Bafang bpm

Kurt

Kurt

10 kW
Joined
Apr 21, 2008
Messages
962
Location
South Australia
I am looking to build a Bafang BPM motor into a 20" wheel and I am trying to work the bafang BMP motor data out. I want the highest KV motor as I am using a 20" wheel .

I was able to find this info on a google search about the code /winding? of the motors but unsure if its correct.
• Code 9 is 340 rpm
• Code 10 is 310 rpm
• Code 11 is 285 rpm
• Code 15 is 206 rpm

I was looking at the info on the Evassemble wepagehttp://www.evassemble.com/index.php?main_page=index&cPath=17_4 and below is the spec of what I guess is a code 9 for $139 I am taking a guess that there motor rpm listed at 340rpm is taken at 36v? and there speed is taken from 26' wheel and the variation of 35 - 42kph is the difference between 36v and 48v.

Product Description:
Bafang 500W BPM Permanent Magnet Sensorless Motor (Popular in Europe)
Product Model:BPM
Voltage:36V or 48V
Rated speed:35-42 Km/h
Power:500W
Wheel size:20'24'26'28'
Rated rpm: 340 r/min
Weight:4.9KG

Dose anyone know if the code 9 is the lowest wind? Also It looks like the motors are senseless but I have read you have the option to order them censored with halls fitted?

Anyhow I am just looking for the best Bafang BMC motor for a 20" wheel and pref to have one with halls. Buying from Australia.


Kurt
 
The motors are sold both sensored and sensorless. My Code 13 ran 21.5mph(34kph) w/ 48V and 26" wheel. Great motor, strong and quiet. Don't know, but suspect code9 is highest Kv. I've only seen codes 13 and 14.

Just be wary of buying a controller with the BFM. I've found common controllers are compatable. Either way, your wire colors probably won't match the controller. Blue to blue, switch the other 2 has a good chance of being correct. My 2 motors both weighed 4.3Kg.
 
Thanks for that SoSauty .

Sorting out the controller wiring isn't a big prob for me just finding the motor spec info to work out what configuration that is going to work best is.
After doing some more searching I think there is a code 8 as BMS battery are listing a 393rpm version of there 500w Bafang BPM, but only in a Front motor option. Dosn't give you the option on there page to select halls or not.

393 rpm wouldn't be to bad in a 20" wheel. would give about 36kmh .

I cant find the manufactures web page or something with all the information and motor codes.

Kurt.
 
393 rpm wouldn't be to bad in a 20" wheel. would give about 36kmh .
Click to expand...

393rpm = 23.3mph = 37.6kmh...on paper, using a 20" diameter wheel+tire.

This is rough but probably close enough...
C11 @ 48v = 16.9mph
C10 @ 48v = 18.4mph
C9 @ 48v = 20mph

At 96v...
C11 = 33mph
C10 = 36mph
C9 = 40mph

I'd probably get a C10 and shoot for 72-84v which should give 27-30mph....roughly.
 
I'm not looking to run that kind of voltage. I am thinking more along the lines of 48 - 60v max more likely 48 volt perhaps 40ah max controller. whatever combination keeping it under 1500w.

They don't make it clear if the RPM is at 36v or 48v it looks like a code/wind 8 would be fine if its 393rpm it's just under 40kmh in a 20' wheel especially if that RPM is quoted at 36v as it would give just under 50kmh at 48v

The hard part now is working out who can sell me a BPM code 8 or 9 rear wheel with hall sensor option?

Kurt
 
They don't make it clear if the RPM is at 36v or 48v
Click to expand...

I missed that, sorry. What I posted before was assuming the rpms you quoted were achieved on 48v.

If they're achieved on 36v;
C9 = 9.4 rpm/v
C15 = 5.7 rpm/v

If they're achieved on 48v;
C9 = 7 rpm/v
C15 = 4.2 rpm/v

My guess is that the rpms you quoted are done at 36v, not 48v. 9.4 rpm/v seems more plausible for a "fast" motor than 7. Just a guess though.
 
Kurt said:
The hard part now is working out who can sell me a BPM code 8 or 9 rear wheel with hall sensor option?

Kurt
Click to expand...

Hi Kurt, I bought a couple rear wheel BPMs with sensors in all black finish from BenMoore in Melbourne. He has stocks of motors from code 9 through code 12.

The code 12 motor runs 42kph 14s Lipo on 26x2.5 tyres.

Ben is a member of the board, but is a little hard to get a hold of, he is very good to deal with however. I have his contact details if you need them.

cheers,

Brian
 
briangv99 said:
Kurt said:
The hard part now is working out who can sell me a BPM code 8 or 9 rear wheel with hall sensor option?

Kurt
Click to expand...

Hi Kurt, I bought a couple rear wheel BPMs with sensors in all black finish from BenMoore in Melbourne. He has stocks of motors from code 9 through code 12.

The code 12 motor runs 42kph 14s Lipo on 26x2.5 tyres.

Ben is a member of the board, but is a little hard to get a hold of, he is very good to deal with however. I have his contact details if you need them.

cheers,

Brian
Click to expand...


Thanks Brian, that's exactly what I was looking for would be great if you could PM me BenMoore's details. He sounds like my best option.

Kurt
 
Any updates?
 
At this stage I have the contacts to get the motor local .

I am about to try running the rc drive that's on my trike now on 15s lipo. If I like the lipo and the voltage. I will have the option to buy a slower wind hub due to the extra voltage of the 15s lipo. So I want to take that voltage into consideration befor making a decision on what code/wind to order.

