J.A.F.N.G.

Region
USA
.Just another new guy from lake havasu city utah...And of course i have a lot of questions.
I bought a schwinn (ya, i know,) 21 speed hybrid...almost brand new. bought a 1500 watt rear hub drive kit and a 52 volt 20 ahr battery. Been ridding it every day for the last two weeks. Seems to run properly. I guess 35/36 on flat is about right? What is i controlt that limits top speed? It limie will pull ok up to 35 mph and it stops pulling...Some kind of speed control limiter in the control unit or is the just the the best rpm it will run with the available voltage? 35 mph is ok but because i am building a small trailer to haul gas and water back to camp i need more power to get up a few small hills i was going to buy a motor for the front wheel. Do i need another one rated for 1500 w or will a 1000 watt with a to do wh to dots own separate 52 volt be enough to do what i want? will one twist throttle control 2 systems?
Thanx jn advance
mike
 

indianajo

Well-Known Member
Welcome to the site.
Direct drive motors perform best at speed. 35 mph is quite fast for any bicycle motor. The limit on a US sold kit is usually the amp limit of the controller. The cheap 1000-1500 w DD motors are typically sold with a 30 amp controller. Batteries have their own amp limit - typically 50.
Hauling is another question. DD motors lose a lot of torque at lower speeds. Two ways to match the torque to a heavier load are gear the motor down with internal gears, or buy a mid drive motor that both has internal gears and a variable speed sprocket set. In addition a DD motor lugging at low speeds wastes a lot of watthours.
52 v is not compatible with geared hub motors. Those are mostly sold in the 36 volt variety these days. I have a geared hub motor & I haul up to 80 lb on hills up to 15% on my cargo bike. 330 lb gross will start on that grade. My geared hub motor is 48 v. It was difficult to find for sale, and the 2 week build time into a wheel stretched to 16 weeks. My current motor is a Mac12, designed with more windings to trade off top speed for more hauling torque. The standard model is the Mac10. Note geared hub motors will overheat and burn a winding if forced to lug at full power up a grade longer than 20 minutes. Mid drives are limited by the European Union to 350 W so they will not accept enough current to overheat themselves lugging a load. Special model high watt mid drives for the US market are rare.
Two batteries and two motors is an expensive way to haul loads. My setup is $1280, $630 for a 48 v 17.5 ah battery and $645 for a Mac12 geared motor. A second controller & battery would be best for a second motor. The Mac12 tops out on 26" wheel at about 23 mph with controller that came from lunabike. Amp limit undefined. The 30 amp controller I own from a previous geared hub motor was not pin compatible with the Mac12 motor.
For more information on mid drive motors compatible with 52 v post a thread on diy kits forum below.
Really with your speed & load requirements you would be happier with a gasoline scooter. Those have up to 4.95 horsepower, much more than a bicycle motor. That is approximately 3.7 kilowatts. I see them blatting around quite frequently at ~35 mph. I won't own one because of the noise. three fourths of the scooters in my neighborhood have worn out the muffler already.
 
Last edited:

Taylor57

Well-Known Member
.Just another new guy from lake havasu city utah...And of course i have a lot of questions.
I bought a schwinn (ya, i know,) 21 speed hybrid...almost brand new. bought a 1500 watt rear hub drive kit and a 52 volt 20 ahr battery. Been ridding it every day for the last two weeks. Seems to run properly. I guess 35/36 on flat is about right? What is i controlt that limits top speed? It limie will pull ok up to 35 mph and it stops pulling...Some kind of speed control limiter in the control unit or is the just the the best rpm it will run with the available voltage? 35 mph is ok but because i am building a small trailer to haul gas and water back to camp i need more power to get up a few small hills i was going to buy a motor for the front wheel. Do i need another one rated for 1500 w or will a 1000 watt with a to do wh to dots own separate 52 volt be enough to do what i want? will one twist throttle control 2 systems?
Thanx jn advance
mike
Lake Havasu Utah or AZ?
 
