I get about a 7 minute timed and logged run (micro logger) with IB 4200's using a 41mm prop. IB4200's are very bad for self discharging. After about 2 days at rest I lose 1000mah from them. Always re peak them before going out for your first run. Batteries run well when warm and freshly peaked.

Off the charger a six cell pack should be nearly 9 volts.

I currently have a "dead cell." It will charge to 5000mah without any heat, they only feel warm to the touch after I stop them at 5000. The cell will only discharge 4000mah from it at 3A to 0.9v. The problem is after 2 days voltage drops to -0.05v, yes negative while the other 5 cells still show 1.30 -1.35v per cell. I'll probably end up buying another sport pack of IB4200's just to steal one cell, as I can't find single loose cells anywhere.

I own 7 six cell packs and perform more maintenance on these then on all of my nitro boats.

Ryan