I will end up with a bafang bpm soon. My wife has a aluminium frame full suspension electric folding bike. It uses a brushed geared hub in a 20" wheel. I would like to do a motor upgrade to brushless on this bike . My thinking is if I don't like the bpm on the trike and want to stick with the rc drive . I can always make good use of the bpm hub motor on her bike.

Will update when I take action and make my mind up.

Kurt
 
I have just ordered what I believe is the Code 10 motor, for use on a 20" rear. The 48V kit is listed as 393 rpm. I believe this is equivalent to the 310rpm motor listed for 36 volts. Should have it in a couple of days. It's going on a Catrike.
 
chvidgov.bc.ca said:
I have just ordered what I believe is the Code 10 motor, for use on a 20" rear. The 48V kit is listed as 393 rpm. I believe this is equivalent to the 310rpm motor listed for 36 volts. Should have it in a couple of days. It's going on a Catrike.
Click to expand...

You will love the motor. Just make sure you never feed it more than 30-40A @ 36V to keep it reliable.
 
Hmm I have been feeding my code 9.. 45 amps at 60v :lol: It doesn't get hot in a 20" wheel under normal use. I have pulled it down after 400 km and no visible wear on the gears. Will see how we go.

Kurt
 
Kurt what kind of speed are you getting with code 9 in a 20" @ 45 amps at 60v?
Hmm I have been feeding my code 9.. 45 amps at 60v It doesn't get hot in a 20" wheel under normal use. I have pulled it down after 400 km and no visible wear on the gears. Will see how we go.
Click to expand...
 
max speed hot of the charge 60v 15s lipo is 50kmh.Then it settles down to around 48 kph once the surface charge is reduced. Even the code 9 is still a slow wind for a 20" wheel. It would be painfully slow on 36v perhaps 30 or so kph.

Kurt
 
Running a geared motor at more than 450-500 rpm may introduce additional parasitic stator losses and some controllers may ever run in trouble trying to handle the amount of ERPM thrown at them.
I tested a code8 and code10 front sensorless BPM a while back on my bench, using a 15S lipo pack and bmsbattery 9fet, and came to an interesting conclusion.
While the code10 reached exactly 8.2 per volt as rated by manufacturer, the code8 was a bit faster but only got to 7.8 rpm/V. Likewise the limiting factor was ERPM of the bmsbattery controller. A sensored motor should handle better and be more quiet, so I suggest you buy a rear motor which should be supplied with halls.
 
Thanks kurt for answering my question,
Not bad for a kit that cost $189.00 from BMSbattery. Are you running a different controller or the stock 12fet controller offered with the kit?
The link below is a kit that you can choose an rpm of 393 and it comes in 16"~28" whole kit from BMSbattery. Is your hub motor the black? or Silver?
where did you get yours from?
http://www.bmsbattery.com/ebike-kits/348-bafang-350watts500watts-bpm-motor-e-bike-kit.html
 
Racer_X said:
http://www.bmsbattery.com/ebike-kits/348-bafang-350watts500watts-bpm-motor-e-bike-kit.html
Click to expand...

Forget about the kit unless you're ready to pay couple hundreds for EMS shipping alone. You have to order motor, spokes and other bits (excluding rim) separately and have it shipped by DHL or Fedex for much less, and still very fast given the distance. To get the required spoke length, use ebike.ca spoke calculator. It even has preset values for the BPM. In my experience, ordering 2mm longer spokes than required is spot on for BPM. Finding a strong 36H rim to fit the length of spokes they have in stock is tricky sometimes, but you can always use quality BMX spokes when building 26" wheel. Most of them are better than bmsbattery stuff and they are very similar in length. Consult your bike shop in advance to make 100% sure.
 
Interesting about the limited function of the controller. I currently have the bpm sensorless running on 12s lipo.
Code 12 in a 700c (29inch) wheel. Really world speed with pedalling is roughly 25mph nominal. Little bit quicker when hot off the charge.

I believe its about 6.9rpm per volt on a code 12.

I've thought about running an additional 15s lipo but come to the conclusion mid twenties is fast enough on a geared hub and hybrid bike.
This setup with a 9 fet controller pulls about 1100 w peak (around 22 - 24amp peak)

If I pushed it to 15s lipo I could probably hit the early 30mph limit given losses in the system the additional drag.
 
I am using a 12 fet 48v 45A 9C controller - basic a 12 fet infineon controller. I got the motor from a local guy who is a member of the sphere. The motor was fitted with hall's so no issues with RPM limitation. I build the wheel myself using a quality 406 BMX rim and custom spokes.

Kurt
 
+1
Thanks Kurt.
Click to expand...
That little hub motor is pretty tuff. Not you your average mini geared you would expect. Thanks for sharing.
 
BTW where do you guys get spare gears from? Apart from the front being sensorless, the lack of spare part sources has been the greatest let down for me, particularily keeping me from running them at higher power levels than 1200-1500W input.
 
I've not read about anyone killing these motors yet. I'm sure they won't be as strong as the macs but no one has really pushed them.
 
You can kill them like any electric motor just feed them enough watts for enough time and you will cook them. That said burst power of 500% of there rating - 2700w and more sustained power of 300% - 1500w up long hills. I have tyred 40km country rides hunting down the steepest hills and climbs I have tyred doing the same towing a child trailer. Its about all I can do to torture test mine. For any situation I'm going to throw at it its capable in a 20" wheel.

The only damages motors of this kind I know of its the axle that had failed due to it not being fully supported. if your not jumping the bike off-road then I don't think this will be a issue for most.

About the only bad thing is they do get a little noisy when you start feeding them hi voltage but its not high pitched like a RC motor so I can live with it.

Kurt
 
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