Region
USA
Welcome to the site.
Direct drive motors perform best at speed. 35 mph is quite fast for any bicycle motor. The limit on a US sold kit is usually the amp limit of the controller. The cheap 1000-1500 w DD motors are typically sold with a 30 amp controller. Batteries have their own amp limit - typically 50.
Hauling is another question. DD motors lose a lot of torque at lower speeds. Two ways to match the torque to a heavier load are gear the motor down with internal gears, or buy a mid drive motor that both has internal gears and a variable speed sprocket set. In addition a DD motor lugging at low speeds wastes a lot of watthours.
52 v is not compatible with geared hub motors. Those are mostly sold in the 36 volt variety these days. I have a geared hub motor & I haul up to 80 lb on hills up to 15% on my cargo bike. 330 lb gross will start on that grade. My geared hub motor is 48 v. It was difficult to find for sale, and the 2 week build time into a wheel stretched to 16 weeks. My current motor is a Mac12, designed with more windings to trade off top speed for more hauling torque. The standard model is the Mac10. Note geared hub motors will overheat and burn a winding if forced to lug at full power up a grade longer than 20 minutes. Mid drives are limited by the European Union to 350 W so they will not accept enough current to overheat themselves lugging a load. Special model high watt mid drives for the US market are rare.
Two batteries and two motors is an expensive way to haul loads. My setup is $1280, $630 for a 48 v 17.5 ah battery and $645 for a Mac12 geared motor. A second controller & battery would be best for a second motor. The Mac12 tops out on 26" wheel at about 23 mph with controller that came from lunabike. Amp limit undefined. The 30 amp controller I own from a previous geared hub motor was not pin compatible with the Mac12 motor.
For more information on mid drive motors compatible with 52 v post a thread on diy kits forum below.
Really with your speed & load requirements you would be happier with a gasoline scooter. Those have up to 4.95 horsepower, much more than a bicycle motor. That is approximately 3.7 kilowatts. I see them blatting around quite frequently at ~35 mph. I won't own one because of the noise. three fourths of the scooters in my neighborhood have worn out the muffler already.
 
Region
USA
I got a check ride today pulling trailer. Empty trailer weighs 44 lbs and runs on 2 14 in motorcycle wheels/tires with the bobbies ground off and 50 psi. 10 gal of water and 10 gal of gas about 130 lbs.probablu 175 total and I weigh. The steepest of the uphills usually slows the bike down to 22 mph..loaded up it was 12 to 15 with a little help from pedaling. Motor got a little warm..maybe 120..the wires to the motor got warmer than I like..ran a voltage drop across each wire..over a volt..that ain't right..why do they run such skinny ass wire? It looks like 18 maybe 20 gauge. I got some silicone 14 gauge like they use on electric rc cars. It has close to 100 strands in each wire. I am going to take it apart tomarrow and replace the wire from the motor to the controler wires connected with 20 amp bullet connectors...see if that makes any difference. I ditched the mountain bike tires for a pair of slicks at 65 psi...good for almost 2 mph..ride is a little harsh..oh well...still thinking about 1000 watt front hub drive. Your parts prices are way higher than mine..52volt 20 ahr battery was 300 and no Chinese cells and rear wheel kit was 220..front wheel deal is a little less and 1000 watt. And I think I can get away with a 52 volt 12 hr battery...nobody seems to know if I can run both controllers with a single twist throttle..I can figure out a way to graft 2 of them together if I have to. Running 2 motors shouldn't affect range I dont think...it takes X amount of amps to roll down the road..anybody run ebike in hot weather? 110* in summer is an average summer day around here...a hot day would be 100* at sunrise and 120* at 5pm..I can stash the bike in the house when I'm not riding..80* I have infrared temp gun to measure heat...what is max temp for motor/battery/controller?
Thanx much for any and all info...I am retired gm service tech, had a m/c repair shop 8 years and now I am building 1000 hp boat motors...I know about nothing about e bike and dont like learning the hard way..lol