Depending on how well you keep the Sanyos charged, you could be using the batteries backwards: the non-Eneloops might be rated at 2700mAh, but if they haven't been charged in a week or more, they might provide less results to your flashes than the Eneloops would.


Regarding your question about the Canon power pack, CP-E4, you might not realize that it holds 8 AA batteries that you load into it. Your flash won't be any stronger (i.e. it'll still have a guide number of 58m), but it'll recycle faster, about double if CFn12=1, about triple if CFn12=0. I use the CP-E4s whenever I can, for one of two reasons: to visit the flash less often to change batteries, and/or to get faster recharge times.