my electric bike conversion
I just finished my electric bike conversion and thought some folks might be interested in seeing it. here is the link
The hub motor is from EV tech and is surprisingly powerful for its size, especially when run at 48 volts.
I am running a LiFepo4 pack from YESA, 48/12
The combination of high torque and the nearly silent free wheeling motor make the bike a lot of fun.
Nice set up. I also electrified a folder, but mine no longer folds due to battery attachment on the frame. I just do not like the weight of both motor and battery on the back wheel. I got a pinch flat once with that configuration when I hit a pot hole. I too have trouble pedaling with the motor. My set up with a HS500W Bionx motor cruises at 26 mph on the flats, no pedaling. I am looking into replacing the 53T front crank and install a Schlumpf high speed drive on the front bottom bracket so I can pedal along with the motor at full power. You can see pictures of my set up by clicking on to my name and clicking on to my blog if your are interested.
That thing must really move. My 900 watt scooter has a 20 amp @ 36v continuous limit, and doesn't do too bad on the hills with its chinese brush motor & chain drive that I'm sure is not nearly as efficient as the BMC brushless you have. The top speed is about 20 mph, and with a moderate to mild hill profile ride the avg speed turns out to be about 16 mph average.
What's your average speed on an average ride?
I am surprised you can get that kind of unassisted speed on a 20 inch wheel mounted hub motor. Even the monster Crystalite Phoenix kit only shows the mid 20's when running 20 inch wheels. Did you modify something?
I haven't done a long trip on the bike yet with normal terrain. One 15 mile excursion with a ton of hills and some dirt riding got me about 16 MPH average speed. that same course unassisted, I would have been below 10.
I put the heaviest duty tubes I could find on the bike-they are about 3X the thickness of a normal tube. Probably could ride on the them without a tire! A flat of the rear is a real pain to deal with with the hub motor and wiring to deal with.
The hill climbing ability of that BMC hub and the 20 inch wheel combo really is something. I love going 18 MPH up hills in my second tallest gear where I'd be going 6 or 7 in a granny gear normally.
I just read about the new Bionx 500 watt motor, as I was not familiar with their newest offering. Seems like they have it geared taller for top speed and actually call it a high speed motor. The article I read said the 350 watt Bionx motor actually had more torque for hill climbing. Gearlon cycles has front crank rings up to 60 teeth if you wanted to be able to pedal at those speeds.
Finally got a chance to try the bike out on a normal street ride (normal for the East Bay of the SF region that is) I rode about 10.5 miles, including some long 10 to 15% grade hills. The best average time I ever got on my 19 pound rode bike on this ride was 12.8 MPH. The electric bike with 2.35 Inch knobby tires with only 40 pounds of air in them did the same route at 19.6 MPH! I was in my tallest 3 gears for the entire ride, and went up the steepest longest hill at nearly 3X my normal speed. A lot of fun, and I still got a workout. Its amazing how fast you can actually get somewhere on a good electric bike. the YESA 48V 12AH LiFePO4 pack still reads 52 volts at the end of the ride. I still need to do a how long can I go ride to find out the limits of the 14 pound battery pack. I'd guess 20 to 30 miles depending on how much I help, and how many hills I climb.
S. Calif does not have nearly as many steep hills as SF but the Palos Verdes peninsula is pretty close. I run slick road tires but I lowered them to 45psi due to the weight of the bike and the spare battery I carry in a back pack, total weight about 46 lbs. I rode the entire peninsula and picked 2 of the steepest 10% grade hills. Total trip was 36.5 miles, averaged 19.4 mph in about 1 hr 56 minutes. I was going down some of the hills at over 33 mph. I nearly used up both 36V Li-Mn 9.6 hr batteries. I was passing a lot of road bikes during the entire trip. The only time they are able to pass me is downhill, they must have been going 45 mph plus down some of the steeper sections. But as soon as the road leveled or when they hit a slight incline, I would pass and leave them behind. Your higher voltage set up is the way to go, it seems higher voltage is more efficient at high speeds. Too bad Bionx does not offer a 48V battery and controller upgrade with their closed system. Yes, the hub motor is the new high speed 500W motor. I purchased it from Electric Cyclery in Laguna Beach. Bionx does not make a 20" HS500W kit so I had to respoke the wheel.
I agree, it's alot of fun along with a good workout at 3x the speed, 4x in my case, my pedal bike is a mountain bike. That is why I can't understand why most bicycle shops still have not caught on. Oh well, that is their loss.
Oh, I was pedaling like a mad man to try to add power at full throttle and down hills.
A front crank ring with 60T will not fit on the limited space at the bottom bracket of the Dahon Mu SL but the Schlumpf high speed drive will. It is a 2 speed push button planetary geared crank, a 52T crank ring at low gear would give me the range I have now but when switched to high gear(2.5x), it is in effect a 130T high gear!
Installed Schlumpf high speed drive and tested. I can now sustain speeds of 27mph and maintain short burst of 30 to 31 mph on the flats. On a steep downhill, I was able to achieve a maximum speed of 43mph, while pedaling at high gear under full throttle. No more spinning pedals like a crazed monkey to try to add pedal power at high speeds.
Maybe a fairing can let me achieve higher speeds and better efficiency above 25mph.
thanks andys this is very interesting, I have been thinking of switching out my heinzmann for one of these too, on a 26" wheel. It reads from your post like the freewheeling is definitely close to zero and the sound level is low. please post further info/feedback whenever you can
I got 46v nimh already how much did ev tech knock off the price without the controller?
Do you have a meter so as to share more detailed info, ie what your readings are at different speeds/loads etc, i would like to compare them with my heinzmann brush motor. how many amps pulling at the 20 to 25mph range, steep hills what is happening, your peak amps, peak watts etc. you have ample torque for the steepest hills
I don't have a meter on the bike yet. Doug told me his motor is the most efficient he has tested-way better than the Crystalite hubs he also sells. He said even with his 250 pounds on a 26 inch wheel bike, the amp draw seldom goes over 15 even up hills.
I can detect no drag whatsoever on the hub motor when coasting. it is nearly silent, and usually the tires are making more noise than the motor.
He supplied the 48 Volt controller at his cost to me, and only subtracted $100 or less or so for the stock controller because he gets them as a kit.
The torque this motor has is amazing, especially with 20 inch wheels.
the motor sounds great, pricey but worth it. what is the dimensions of the 48v controller? also is it a 25amp? Does it have a low voltage cutoff? I don't see it on the evtech site.
Scroll down to the 48 Volt 20 Amp Roadrunner controller. Its average size for a brushless controller. You can also run the 48V 40 AMP Phoenix controller, but I thought that was overkill, and also my Lithium pack can't supply that kind of continuous power anyway.
and yes, it does have a low voltage cut off.