Do not use the packs with AA's, trust me, you'll go nuts from all the charging, unless you have a 15 min charger that accepts 12 batterie. at a time... i've used those cpe3 packs for two flashes and that's 24batteries you need to charge every time you want to use them.
I bought the GoDox pb520 or something like that, build in battery you can just plug into to the mains and charge it, lighter and I get at least 400 shots at near full power. They are really great and not that expensive. Set the recycle function on your flash to only use external power to recycle, that way your in flash AA's lasts way longer...
