I have two identical appearing Shengyi 36V, 350w front hub motors built with identical spokes and 26" rims. Operating them with a 15 amp controller and 36V, 17.5 a-h battery, highest PAS level, one goes 23.1 mph and one 20.1 mph on the stand (no load), so apparently different winds. I a$$ume the "slower" one should have better hill climbing prowess. Correct?
Shengyi Motors
- Thread starter 2old
- Start date
SlowCo
1 MW
2old said:
Put one in the front and one in the rear for a 2wd bike. Then it will climb just as good or even better than your BBS02! 8)
liveforphysics
100 TW
If they have identical copper fill, they climb with equal efficiency no matter the windings Kv.
The lower kV unit will potentially reduce controller losses.
A 1 turn climbs with exactly the efficiency of a 10 turn, and it draws no added power from the pack to do it, but it does place more burden on the controller to buck the pack voltage to the voltage the motor uses during the climb.
The lower kV unit will potentially reduce controller losses.
A 1 turn climbs with exactly the efficiency of a 10 turn, and it draws no added power from the pack to do it, but it does place more burden on the controller to buck the pack voltage to the voltage the motor uses during the climb.
SlowCo
1 MW
2old said:
Then use one in the front and the other as mid drive on the same bike:
https://endless-sphere.com/forums/viewtopic.php?f=6&t=38553 :wink:
Or use the front in the rear. Squeeze the dropouts together if you need to to make the axle fit. If you need a pedal chain but don't change gears much, keep the triple on the cranks (and leave teh derailer on the rear as a tensioner) and use a singlespeed freewheel on the rear, by adding a threaded flange like this:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=37837&hilit=front+rear
https://endless-sphere.com/forums/viewtopic.php?f=30&t=37837&hilit=front+rear
liveforphysics said:
Agree that the difference in overall efficiency will be miniscule, only due to slightly increased switching losses (assuming identical controllers).
But maximum torque may be higher on the slower motor at very low speeds because the same maximum phase current can drive the slower motor at higher voltage, thus producing more power.
