try testing at home gordon, my v3 lights used to come on after 3-4 hrs, which was extremely early IMO, and afetr is ent it back to get modded, it hasnt come on once, i KNOW the v3 w/ my mics/bp-50, can easily get about 9 HRS so...... 3 hrs into recording is early, prolly just needs calibrated, doubt its the batts
i ahve a few IFFY bp-50's, and they get warm and all when they charge, but the still power the v3 for about 9 HRS

YMMV