Which batteries to get for an external flash?

[Mary Anne]

I have been using Enelope rechargeable batteries for years AA in my Canon Twinlite, Canon speedlite, Olympus Flash all used often for shooting Macro.
They also power our very old Uniden Cordless phone, and two clocks..
AAA in Remotes six of them could be more, they power kitchen scales, bathroom scales and head lamps.
I have two Battery chargers a Enelope Super fast one about 1½ hours ? and a slower Energizer one 5 hours.
I use the slower one most of the time, as I have plenty of spares and I read somewhere that charging them slower they last longer
Don't know if its true though I have not had to throw any away in the years I have been using them.
I bought the first 2 packets of Enelope Panasonic made batteries last year, for my Olympus Flash they dont seem any different to the Sanyo ones.
They get the from me too.