36 or 48 V system?

I

Indigeno

10 µW
Joined
Jan 20, 2021
Messages
5
Hi,

sorry for the stupid question, but I could not find clear answers to the preferrable system currency.

I want to fit to my "bio"-bike the xiongda double speed motor 250 W, 230 rpm in the rear hub.
The chain-shift 3 x 7 shall remain. Wheel size is 26 ".
According the law it should be a 250 W motor, max. speed is limited to 25 km/h.
The system weight is appr. 100 kg, 120 kg with baggage

Is the 48V motor more powerful compared to the 36V motor?
What are the advantages: acceleration, peak power ...?
Or is there no difference?

The battery shall have a capacity of appr. 650 Wh

Thank you in advanve for your comments.
 
Pushing you and that full-size back around 48 volts is best.12ah or more depending on range. Are you going to be riding it on flat trails and streets or is this for climbing hills.
 
https://ebikes.ca/
Top menu below Grin Technologies logo - click on LEARN, its a pull down menu.
Some various links from the pull down menu.

https://ebikes.ca/learn/hub-motors.html
https://ebikes.ca/learn/power-ratings.html
https://ebikes.ca/learn/why-hub-motors-are-awesome.html

more info on motors, power, watts
https://www.youtube.com/watch?v=IxB2j-egWcQ

even more info
https://www.youtube.com/channel/UCbKIWz7uAeDSMgulTonKk6w/videos
 
Indigeno said:
xiongda double speed motor 250 W
According the law it should be a 250 W motor, max
Is the 48V motor more powerful compared to the 36V motor?
Click to expand...
If the wattage is the same, they should have the same power, because watts is what is used to measure power.

If one is more powerful than the other, then one of them is not 250w. ;)

Since watts = volts x amps, the higher voltage unit would pull less amps from the battery, so a less-capable battery wouldn't be worked as hard as it would with the lower voltage unit (assuming the same cell capability (c-rate) and number of parallel cells, but just more cells in series for higher voltage).
 
in general, you choose 48v because you want more speed, and more wattage, from a given amperage controller.

Your watts are limited by law (but I'd ignore that). Speed though is noticeable by the police, so the best way to keep that reasonable would be to choose 36v.
 
Dear All,
thank you very much for the useful information! It was very helpful and I decided to go with the 48V system.

@999zip999
80% is on flat tracks, the rest is hilly forest and sometimes I need to get out of my valley on asphalt road, appr. 15% inclination, appr. 200m elevation. And with these 15% I have my problems now without motor support.

@markz
The information by Grin are very useful. Unfortunately I didn't get into it before. Thank you!

@amberwolf
Good point concerning the batteries (voltage/amperes), I was not sure how the amp drain is influencing the battery on the long run.

@dogman dan
With 48V I am on the safe side. And yes, I think to choose a 350 W motor.
 
Indigeno said:
Is the 48V motor more powerful compared to the 36V motor?
What are the advantages: acceleration, peak power ...?
Or is there no difference?
Click to expand...

Careful -- Chinese sellers advertising the same motor at different volts can be referring to different kV (winding) at an arbitrary speed. In this case:
the 36V will have a higher kV (faster for same voltage) and lower kA (less torque for same current)
the 48V will have a lower kV (slower for same voltage) and higher kA (more torque for same current)

Most properly, you'd model your entire system before deciding. But if you're limited to 25k/h anyway, the higher torque 48V motor would be desirable.
 
This is the Xiongda two speed motor? If you buy it from Xiongda as a kit, it appears you get a dual voltage controller. with the switch to change speeds.

Let us know how it works. The initial release of this design had poor reliability reports in this forum.
 
Yes, they offer the controller for 36 and 48 V. There is probably a sensor which checks the battery voltage.

The double speed motor is not very common. But the few users which I know are happy with it. The problems at the beginning were mainly related to the freewheels resp. planetary gears.
I will report.
 
I was/am between setups and needed a hub system fast for a reasonable price.

I found one on Amazon: 36v front hub motor with controller and wheel built, delivered for $203 US - delivered in 4 days.

I installed immediately and upvolted to 48v without even thinking about it.

I deliver beer for a brewery on a bullitt - so I am loading 200 pounds in the front and moving my 200 pounds routinely throughout my shift. I hammered the motor at 48v Superbowl saturday and the motor performed without a hitch.

https://endless-sphere.com/forums/download/file.php?mode=view&id=287692
 

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