It's a 3700 and the only time I ever tested the voltage cutoff on the Quark, which was set @ 3v per cell, was @ the track under race conditions and it went 10 minutes and 7 seconds geared 13/48 with a p.o.s. XLT4 motor. I would imagine it will probably go a minute or two longer with the Neu motor. I use 1800-2300mah in a five minute qualifier depending on track conditions(and who I'm racing with). As far a 9xl goes, I have no idea.