A few months back, I was doing just that. Running 36 volts through a Currie 450 watt 24 volt motor. It do indeed have some torque.

As you, I also noticed the extended battery duration. One of my problems was the added weight of the third battery. I still haven't worked anything out for mounting them lower. While riding the bike with the extra weight is no problemo, it's when I park the darned thang. I've already dropped the bike a few times cause I can't find a suitable kick stand.
If you remember, I was also having a problem with "stuttering". I couldn't go even half throttle from the git go without the whole thing going herky jerky on me. I had to get up to speed before being able to go WOT. Are you having any similar issues?
I've since backed down to 24 volts, but still have that stuttering issue. I know it's not the bike as it's happened on another ebike that was set up with a hub motor. Btw, running 36 volts through that 350 watt 24 volt hub motor would cause it to get hot. The Currie motor also ran just a tad warmer than usual.
This past week has been fairly dry, so I used the bike to get to work and back. I supposed I can live with the stuttering, but I need more gears. The motor pushes the bike faster than I can pedal, with the existing 7 speeds. This means I'm limited to going less than 20 mph. More like only 15.
I may have to forego the cool factor in using a cruiser frame and go with the original ezip frame so I can get more gearing. It's also more sturdy and can handle the extra weight of a third battery without falling over. Back and forth, back and forth.
