always plan ahead and recharge the rechargables, etc. New project: AC power adapters to run everything.