The old rebel rolling chassis provided us with many of the needed parts - wheels, tires, brakes, etc... which was a real bonus - but it also supplied us with many rusty, broken, stripped or missing parts. In fact, most of our difficulties were because of the old parts, not because of the conversion itself. Without these annoyances, the conversion would have taken about two and a half days.
With an onboard 48V charger and 3-prong wall plug hardwired on, recharging is easy anywhere there's a wall outlet. Charging time depends upon how depleted the batteries are, but usually they were topped off after 5-8 hours.
Step 1: Gather Parts, Tools and Materials
BASIC PARTS LIST
Honda Rebel 250 rolling chassis
Perm PMG-132 electric motor
(4) 12V 50Ah batteries in series
36V-72V PWM controller
5 k potentiometer (i.e. twist grip throttle)
48V AC charger
48 -12V down converter OR additional small 12V battery (for lights, signal and horn)
#4 welding cable and lugs
4" angle grinder (with cutting and grinding wheels)
Metal band saw
Standard auto shop tools, wrenches
Heavy duty wire cutters / crimping tool
Honda Rebel service manual
Make Magazine Gear calculator (for choosing sprocket sizes)
EL Chopper ET builder's plans - outdated, but a great starting point
Friends who can help
Step 2: Stripping the Frame
Once everything is removed from the frame, clean it thoroughly. Be sure to remove all grease, dust, dirt. Lightly sand any rust spots.
Step 3: Removing the Motor Mounts
Using a combination of 4" angle grinder and Sawzall, remove the existing motor mounts points and tabs.
Step 4: Cutting the Swing Arm
This step requires precision - the motor must sit perfectly in-line with the rear wheel, so that the chain travels straight between them without any flex or twisting caused by misalignment. We used both a square and straight-edge to mark the cut lines with precision.
Step 5: Fabricating the Swing Arm Motor Mount
Two holes are measured and cut for mounting bolts, then the piece is welded to the swing arm and the motor attached.
Step 6: Battery Tray Fabrication
The original design for the battery trays used beefy 2" angle iron to insure that they could support the weight (about 50 lbs. each). This was not a great choice. It added far more weight then needed. A redesign of the bike uses slightly smaller batteries, which helped in several ways.
A newer re-design of the bike uses smaller batteries. Now all four batteries could fit into the engine compartment - eliminating the need for the two rear saddlebags. The new design also replaces the 2" steel with 1/2" angle iron as well as gigantic zip-ties. Overall, this new design saves a ton of weight, which helps to offset the smaller range of the smaller battery set.
Step 7: Painting the Frame and Parts
Mask off any bits of chrome and clean the metal once more. Use a rust inhibiting spray paint and coat the frame lightly with multiple coats of paint. Allow each coat to dry between applications.
Step 8: Gears, Sprockets
Once we knew the ideal sprocket sizes we purchased them online from Sprocket Specialists
Step 9: Assembly and AC Component Placement.
The new electronic components need to fit somewhere, including the motor controller, charger, fuses, etc... I found this old cooking pot and decided to fit the parts inside of it - It looked odd and dangerous, but somehow appealing.
Step 10: Wiring
One: Keep the old and new electrical systems separate, and run the old system off a small rechargable 12V battery. This option keeps the wiring simple, but requires maintenance of two separate battery/charging systems.
Two: Integrate the two systems by using a DC-to-DC converter, which steps down the power from 48V to 12V This is a more complex wiring set-up, but can be maintained with a single charging system, which is much more convenient on a day-to-day basis.
We chose to integrate the two systems together, so we relied on several sources of information to guide us, including the original Honda Rebel service manual, the suggested wiring diagram from the 21 Wheels plans, consultations with the guys at Electric Motorsport and quite a bit of guessing on our part.
It took a few tries, and we burned out some fuses and bulbs along the way. But ultimately we got the wiring working reliably.
Step 11: Conclusion - UPDATED!
However, the new batteries were small enough that all four could fit into the engine compartment - eliminating the two heavy rear saddle bags ( and all that weight). Using smaller gauge steel and gigantic zip-ties to build the new battrey trays saved even more weight. Sadly, the new design meant there was no room for the cooking pot that held the electronics, so those had to be remounted in an available spot.
The final design looks cleaner, weighs a lot less, but holds less power - a trade off that didn't result in much change in the speed or distance of the bike, which always fluctuated around 35-40 MPH, and 15-30 mile range per charge.
Visit Gomi Style for videos, plans and instructions for many cool projects.