The BTIs are solid. I was doing an endurance test with them and got bored at 75 minutes for one of them and 60 minutes for the other, and when I came back at about the 2-hour mark they were both done, so I guess an hour and a half on a PB180 with the backlight set to maximum but not a lot of HD spinning. These were used batteries, too, so I would guess better than than new.

Best,

John