I have the 501B xm-l from DX. I just ran down a 2400 Trustfire flame battery. It ran for an hour and a half before it dimed and started slow blinking. From what I have read 510 is reasonable at the emitter and it puts at least 400 out the front.
I bought this charger in May of 2009 and it has worked without a hitch. I use it about twice a week when I am riding.06105 Digital Li-Ion 18650 Battery Charger