24 to 48 volt


New Member
I purchased a 24 volt EVG ebike nine years ago. Top speed 13 mph. If you pedaled above 14, the motor would shut off. The motor was nice for hills. Bike weighed 86 pounds per my scale. Frame is heavy but sturdy.

Anyway, after 7000 miles, the brushes were shot and I could not find replacements. I bought a not working bike (needed new batteries and key for throttle) for parts. At 10000 miles, I was on the second motor, fourth charger and blew the third controller. I gave it too much throttle at a low speed starting a hill. I probably could have replaced a few mosfets, but decided to upgrade to 48 volt.

I bought a Crystalyte (Phoenix Brute) kit as they have been around for a while. I wired two extra 12 batteries on the rear rack and am using two 24 volt chargers. The horn and headlight are operable from one 24 battery pack. I need to wire up the rear tail light. Bike now weighs 108 pounds plus my 190 for about 300 total. Top speed on level, no wind is 30.5 using a bike speedometer, 31.5 using the Phoenix speedometer. I am guessing range at 17/18 mph would be 20+ miles without pedaling. I usually do not let the batteries go below 50%. I now have 2100 miles on the 48 volt set up.

If anyone is interested in upgrading, I can email my wiring and answer any questions.
Sorry for the delay, life gets in the way of fun.

It's really not that difficult if you are can work a soldering gun. I am assuming you have a 24 volt model as I do. If you have the 36 volt model, I would just upgrade to a more powerful 36 volt motor, perhaps adding an additional 36 volt setup on the rear rack. Use 10 gauge braided copper wire. Solder all connections except to the battery. Save all unused parts. Use a volt meter to check everything before you plug it together. Warranties do not cover reversing polarities. I double taped all connections. It would be better to use shrink insulation.

I chose a 48 volt Phoenix Brute (torque). Phoenix has been around for a while and seem to be very reliable although heavy. 31 mph is fast enough and we have some steep hills around here.

Remove the on board battery pack. Remove the cover and replace the crossover wire containing the fuse with a wire. The fuse will need to be 50 amp. I located it in the rear rack bag for easy access, although it has never blown (yet). Clip the wire to disable the capacitor. I had trouble charging with it. Take off the right side plastic body panel. Remove the plug on the controller that goes to the throttle/on off switch. Leave the old controller in place as it allows you to have headlight/tail light/brake light/horn functions. Find the two power wires that come from the battery block to the old controller. Do not cut these, but remove an inch of insulation from each at different points so they would not touch if they came untaped. Solder a wire to each and run it to the rear bag area. Using black and red wires helps with + and - .

One wire goes to the controller. The other wire goes to the keyswitch if you are using one, then to one of the new batteries. I put the 50 amp fuse between the two new batteries, connecting them. Another wire goes from the last battery tab to the controller.

If you follow the current path, it starts at the controller, goes through the two batteries in the old case, through the keyswitch, through one of the new batteries, through the fuse, through the second new battery and back to the controller.

For charging, I am using two 24 volt circuits that may sound complicated, but it is not. If you flip the keyswitch, you now have two separate 24 volt circuits. I use the old charger on the battery box for the original batteries. Solder a wire from the charging plug onto the + side wire of one battery and the - side wire of the other. I use a 2 amp Soleil charger for the two new batteries in the rear bag/rack. I used several layer of cardboard to cushion the batteries and affixed a sheet of rubber (old inner tube) and cardboard sheet over the batteries to avoid short circuiting. The controller fits on top of the batteries. The lights and horn run off the front battery. You don't have to worry about them becoming unbalanced as each is 24 volt system is charged separately. Just turn the keyswitch off and plug in both chargers. Switch out the rear wheel, throttle, electronic readout and route the wires. And for heaven's sake USE A TORQUE ARM!!!

Other than the wires coming out from under the seat and going to the rear bag, it looks like a stock EVG bike. I carry a copy of an advertisement stating 400 watts with a picture and a copy of the state E bike laws.in case I am ever stopped. In 12,000 miles (2200 since 48v) that has never happened. I now have 1920 watts peak, 1440 constant.

It took me about 4 hours to do the upgrade.