Dual Motor

The only info I can offer you is from an unlikely source. When you are told that the two motors would have to be somehow synced up so they don't overheat, remember that Popular Mechanics or some such mag worried about the same thing when they built a Honda Civic Wagon with an engine and automatic transaxle at both ends. The answer came to them when they tested it: The road itself keeps the motors in sync. I'd suggest you try for two hub motors of similar power, though, or at least similar running speeds (with the weaker one on the front wheel), and keep in mind that you'll need LiPO batteries to get the full benefit from that configuration...

You know I was thinking of running a Currie electrodrive motor attached to a hub motor. I figured it would create a good amount of torque for climbing. I tried to attach a left side freewheel gear onto the disk break threads on the left side of the hub motor but the threads didn't line up. Oddly enough, a standard one speed freewheel will attach to the disk break mount just not the left side kind for a flip flop hub. I don't know if this helps but maybe it'll "spark" some ideas.

http://www.hightekbikes.com/dual-motor.html

Hey- I was looking at doing a similar thing, two wheels on a bike with 26 inch wheels. I had a couple of questions and any input would be helpful and much appreciated. First of all, I was looking at the 48v 1000w motors that I've seen for sale (http://www.thelashop.com/electric-bicycle-motor/) and was wondering if anyone had any experience with them. Also, I was wondering about batteries and what people would recommend. The point of this would be to use as a commuter for the 14 mile run to work. I was wondering if two smaller batteries might work better than one larger one? I've been looking mostly into Li-polymers, but am open to suggestions.

I guess the ultimate question is would the two motors increase the top speed and if so by a worthwhile amount? Or would they just increase the torque for hill climbing? Also, assuming that I can charge the batteries at work, what would be peoples recommendations for how large a battery I would need (for one or two battery set up)

Thanks!

Rob

I bought a kit from thelashop but it was the 36V 800Watt kit. The wheel has a lot of power, so much so that my battery drains in about ten miles. I believe that two motors would increase your range and torque. Also you need to figure in your weight and the terrain. How much pedaling do you plan on doing? The more you pedal with your motor the greater your range. One problem I have is that I weigh 330 plus Lbs. Stay away from lead acid batteries they weigh too much. I don't think two motors will increase the speed. I think that you'll just get up to the top speed faster. Also if the front fork on your bike is aluminum, the motor could break your fork. You might have to look into getting a steel fork. A steel fork may weigh a little more but with two motors it's not really going to make a big difference. Also you should look into getting torque arms. I got mine from Ebikeit. You should check out this site for batteries bmsbattery.com. I hope this helps.

Thanks for the info!

How large is your battery? This also might be a silly question but I was thinking about using a cruiser frame, and a springer fork. How fast does your 800W get up to? I plan to pedal the whole time but was hoping to be able to move pretty quick, the 1000W say they can do 50km/h and I figured with two and me pedaling that I might be able to do even better.

The battery is a 36V 10Ah and the motor gets up to about 25mph. With motors that powerful in order to pedal along with them at top speed, you'll need a large set of chainrings and a pretty small set of rear gears to achieve the correct gear ratio. The cruiser frame is a good idea because it should be a lot more durable.

I've seen a few postings about dual motors, one thing to consider is making sure your battery can handle the high discharge rate or you will cook the batteries. Should be a heck of a ride though.

Hi

Im thinking if a motor is rated at 50km/h the speed limiting factror will be the rated motor RPM(or battery voltage). It will never go faster than 50km/h even if you use 27 motors you'll just get to top speed faster. If I was you I would get motors with a higher gear ratio for 26' wheels. It wont be that hard because they make the gear ratios for differant wheel sizes anyway. So if you get motors rated for 50km/h in a 20' wheel and you put it in a 26' wheel it will go much faster but it will take longer to get to top speed. You combat this by massive horspower. Above 60 a bicycle gets very scary so if I was you I would look for a motor/wheel ratio combination to get to about 75km/h and 2000w should be plenty power to get you there.

Im only talking about motor RPM and assuming that the controler and Battery voltage and power is correctly sized for whatever motors you use.

Anyway it should be a monster.

Check out this a 48 volt, 15 horsepower board track racer - http://www.instructables.com/id/48V-Electric-Flat-Tracker/

Another thought is, check local, state, federal laws for the level bike you plan to build. A bike, moped, scooter, or motorcycle is going to have very specific legal requirements to get on the street. Last thing you want to do is get an awesome machine together just to find out its not legal on the streets.

Another place with some pretty wild builds is http://www.falconev.com I'm not affliated with them in any way, and found em from posts here on the forum.