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?
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
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.