Found an incomplete ebike at a thriftshop

damorgue

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I noticed a bike at a local thrift shop with what appeared to be a hub motor in the front wheel. A quick glance and I concluded that it was missing the battery and esc, but motor throttle and brakes with electrical sensors were there. It was also a foldable aluminium frame in excellent, although dirty, condition. Imagine my surprise when I saw it was priced at approx 6$! I have no idea if it works, but I figure the sadle alone was worth that, so I bought it.

GhEdM9v.jpg
TO0jBG2.jpg

Some more images, will take better ones in the following days as I clean it, measure and label the wires:
https://imgur.com/a/Th9pClM

It appears homebuilt, but missing battery and esc. I have been salvaging 18650 cells from laptops for a while, intending to build an electric longboard, but do not have enough yet.

It has a three phase motor, with threelarger wires for power and the standard 5 wires for hall sensors. There are wires coming from the handlebar brakes that are connected to eachother, presumably for regenerative braking. There is a twist-throttle with several wires, a red toggle switch, and an unwired black push-hold switch.

I am currently contemplating buying a battery and esc for it, but am not sure if the motor runs or the specs of it.

A) How do I find out the specs of a completely unlabelled motor? I have gone over it in detail and not found even a serialno.

B) How can I determine if the motor runs without investment? I have some lab powersupplies that, although not powerful enough to run at full speed, should be able to veryify that it moves at all perhaps? I assume I will need at least some sort of ESC too hook up to my lab bench psu. Should I just guess the motor being rated at 250W and get like a 36V 10A ESC? Would it be a better idea to get a 48V 20A ESC and just run it at 10% throttle to test with?

What is the best way to approach this mystery bike?
 
Check the frame joint and steering hinge for play, assess whether the bike fits you or the person you want to ride it. There's a strong likelihood that you bought a hub motor for $6 and got some scrap metal for free with it.
 
Looks like a standard ol' 9C clone that's been around since the late 2000's. Same motor as many ebay specials. You will need a 3 phase controller to test it, and of course that means doing custom wiring.

There was probably a fine reason why this was abandoned. This bike is upright and you have a very powerful motor in a small wheel on the front. There are traction and safety issues here since the power is applied to where the rider weight does not compress the tire to the ground. It will slip on a turn very easily, and since your weight is on the back, you can't use your body to correct the slip. Off the bike you go.

This is the worst kind of front wheel drive bike and a 200w geared motor would be more appropriate for the front, but even still, it may slip when power is applied and you hit a patch of sand or whatever.

Looks like the former owner put the battery up front to help with the weight bias but this frame looks like it's had it's share of road rash..
 
Thanks for the replies. I am not sure whether to complete it, or take the hub motor from it to reuse in some other project. I guess I could respoke it to a different wheel but it seems like a loot of effort if it is just a 200w motor that may or may not work.

It looks fairly identical to this one, especially those 6 reinforcement ribs near the centre on one side and the overall shape/bolt positions.
hub-motor-500x500.jpg

https://www.indiamart.com/proddetail/e-bike-hub-motor-13959045055.html

It is listed as 48V 250W, but I assume the same casing might have been used for many different specs and this is moot.

Hmm, what to do, what to doo. What if I connect a lab psu to one of the phases with the wheel in the air. The motor should want to turn to the nearest 60 degrees to line up that phase, right? Would that be a decent first start to check the windings?

As for the condition, I actually pedaled it home from there and did not notice any issues (other than the motor being heavy and offering some resistance). From what I gather, all the wiring is still there and goes to the battery/esc mounting plate where they were cut of. Buying a random chinese ESC costs next to nothing, but I would rather avoid the cost of a battery if this project is crap from the getgo anyways.
 
That is a 9C or a 9C clone which can be a pretty fast motor and be used at fairly high voltage. Where are you located? If you were near me I would be happy to bring a battery and controller to test it for you. I’m in Arizona.
 
Hwy89 said:
That is a 9C or a 9C clone which can be a pretty fast motor and be used at fairly high voltage. Where are you located? If you were near me I would be happy to bring a battery and controller to test it for you. I’m in Arizona.

I doubt you want to take him a battery and controller since his profile says he's in Sweden, but I'm in Copenhagen so if you happen to be in Malmö then I'll be happy to test it out for you
 
I am in Gothenburg unfortunately.

My current plan is to buy a cheapo generic chinese ESC capable of 36-48V 10-20A or thereabout. I then plan to hook it up to a PSU, which even if it is only capable of a few amps, should still be able to run it at a few percent throttle to see if it works and starts spinning in free air. If it does, I will get a bettery and somehow try to find out the correct specs based on if it gets too warm or something? If I end up running it too hot I will just end up using part of the ESC's capacity which won't be a big waste I guess.

Is it reasonable to assume it to be rated for 250-500W at 36V or 48V?

Would there be any harm in getting an ESC rated at 48V 20A, ie suitable for a 1000W motor, and limiting the throttle to 50%?

I suspect that the first thing that will happen if I get it up and running is that I will start a new build using a much bigger motor and a proper mtb frame.
 
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