I was in search of my first ebike conversion kit. After much searching for a complete electric bike conversion kit, I decided to take a chance on eBay DIY since the offers there were more than $300 cheaper for comparable kits from any dealer. The bike that I converted is a Jamis Explorer 2. It has front suspension and the riding position is more upright than your typical mountain bike. After much internal debate I settled with the following combination, a â€œ36V 15AH LIFEPO4 Lithium Battery electric bicycle bikeâ€ from daoji666 and a â€œ36V 500W ELECTRIC BICYCLE ENGINE REAR CONVERSION KITâ€ from yescomusa. This conversion kit advertises approximately 18mph or 30kph. With the battery choice I made I am hoping to get approximately 20 miles on a full charge. Although I would like to go a little faster, from what I have gleaned on the forums and from testimonials, as speed increases the range decreases on a disproportional decline. I also read that the life span of the battery pack increases when you do not completely discharge the pack. Since I work approximately 6.5 miles from my house and wanted to make a complete trip with out having to charge at work and I am 6â€™3 and 250lbs, I also figured that these were not the variables used in the manufacturerâ€™s equations for determining range or speed. They probably use more liberal figures that help their final numbers.
First about the kit, it is a complete setup. It includes, grips, rack, battery bag, thumb throttle, brake levers with cut off switch, complete rear wheel and controller. The rear wheel is double walled aluminum with heavy duty spokes and comes with the tire mounted. The grips are shorter than the originals and look fairly cheap but they still function well. As I already had a Topeak QuickTrack mtx luggage rack, I had no intention of using their rack or bag which are not of the highest grade and heavy but adequate. This might translate to sturdy but I wonâ€™t be testing to find out. The brake levers are fine except for the fact that my brake levers and shifters are one piece and canâ€™t be replaced. Integrating the cut off switch into my existing levers is also not possible. I could rig a magnetic switch on the frame next to the brake cable but I decided to leave the cut off switch out of the equation as the thumb throttle is easy to release before applying the brake. I am an avid motorcyclist and have many years, over 25 but donâ€™t tell anyone, with powered cycles. Without dissecting the controller I canâ€™t speak to its build quality except for it appears to be constructed out of aluminum and the screw on end caps were bent a little. The wires exiting the case had been encased silicone to prevent moisture from entering, a nice touch, but there in no apparent grommet for fray resistance. I hope this does not become a problem. I did have an issue later, so see the testing section for details.
It was the proverbial kid at Christmas scenario while waiting for the components to arrive. The kit from yescomusa came in about a week as advertised while the battery took the slow boat from China and arrived in approximately 3 weeks also as advertised. Installing the wheel and electronics was not particularly difficult. The hardest portion was deciding where to mount the controller. I knew that it needs air for cooling as in Maryland where I ride it gets around mid 90â€™s to 100 in the summer. I settled on the frame beneath the seat post facing forward, for the controller, just below the top frame. Since I received the kit first, I decided to put it together ahead of the battery. It took me approximately three hours from unboxing the components. Some of that was head scratching trying to understand which of the components I was going to use. The first problem was that the electric hub was a five gear cassette and my rear derailleur was set up for a 7 gear cassette. The second problem was the thumb throttle travel interfered with my shifter. A bit of creative positioning and some wire ties fixed it. The axle was a very tight fit, but it went on without too much of a problem. The after securing the rigging and checking for smooth operation of the brakes and derailleur off we go for a quick non powered ride. I was surprised that I did not notice any significant drag without being under power until I hit approximately 18 mph at which point it became much more apparent but still an acceptable ride.
The battery is quite a brick and fits my luggage rack well. Both the battery and BMS came encased in duct tape, you have to be impressed with that, and has an attached battery management system. There is no specification sheet that comes with the battery or BMS so itâ€™s specifications have to guessed at. The supplied charger states that it is a Lead acid charger which gave me cause for concern, however, after much research it appears that lifepo4 can be charged with the supplied charger. When I tested the charger the output voltage was 46v. I concerned as I have many LiPo packs which are extremely delicate. During the first charge I closely monitored the process and it cut off automatically at 42.5v. I will have to assume this is the battery management system at work. I disconnect the charger and let battery management system do its thing for a while and it balanced the pack to 40.5v. Then rinsed and repeated until maximum charge was achieved. All appeared to be well. The instructions, which are very poorly written, suggest that you do not leave the charger connected for longer than 9 hours. This has to be a good idea. After connecting the battery to the bicycle and going for a very short ride, it chose to rain for the next three days of course, I was quite impressed. The speed was exactly as advertised, some where between 15.5 and 18.5mph with no peddling and 18.5 and 21mph with light peddling. I have a steep hill to climb in my neighborhood, which it powered up with only light peddling from me in top gear and I was still doing 14mph at the top. After the rain finally stopped I went for a real test run. I planned a 15 mile round trip and left with a smile on my face. After stopping at some friends houses to show off a little, I ran into my first problem. The fuse included in the motor kit had jarred loose from bouncing around and the power kept cutting off. The fuse was developing a char from being loose, so I took it out of the loop and replaced with a better fuse holder. On the next leg the power cut off again and I found a cold solder joint on the battery connecting plug as well, time to re-solder. At least the peddling with out power is still just fine.
All in all I could not be happier. I recommend going over all the solder joints prior to first run and replacing the fuse and holder with a higher quality set. With that being said, I have approximately 45 miles on the setup and my commute to work is so nice. I used to have to change my cloths as I would get extremely sweaty. Now the ride is just a pleasure as I cruise past the backed up traffic. The bicycle is just so quite and smooth. I have estimated at the range at 21.66 miles with me peddling lightly most of the time. After 6.5 miles it takes just under 1.5 hours to full charge. This is a 3amp charger and a 15 amp/hr battery, so I estimate at 21.66 miles on the low end. I definitely recommend this for a commuter but not for a speed junkie.