I've been fishing with the 1600 one for 18 month and it lasts me great as most of the time I use the dim setting for baiting up etc and the full setting for wading and pulling fish in.
I saw the 3200 lumen ones and thougt I'd upgrade but on the first time out with it found the battery died due to the low setting being like the high setting on the 1600 lamp the battery just going off has put me off as if I was wading off somewhere the last thing you want is your lamp to die without warning.
Just wanted to give yous the benefit of my experience oh and the battery was fully charged.