Quick question, I didn't get a manual with my cp-e3 battery booster pack (ebay). Should I load the flash with AA as well as the 8 that go in the pack, or just the pack? Does it bypass the ones in the flash?

Thanks in advance

Batteries in the pack will power the flash output, bateries in the flash will power the menu, lcd, etc.

So yes, you need batteries in the flash too when using a pack.

With some flash, including the 580EX, you can set a custom function so that power for recycling the flash (i.e. recharging its flash capacitor) comes from either the external source only, or from both the external source and the internal batteries. I usually set it to external only, so I don't have to swap out both the internal batteries and the CP-E3 batteries. I use the CPM-E3 reload tray, so it's very fast to get a reload.

I see, thank you for the replies! I have a 550EX and a 580EX, I'll have to see which to use. So if I use the function on the 580 to use both sets at the same time the recycle should times would be the fastest at the cost of having to replace 12 AAs at one time?

stevez32 wrote:
I see, thank you for the replies! I have a 550EX and a 580EX, I'll have to see which to use. So if I use the function on the 580 to use both sets at the same time the recycle should times would be the fastest at the cost of having to replace 12 AAs at one time?

Yes. Faster recycling time and the whole show lasts longer. I get around 1500 frames out of the 12 batteries in normal use. I tried shooting with the pack firing the flash and the Speedlight AAs looking after functions but went back to all AAs doing the work for the above reason.

I use Sanyo Enelops and they're great, I have spare trays for my packs and simply slap them in when I notice power drop off same as jcolwell.


The CPE4 is noticeably faster (if you come across one) and the tabs that hold the AAs in place are a lot stronger on the 4 vs the 3. I've broken all my tabs on 2 trays I use with the 3 and the 4 is fine.

Cheers Gaz