Ben‘s Electric Motorcycle (B.E.M)
Update 8/12
Rode the bike to work today despite battery pack issues. I purchased a 72V LifePo pack from Elite power solutions. It comes with sensors for each cell and a computer that displays temp, voltage, capacity. It should have been a great upgrade. However, I had to make a new battery housing from scratch and I’m not the best welder so that took a long time.
Then after I got that done and hooked everything up. I blew up the computer right in my face. It was quite scary, but I didn’t get hurt so it just cost me a new CPU.
I have added an emergency shut off that I should have had from the beginning but I thought my key shut off was enough. I found out that I was wrong when I blew the CPU up again, the exact same way. Fortunetly I was able to put pieces from the first CPU into the second and get it working again. One set of sensors is not working so the CPU does not correctly show the pack capacity or the status of all of the cells.
I’m not going to take any long rides since I don’t know how much juice I have, but I can get to work and back so I’m good for now.
The BEM is for sale if anyone is interested $5500. It’s just basically the cost of the parts.
Update 8/8/09
Finally broke down and bought 4 new optima’s. However, I left the new batteries I got before in the bike and they got drained. One of them I was able to get charged up but the other is toast.
I now have 7 worthless batteries, if anyone knows how to save them or where to recycle let me know.
UPDATE 8/08 – I bought 2 new batteries in hopes of riding again but the others were worse than I expected. I need 4 more new batteries but at least Optima has a rebate going on now.
UPDATE 4/08 – Two of my batteries don’t hold 12Volts anymore and they are bringing down the whole system. They will need to be replaced to get my range back. I’m in the process of finding Lithium Polymer pack so well have to see how that goes.
For questions and other comments check out my instructable with over 200,000 views.
Introduction
I only work 3 miles from home so an electric vehicle seemed like a great idea. I thought a motorcycle would make for a good first EV keeping costs down and more fun to ride.
This project took about 3 months of actual work, not counting waiting for parts to come in or help from a friend with the welding. Take a look at the Construction page for photos and details.
All in all, it cost about $3000 to buy and build. This may never pay off in gas savings(unless prices keep going the way they are), but if you add the fun of building and all of the environmental benefits it was well worth my time. With a top speed of over 70 mph and 10 miles per charge this bike is perfect for me.
Decisions.
Every vehicle is different but I bought the El Chopper book to get a general idea of how this is supposed to work It was helpful but there is enough information on the internet if you don’t want to get it. See my links section for some of the helpful sites I used.
Frame . I looked at a LOT of different bike styles and decided on a 1984 Honda Interceptor for a few reasons. 1) I like the style of bike, not a total crotch rocket but not a hog either, with plenty of room for batteries. 2) The seller on Ebay was close to my house 3) Cost.
Motor . After reading other peoples bike specs and deciding that I wanted to go faster than a moped. I figured I needed a bigger motor than the popular 48Volt Etek. I found the 72V Advanced DC motor, the weight and dimensions where good for my frame so I ordered it online from thunderstruck-ev.com.
Batteries . I went with 6 Yellow Top Optima batteries because they are sealed and have gotten great reviews. After making cardboard mock ups of the D23 model I realized that 6 wouldn’t fit, so I ended up getting the D51 model. Half the size and weight but also half the storage.
Controller . You have to match your controller to your voltage but the amperage is up to your budget. More amps = more power and more cost. It seemed that there are only two standard choices Alltrax or Curtis, you’ll have to decide for yourself but I went with the 72V 450Amp Alltrax.
Don’t waste your time trying to build a potometer on an old throttle just buy a pre-made one and be done with it. I got the Magade Twist grip Throttle .5Kohm from cloudelectric.com
Charger . You have to match your charger with your voltage but the speed of charge in Amps is also up to your budget. I was going to get (2) Soneil 36V chargers and link them together to get my 72Volts but decided the extra money was worth only having one charger to worry about and get the faster charging rate. I went with a Zivan NG1 from EVAMERICA.
In fact they had a scratched model that gave me $50 off.
DC/DC Converter: It’s best to run with a DC/DC converter and an extra 12V battery but motorcycles have limited space so I am only using the converter. A Sevcon 72V Input 13.5V output from evparts.com.
Other Stuff: Some other items you will need for safety and construction.
Fuses – ANN 400 w/ holder. This was rated for my amperage.
Albright Contactors SW-200. This is a device that you can hook up to your ignition on 12Volts and it will close the loop so you get the full power to your controller. Very nice.
Battery cable and connectors- I just bought 10 feet of 2 GA from WAL-MART and cut them to length and some universal battery connectors.
Instruments – E-meter(Link 10) w/ Prescaler add on for 72V use. Instead of a bunch of different meters I just went with the e-meter from a boat store online. I kept the speedometer that was already there and hopefully can use the temp gauge for the motor.
Progress.
I got started by searching online for components and a bike with a suitable frame. I won a 1984 Honda Interceptor on ebay. After picking up the bike I began taking out the I.C.E. components and stripping it down. That was a little more messy than I thought but a little cat litter will get those oil stains out.
I hope. Thanks to my friend Russ for helping me get the motor out and working on the brakes. I made up mock cardboard components for everything to see how it was going to fit. It’s a lot easier to move 6 cardboard batteries around than it is to move 6- 46 pound lead ones.
After I got everything where it needed to be, which included cutting out the bottom of the gas tank and an old motor mount. I started cutting wires off the bike that I didn’t think I needed. and then I checked the manual. -)
I got it all wired up after a few days and a few beers with the help of other useful websites. Thanks again ev-america. I turned the key and zap! Large sparks and some smoke.
Oops I crossed a + and – battery cable. Good thing I put in that safety contactor. I fixed the wires and double checked all of my connections.
Turn the key, no smoke so I gave it a little throttle and the motor started spinning. I was pretty excited.
Some tinkering with the E-meter and I’m ready for the next step. I disassembled and took the bike to a metal shop for the battery and motor mount to be welded. I knew that I couldn’t do this part so I didn’t even pretend. My good friend Nick offered to do the welding.
He did an amazing job, my many thanks go out to him and I think I’ll be owing him one for quite some time.
The construction page shows the work that he did building and figuring out the motor mount and designing a battery casing that would allow the batteries to come out easily in the small area allowed. He even welded a little personalized vin number on the bottom. The motor mount and cover turned out better than I could have hoped for.
Thanks again Nick.
The day that I got it back from the shop I rewired the system and gave it a test. The wheel spins, more excitement.
If you have a fast internet connection check out this 14meg video of my first ride. First time out. It’s nothing special because I didn’t have everything bolted in but it proves that it works and it rides great!
I tweaked the speed controller, cleaned and lubed the chain, tighten all my bolts and connections and now I can see how far and how fast The BEM will go.
Final specs are in I have gotten over 70 mph and start up with traffic no problem. The distance seems to be what I expected with the smaller batteries. I can go 10 miles at 45mph before it needs to be charged.
I may change my battery’s or get a different sprocket to see what that does, but I’m pleased so far.
Component/cost breakdown
Frame . 1984 Honda Interceptor 700 $600 from ebay
Batteries . 6 Optima D51 12V 41Amp 26Lbs $643.80 from remybattery.com
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