I wanted to try the 60 volt mod on my wife's XB-600 but realized that I'd need a 12 volt 20 amp battery to match the others. Then I realized that I had four new 12 volt 10 amps sitting right here for my Vego. So I simply wired two of them in parallel to get 12 volts 20 amps, then wired THAT assembly in series into the rest of the pack.
It works REALLY REALLY well. With the shunt mod, suddenly riding this thing is a whole new proposition; I can often ride IN TRAFFIC rather than over at the side. I won't give numbers as I don't trust the speedometer at this voltage and I haven't downloaded my GPS logs to see how fast it really goes, but it now ZOOMS up hills it could barely take at all before.
I have ridden it a total of probably thirty miles since going 60 volts. No problem at all. The motor is a little warmer than usual but not much.
I can't emphasize how much this alteration changes the whole character of the machine. Suddenly it's one powerful little puppy!
Ironically, it has made me decide NOT to get one for myself, and NOT to let my wife ride it like this. It's almost TOO MUCH speed for these little wheels. After going as fast as I could for a couple of days and arriving white-knuckled I realized that I didn't need to USE all this speed all the time!
If you're considering doing the 60v mod, do it. And my method of using two 10 amp batteries seems to work great, YMMV, don't send me your repair bills!
Did you do anything to the controller other than the shunt mod?
I think that stock controller is 48v but I've seen posts about it being able to handle more than that. Do you think this would work on the xb-700li?
The only modification I made was the shunt modification (using coat-hangar wire; pictures available in that thread). The controller handles it just fine and apparently so does the DC-DC converter, which I was a bit worried about.
When you turn the key on now, the battery meter SNAPS to full - and stays there! Two 6 mile round trips don't budge it.
No idea whether it would work on the 700li. The usual caveats about charge balancing etc. would certainly apply, I don't know how much of an issue it would be.