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Need help identifying Bafang geared hub motor BFY804B11346

Reid_in_QC

100 µW
Joined
Oct 31, 2021
Messages
8
I have repaired the salvaged Bafang motor shown in attached pics. As you can imagine I got it for free because of severed wire harness - Montreal snow plow special!

I'm putting it on a tiny garden cultivator from the 1940s. I'm an organic vegetable farmer and yes I actually intend to use it to cultivate narrow spaces where none of the other electric walk-behind weeding tractors can fit. Also this project has been a fun educational project for a teenage friend of my daughter's - hence using a broken motor and generally making it more complicated than it needs to be.

So I'm usually pretty good at tracking down this kind of info online but I can't find this motor anywhere. It's definitely Bafang because 8fun on rotor casting but the only other marking anywhere is the BFY804B11364 on the outside case and that doesn't yield any results. I'm guessing it was sold under another brand that's not well documented

It's an older rear hub, designed to be fitted with a freewheel rather than cassette, with geared drivetrain and sprag clutch on the planet carrier. I'm guessing it's about a 350W motor, maybe capable of 500W but I can't really guess from the model number what the kV might be or whether it's wound for 36V or 48V. It was laced to a 26" (559mm) rim but now it's just going to drive a chain then another chain and then some cute little wheels.

Ultimately it doesn't really matter that much as I'll figure it out as I start testing it. If it's too slow (unlikely) I'll find a pack with higher voltage. If it's fast I'll limit it in VESC or tamper with the throttle signal if I'm using a crap controller

I would like to know current limits since it doesn't have a temp sensor and I just like to know specs when I can. Any help would be much appreciated.

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Haven't seen that specific one, but best guess based on size and internals is a "250w" or less motor. Most of those are intended for 15-20MPH max at 24-36v in whatever wheel size they came in. Most likely intended for a 5-10A (battery side) controller.

The marking in red on the stator is probably the winding configuration, in this case it might mean 14 turns, 2 (or 20) wires in parallel in each turn (or 20g wire was used with just one wire in each turn, perhaps).

Anything you can tell us about the bike it came off of could help determine it's characteristics...short of that, testing is the most certain way to find out Kv (RPM/volt).


I don't imagine you'll have much trouble with it in your usage, depending on the geardown you're using vs it's Kv, it will probably have plenty of torque even at low currents, and probably not have issues tilling most soils. (maybe if you have really sticky clay that hasn't been tilled before).

Does the machine have a rotary tiller or is it just a fixed blade pushed along by powered wheels?
 
Amazing details Amberwolf. Many thanks. I hadn't thought to try to analyze the assembler marks in red on the stator.

I'm afraid I don't know what kind of bike it came from as I got it bare and damaged. Your low estimate of battery amps is encouraging as I have a 14A Chinese controller from another e-bike so maybe I can avoid using a useful VESC-capable controller and just use the dumb one (y)

The tiller is just for draft tools and superficial work, no PTO. I'm confident that 250W with planetary reduction and then two stages of roller chain reduction is going to give it more torque than it needs. We did a similar one for a friend using a tiny traction motor from a floor scrubber and even that was enough with the chain reductions. This one ought to be burly by comparison, even at only 10-14 pack amps.

Thanks for the quick reply and helpful insights. I'll post some pics or link to a video when it's done. This is EV number 9 for our farm, including our delivery truck, 4 walk-behind tractors, 2 UTVs and a 4-wheel cultivating tractor.
 
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