Looking for best value DD motor kit on ali express

eecsflyer

10 mW
Joined
Apr 11, 2020
Messages
27
I am hoping to put together a couple e-assist handcycles for a project I am working on with a non-profit in Ukraine. I recently built a couple handcycles using motors from Grin Tech, which are great and have helped me get to places I never thought I could go, but they are too expensive to be realistic in Ukraine. My goal is to build some demonstration bikes that the growing population of spinal cord injured war survivors could potentially leverage once the war is over.

For those interested, you can find more details on what I built in this video, https://www.youtube.com/watch?v=85ST3CPlG94. If interested more, you can also see what we are building in California at ablebodied.org..

I am looking for a rear motor that can fit a 135mm x 10mm dropouts

I would say a stack ranked list of features

1. Compatibility with BB7 disc brakes (enough clearance for the calipers)
2. Has a torque arm
3. Thumb throttle
4. Will not overheat when going up hills
5. Has regenerative braking
6. Ability to set a top speed in the computer
7. Ease of operation

So far, this is my favorite candidate, https://www.aliexpress.com/item/1005001941512775.html

Beyond any tips, any warnings about using these kits? Naturally in a handcycle that the user cannot get out of and walk, robustness is fairly important..

Thanks a lot for the help!
 
Looks like you're looking for a whole kit, not just the motor.
1. What size of wheel are you looking for these to come with?
2. Does it have to be AliExpress? Looks like you're in California...
 
A few comments that may adjust some of your scope or expectations.

eecsflyer said:
I am looking for a rear motor that can fit a 135mm x 10mm dropouts Most standard rear DD hubs are sized for 135mm, unless they state "fat" in the description.

I would say a stack ranked list of features

1. Compatibility with BB7 disc brakes (enough clearance for the calipers) Most 1000W or smaller DD motors are 9C clones, which have clearance for the BB7. Your washer configuration is important for lining up the caliper (if you skp the inner washer on the axle).
2. Has a torque arm best to purchase separately, since the arms that come in kits are crap.
3. Thumb throttle
4. Will not overheat when going up hills Since nobody knows how steep the hills are, it would be good for you to test a few 9C clone motors in the Grin simulator, and enter in different bicycle weights and grades for the hills to see whether the motors overheats. https://ebikes.ca/tools/simulator.html?motor=M2706; or provide actual grades (not guesses); it will also inform you about how the different motor winding affect performance, heat, etc.
5. Has regenerative braking
6. Ability to set a top speed in the computer
7. Ease of operation

So far, this is my favorite candidate, https://www.aliexpress.com/item/1005001941512775.html I wouldn't limit to aliexpress unless you have a specific reason. You can get similar pricing on ebay. I've never had a really bad experience purchasing from aliexpress, but it's not my preference to wait to see if there some sort of import duty tacked on once it arrives, so I don't like the anticipation. Plus it's slow.
 
thundercamel said:
Looks like you're looking for a whole kit, not just the motor.
1. What size of wheel are you looking for these to come with?
2. Does it have to be AliExpress? Looks like you're in California...

I am looking for a 26" wheel. Reason for AliExpress is they have a lot of sellers with warehouses in Europe. My goal is to build a handcycle Ukranians could reproduce themselves. Cost is also a consideration..
 
E-HP said:
A few comments that may adjust some of your scope or expectations.

eecsflyer said:
I am looking for a rear motor that can fit a 135mm x 10mm dropouts Most standard rear DD hubs are sized for 135mm, unless they state "fat" in the description.

I would say a stack ranked list of features

1. Compatibility with BB7 disc brakes (enough clearance for the calipers) Most 1000W or smaller DD motors are 9C clones, which have clearance for the BB7. Your washer configuration is important for lining up the caliper (if you skp the inner washer on the axle).

So I should go 1000W or smaller?

2. Has a torque arm best to purchase separately, since the arms that come in kits are crap.
Where is a good place to buy them? Do most motors come with a shaved down 14mm axle so that it fits into 10mm dropouts?

3. Thumb throttle
4. Will not overheat when going up hills Since nobody knows how steep the hills are, it would be good for you to test a few 9C clone motors in the Grin simulator, and enter in different bicycle weights and grades for the hills to see whether the motors overheats. https://ebikes.ca/tools/simulator.html?motor=M2706; or provide actual grades (not guesses); it will also inform you about how the different motor winding affect performance, heat, etc.

ok thanks, just don't know which motor to input? Just a 9C?
5. Has regenerative braking
6. Ability to set a top speed in the computer
7. Ease of operation

So far, this is my favorite candidate, https://www.aliexpress.com/item/1005001941512775.html I wouldn't limit to aliexpress unless you have a specific reason. You can get similar pricing on ebay. I've never had a really bad experience purchasing from aliexpress, but it's not my preference to wait to see if there some sort of import duty tacked on once it arrives, so I don't like the anticipation. Plus it's slow.

I am looking for a seller that sells in Europe. Particularly Poland and Ukraine
 
These kits are pretty generic in that price range. The best would likely be the one you can get, meaning the kit is located in a place not in covid lock down, or war related shipping issues.

Price would be secondary, at least in the prototype stages.

Re #4, the larger the wheel, the less weight it can haul up a really steep, long hill without overheating. Really steep and long would be something like 3 miles long hill, with 5 to 8 % grades. In 26" wheel about a 300 pound limit, bike, battery, motor, rider, cargo. But in 20" wheel the limit is closer to 400 pounds. People are kinda big these days.

But happily, to my limited knowledge of the Ukraine does not have the long steep hills. Sure, each valley may have a good steep hill down to the river, but nothing like the mountain I used to test motors till they melted. Motors can get a lot hot going up a short steep hill, but then have time to cool on the downside. Rolling hills are not as big a problem as mountains.
 
Good point about the lack of mountains. I live in California where the story is different.

With hill performance being less of a concern, I have narrowed down my search to a couple geared motor kits that seem like they could do what I need

This kit https://www.aliexpress.com/item/100...d16515175180897773e5b62|12000028137024230|sea seems nice as I may be able to mount the ebrake and throttle on the pedal handle and route one wire along the brake cable.

This one seems nice as the controller seems more generic and I think Bafang motors have a pretty good reputation
https://www.aliexpress.com/item/32968170843.html

Anybody have any experience programming these displays/controllers? I need to be able to set a pretty low top speed for safety reasons..
 
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