72v 37MPH xtreme xb 508!!!
My first upgrade was the 72 volt and Shunt mod on my controller, described on zerogas's great xb 600 thread here. Many thanks to all the contributors there! Turns out it's a pretty simple matter of replacing the mosfets and caps with 100 volt versions of the same parts. Then all that's left is to attach the wire that comes from the key switch to a 48 volt tap point from your battery pack, and not the 72 volt wire coming from your controller. richardb has put together a great website detailing his mods,
http://www.bergerweb.net - on his xb 500 including specifics on what size and gauge wire to use for the shunt mod, as well as a nice schematic. The result of those 2 mods increased my speed from 21mph to 28mph, and improved the hill climbing ability a lot! I then rode my XB every day to work for well over a year, even on 106-107 deg. days, and the performance was rock solid and the motor always only got slightly warm to the touch, never a problem. Other 72 volt mod riders here report the same performance. I recommend this mod to all XB owners. If you are not good with a soldering iron, I suggest you pick up a 72 volt controller ready
My second upgrade recently was picking up an 800 watt 48 volt motor with controller I found on Deputydaves' 700li thread that fits XB's nicely. I noticed the speed at 48 volts on this new one was about the same as my old 550 watt motor running at 72 volts, but the torque on this new one was much better! I couldn't WAIT to get this one up to 72 volts also!! So the upgrade parts finally arrived and this last weekend I put them in. Then went for a test spin and top speed is now 37MPH!! The torque taking off from the line and going
up hills is amazing! It momentarily pulls 33 amps accelerating or going up hills and drops down to 22 amps on a level road. I have attached pics showing the new motor (looks stock huh) and the 2 extra batteries in the seat compartment.
*Note on axle washers: In order to be able to use the correct amount of washers on the axle to be able to tighten the wheel on the forks without binding as I was having problems with, it turned out I needed about a 1/4 inch more space between the forks in order to do so. In asking around a friend loaned me his 10 ton hydraulic "puller" (it's more a spreader really) he uses for car body repair to spread the forks. Sounds big but its actually a small unit about 2 feet long and about 4 inches wide. But plenty strong to spread those steel forks!
Many thanks to the creator of V is for Voltage and all the participants sharing tips here! I am no electronics expert, but there are many on here helping those of us out who are electronically challenged. Take a bow, this success is yours as well!!
Great post! Thanks for the update and the pics.
Are you in Phoenix? (Where else does it get 106-107 degrees on a routine basis) I am in Phoenix and ride my 700li to work almost every day. I installed the Cheng Chin tires almost a year ago, and the ride improvement was impressive. After 16 months of riding and almost 3000 miles, my range seems to have dropped a bit, to 18 miles per charge. I am 6'2", 225, and often ride in 100+ degree weather, so the bike is working hard no doubt. But I am considering the voltage upgrade that you did. I would also like to upgrade my LIMN04 to LIFEPO4, which I believe will require a new charger. Anyway, thanks for the update!
This is a terrific thread...so full of useful information.
I plan on doing much the same thing.
Why the 48V + 24V?
Would it not be better to have two equal packs of 36V + 36V?