Bafang RM G310?

adcockj

10 mW
Joined
May 2, 2018
Messages
22
I recently installed a 48v kit on my bike, using a Bafang G020.500W motor and Grin's 20a Grinfineon controller and CA3. It works great, especially after some help I got here on the forum.

The only issue is that it's s little noisy with the motor buzz. I looked at Grin's website and it looks like the G310 would be a good motor to use on my bike, but they don't have any available.

I've found one online, but it's advertised as 250w...it's a "Bafang RM G310.250.DC rear drive motor 250 W 10T 280RPM". Is this same same motor that Grin says is 500w with a 48v battery? Or does Bafang have more than one G310?

Thanx much.
 
I've used that Grinfineon and on a sm. geared motor and it's a hot rod controller. In fact, on the tiny Q100H (Cute), I could feel it start to "hammer" the motor. You might want to try a sine-wave controller around 17 Amps. They are smoother and quieter than the square waves, but the bike will be slower to accelerate, especially off the line. Top speed should be about the same.
Plus, it would be a lot less costly to try and it would be more useful to have an extra "emergency" controller in your spares kit, than an extra motor.
 
The Grin product page explains this pretty well. The motor is rated at 250W, and there aren't different watt ratings for this particular motor, but the wattage does not mean much. Depending on speed the motor can withstand up to 700W continuous before overheating. Voltage mainly affects the top speed.

I have this motor with a sine wave KT-controller, but I think it is not really sine wave at least when motor starts from a stop, as it makes quite noticeable whirring sound until speed is about 15 km/h, after that it is completely silent. It's not too loud to really bother me, but somewhat ruins the stealth of the bike.
 
Perfect. Thanks, ilu. That's what I thought would be the case, but I wasn't sure. I have the 20a Grinfineon sinewave controller, so the G310 looks like the right answer for me.

For motomech: I am using the CA3, so I can limit the amps if necessary...but I'm not having any issues with the G020.500 motor I'm using now.
 
Interesting info on the G310 Motor
https://youtu.be/c96n0Ma2rLY?t=7342
Synopsis in case link goes dud
- Lots of bad issues: Highest % of motor failures and RMAs, magnets, clutch failures, gear failures.

Info before video @ timestamp is MICRO MOTORS MICROMOTORS, very interesting
 
Interesting... I think most of the problems can be traced back to heat as the root cause. Heating the windings and sensors, heating the gears (and excessive torque), heating the epoxy holding the magnets on the rotor enough for them to separate at high rpm. Motor simulator doesn't help the cause with maximum temperature 150C. The original word from Grin was 700W, now reduced to 500W.
BTW, the trip simulator with manual slope input is a more useful tool than the motor simulator for estimating temperature behaviour.

They're a lightweight low power motor to fit EU EN 15194. That's 250W (about 300eW) & 6-25kph pedelec. At that speed limit the motor output is 160-200W. Used within or closer to design it **should** have much fewer problems.
My 311 is kept below 80C, usually running at 60-65C which means pedalling the damned thing (typically average 160-200W, 250-300W uphill, measured with Powrtap power meter - more than average FF), and below 30Nm and 320rpm. Hard limit is 350rpm in a 20". Temperature rollback at 80C, hard limit at 100C although I can reduce that to 90C without noticing a difference, I set the adjustable speed cut off just below the speed I maintain on human power alone which is typical for an EU pedelec. It has about 7000km. Already more than some will be ridden in their entire lifetime, but it is only a few months old and I may yet eat my words. I bought a spare motor just in case.
Controller is a stand alone baserunner. The motor is not silent on the bench. I can't hear it on the road at normal power, but it is about 2m behind me. I could hear it accelerating at 400eW during a few hundred kilometres of testing with logging. With that power it heats up fairly quickly.

I don't run it that high now. The reason I switched from 9C DD to the 311 was that the more efficient and temperature resistant DD drew too much queer eye attention from police and I had to defend it too often. Not the US, eBikes and cyclists in general are soft targets for police here. Give them an excuse and they'll seize it out of spite. Safety is their excuse, but they have an appalling, nearly non existent close pass enforcement record. Go figure... soft targets.

500W should be okay with effective thermal management. The motor needs to be modified for a temperature sensor.

If a rider is only going to use the pedals as foot rests or at best soft pedal and expect the motor to drag them along at 40kph and last more than five minutes then I'd suggest a stronger motor.
 
@TDB: Did you manage to do 7000km with one set of gears? Did you add oil to it?
I also limit to 350wheel-rpm, foldback at 90C, cutoff at 120C (but never been higher than 110C), temperature sensor added next to the speed sensor.
Which winding version do you have and how many phase amps?
My G310 is a 13T and with max phase amps set to 30 (torque equal to 39 phase amps on a 10T), the gears only lasted about 200-300km.
They failed at 90C motor temperature, the case was not hot at all. Seems like the gears got hotter than the motor.
 
Mine is a very conservative setup. Pedal assist with a trailer. Not a motorcycle.

It has original gears. I epoxy (ER2225) coated the windings and boards to protect it from ATF. I'd use EL601 if I had known about it sooner and could get the stuff. Nobody wants to ship it. Standard 10.5Kv wind, 52V pack, 20" wheel, 25A phase limit, 6A battery limit, 240eW power limit set in the controller that keeps it legal inside the 200W mechanical power limit.

I do about 1400m of climbing every day and on a typical day it isn't getting over 66C because I do my part. It runs about 20C hotter without oil.
 
Ok, 25A phase limit on a 8T winding (or is it 10T 8.5Kv?) is very conservative.
Is there some ATF leaking or everything tight?
 
I have no idea the number of turns. I misspoke. Mine is 8.5kV which is the slowest motor.

The motor seals hold oil fairly well. I put a vent in with the wires to an overflow bottle to take the pressure off the seals. Think radiator overflow. It can burp a little when hot and draw it back as it cools.
 
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