A couple of weeks ago, I stumbled across a web site for electric bicycle systems. They sell Wilderness Energy products, and they had a 50 percent off sale on some of their hub motor kits. Their name is WerElectrified.

I don’t have a whole lot of money, but I recognized a bargain when I saw one, and bought their 24 volt, brushed system, the cheapest they had. After shipping and taxes, it was about $190, and would have been $150 more than that normally. Just 2 days later the sale ended and the prices went back up to about $300.

It was shipped by UPS ground, and got here in less than a week. I eagerly hooked it all up for the first time, and it did not work. I then discovered that the wiring for the controller was reversed on the battery side, and the wiring harness had been set up that way at the factory. Oops!. So I pulled out my soldering iron and heat shrink tubing and fixed it. It still didn’t work, probably because it was blown up the first time. There was no fuse in this system, and my first mistake was not to add one before I hooked it all up.

I decided that the controller must be toast, and pulled out a drawing for one I built for another bike a long time ago.

I have a lot of experience designing and building high powered electronic systems, so I am able to build a new controller from parts I can get locally, at places like Fry’s and   HFE Electronics.

The other bike I just mentioned was one I had in San Jose, around the year 1994, I think. It had a double Zap motor, in series, and 3 12 volt batteries, and the controller was set up for 20 amps. Total electric power was about 700 watts. It needed all of that because it was a conventional bike, not a recumbent, and it was a friction drive, not a hub motor. I used to commute to work with it, and if I ran it full power, and pedaled too, I could pass up the bike Nazis with their $2,000 bikes that don’t have kickstands and their black, Lycra underwear. That was fun.

So I went ahead and built my own controller. It’s a box mounted on the handle bar, with some kludgey looking wiring going to the motor and the batteries, featuring bag ties and unclipped tie wraps, at least until I am sure everything is where I want it to be. Right now it looks really homeless, but it works.

The business end of all of this is a 250 watt hub motor on the front wheel, and more homeless looking wire ties, and brakes that still need more adjusting because the rim was a little wider than the original one. Also, I noticed that the wheel needs to be trued. The spokes are a little longer on one side than the other, so it goes up and down a little as it turns.

There is still a lot of work that needs to be done, but I took it for a test ride today because I heard that the weather was going to be really wet and nasty for the next few days, so I won’t have a chance to try this for a long time if I don’t do it now.

I rode to the Co-op and got my morning java, as well as a few normal shopping items. That’s what the basket on the back is for. I do this a lot. I like the Co-op and usually like the ride there as well. The ride went really well, no problems, and the batteries held up all the way there and back. Much better than expected with my untested controller and really ugly wiring job.

The unusual bike, as well as the electric motor attracted some attention, so I chewed the rag with some people about recumbent bikes, and about this motor experiment as well. I often end up doing that anyway, just because many people have questions about recumbents. I have always liked “bents”, as they are called, because they need less energy to pedal, and they are very comfortable.

I have a lot more work to do to finish this project. The kit came with a very good rear carrier rack, which I will install to help carry the weight of the batteries. On a “bent”, it needs to be modified a little bit in order to work. I need to clean up the wiring, and I would like to add panniers and a third battery. The small wheel needs to turn faster to get any speed. It was about 11 MPH when I was riding with this setup. This motor usually goes on a bigger wheel, and rolls faster at the same RPM. Most DC motors can run at 50 to 100 percent more RPM without wearing out much faster than normal. This is not true of shunt would motors, because the field coil will overheat, but you can do it with permanent magnet and series wound motors. They actually become a little more efficient than usual.

There are a few other things that need to be done, but I am very pleased with how it came out. This will make this bike even more fun to ride, and I have always enjoyed it anyway.

11-9-09 Wiring is complete, and everything still works OK. The motor has a top speed of a blazing 11 MPH on level ground, and enough torque to climb a moderate incline at 1 or 2 MPH less speed, but needs help if the hill is very steep. I found that it can pull my cheap, thrift store trailer at 9 or 10 MPH, This trailer has small, hand cart style wheels on it to replace the more expensive, but far less durable original wheels. They were plastic, and the rims tended to split if the tires were inflated to more than half their rated pressure, and replacements cost $40. Ouch. The hand cart wheels last much longer, and are cheaper, but have more drag. If I had more money, I would get a better trailer, with real metal rim wheels, made to last as long as the ones on the bike.

Anyway, it works, and I can haul a full water bottle home from the co-op with it. The speed could be increased to about 16 MPH by adding a third battery, as I mentioned before, but it would cost money for the battery and the 36 volt charger. I don’t plan to do that for a while, if ever. A healthy person could pedal faster than it goes now, easily, but I am not into speed.(Guess I am still a turtle, oh well.)

By the way, the controller has a variable current limit, something I have not seen anyone else do. This is why it has 2 control knobs on it. The bottom one is the current. You can turn down the amps, and torque, if you want to both pedal and use the motor. You can get just as much exercise as you want doing this, and increase the range, as well, or max it and just use the motor. It’s a good idea and I am surprised commercial controllers don’t have this. Even at full current, the brakes easily stop the bike, and then you can just turn it off until you are ready to go again. If the rotor is locked, it will still pull an amp or two from the battery, so it should be turned off when not moving. No matter what, I have never seen the motor get much warmer than the frame of the bike. Very efficient.

It’s my understanding that you can have as much as 750 watts and 20 MPH on an electric bike in California. That’s ironic when you realize that an athlete on a racing bike can go much faster, but that’s the way it is. Many other states are even more restrictive. Governments in the United States seem to have a problem with electric powered vehicles of any kind, and I would guess there is a connection between that and the big handouts the politicians get from the oil lobbyists.

Enough of that. I’m just glad I stumbled across the sale at WerElectrified, and had a chance to try this. It’s fun, and I will probably be doing even more bike riding now.

By the way....

Here is the original controller. Notice that it has weird symbols all over it, not unlike those found on the beams and internal structures of the UFO that crashed in Roswell. Could it be that this controller was built by the grey aliens, the same ones who built all those UFOs that crash all over the place. That would explain a lot .   ; )

(See the next entry for more info about the bike motor)