I wanted to confirm that I have used the 622Cs with Eneloop XX batteries, and they have fired now for around 700 shots (all of them with flashes, mostly ETTL) spanning 6 days (and with the eneloop pre-charge from factory) without requiring recharge.
I'm going to recharge the batteries just in case, just so I don't need to change them in the middle of a session tomorrow, but the battery response is very good, IMHO.
Maybe someone can confirm how much time / pictures spanned from full charge to depletion so I don't charge my batteries ahead of time. Thanks,
Based on those measurements from our Italian Ambassador, it's more the time they are on rather than how many shots. Based on his numbers, my estimate for 2000mAh rechargeable (as well as standard battery) is around 50 hours.
Of course, any sane person will take (max) half of that, and recharge the batteries after 25h as you don't want them to die on you.