Bafang G310 geared hub - 11:1 reduction ratio!!!

[john61ct]

Interesting idea, would like to see this discussed in greater depth.

Worth its own dedicated thread though

I just built a little throttle cutoff harness for over-volted/watted motors that uses a mini 5v thermostat board, that cuts off the throttle when the motor internals hit 120 degrees Celsius.

LM YN Digital Thermostat Module DC 5V -10℃ to +210℃ Electronic Temperature Control Module Switch Waterproof Sensor Probe Dual LED Display Red+Green

https://www.amazon.com/gp/product/B01M1J64LQ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

The board works off 5v and can use the VCC of the throttle wire to power the board. Then the board relay cuts off power to the throttle when over 120 degrees. Works like a charm.

I made a throttle cable harness that can be easily removed if the board dies on a ride.

The beauty about this is that you can use the throttle wires to both power the board and cut-off the throttle, making it a somewhat clean setup. I prefer this over techniques that cut off power to the motor or controller.

You have to open the motor, epoxy the thermostat to the windings, and poke the wire out of the existing hall/phase hole. Next I'm going to install the board into a clear plastic case to semi-waterproof it.

 

[zukster]

I'll post it to its own thread once I install it into a clear case and take some pictures. Its pretty simple.

Also, for those who are concerned about cutting off the throttle unexpectedly, many of these boards have an alarm buzzer.

When the temp gets above 120 or so, you can set it up to sound the alarm only. You don't have to use the relay. Come to think of it, I might actually prefer that too as long as I can hear it okay. Maybe putting the board under the seat would be loud enough.

Anyway, this is not the thread for this. I'll start its own thread in a bit.

 

[1N4001]

You need to get the wire out where the phase/hall wires come out. If you can't do that, it won't work.

Yes, I'm aware. We are talking about the G310, correct? I can't tell how you managed to route them out.

https://i.imgur.com/mdgisRG.jpg

Here's the stator. On the bottom is where the phase wires come in. I'm assuming you glued your temp sensor onto the coils on this side? How did you route the sensor wires back to the other side? There's little room, seeing as the rotor will be occupying the middle of this assembly. Did you route in between the stator teeth maybe?

https://i.imgur.com/GHw7cmm.jpg

And here's the other side, where we trying to get to. Did you remove all this potting around the phase/hall wires to add the thermistor wire?

Thanks!

 

[john61ct]

I'll post it to its own thread once I install it into a clear case and take some pictures. Its pretty simple.

Also, for those who are concerned about cutting off the throttle unexpectedly, many of these boards have an alarm buzzer.

When the temp gets above 120 or so, you can set it up to sound the alarm only. You don't have to use the relay. Come to think of it, I might actually prefer that too as long as I can hear it okay. Maybe putting the board under the seat would be loud enough.

Anyway, this is not the thread for this. I'll start its own thread in a bit.

Great, just link back to your post above as well.

The ideal is two adjustable setpoints, one for audio/visual alerts, the next for actual cutoff, if not ramping down.

 

[zukster]

Yes, I'm aware. We are talking about the G310, correct? I can't tell how you managed to route them out.
https://i.imgur.com/mdgisRG.jpg

I did this on a Cute 100 CST and may do it on a G370 rear as soon as I can get my hands on another one. I had problems with the G370 I was working on. For the Cute 100, the wires come out the very end of the axle. For the G370, it looked like there was room where the main cable came out. I don't have a G310, but I think its similar to the G370. If you want this to work you need to try to squeeze the thermistor wire through the hole where the main wire exits the motor.

 

[hias9]

To look for a spot for a temperature sensor, I have disassembled the case of my G310 like in Justin's video which was very easy.
However I cannot separate the motor+gear from the freewheel by hand (in the video it works with minimal force). Is this normal?

 

[amberwolf]

is there a circlip retaining ring (may look like a thin washer) on the shaft preventing it?

 

[hias9]

Yes, there is a circlip retaining ring, but it is on the left side (motor/gears side).

The flywheel side looks like this after I have removed the nut:

The metal part below the nut has flats, but it is not possible to grab them.

 

[drdrs]

I had to remove that second nut to get it open. I agree it is hard to access with a normal wrench.

 

[hias9]

Ok, the metal part with the flats was a second nut. There was minimal space to grab the flats, but after that you can easily separate the 2 parts.

Now I am struggling to get the case back on. I just cannot get the bearing on the cable side back to where it should sit. Even not by pressing on a concrete floor or with a 3-arm puller.

edit: Well, it worked by pressing the axle on a concrete floor with some angle to get the bearing on its place on the axle.

 

[rheo]

Where can I buy this thing in a wheel or kit without battery other than grin? nothing against them but I'm in Australia and the shipping from Canada is expensive

 

[hias9]

After my G310 was running a bit without load on the bench (not above 42 kph), it started squeaking.
Do you think it's the bearings which are squeaking?

Videos:
https://streamable.com/rzq58
https://streamable.com/nbtb6

 

[hias9]

My G310 only had one bearing standoff ring on the left (cable) side and none on the right side.
The G310 in the Grin video has 2 bearing standoff rings on the right.

How was it on your G310s?

 

[qwerkus]

Hello, anyone succeeded running a g310 with a kt controller on stock firmware ? Which parameter did you use ?

 

[hias9]

Yes, it is working fine. Do you mean the parameter for the number of magnets (P1)? It should be 16*11.1=178

 

[qwerkus]

Yes, it is working fine. Do you mean the parameter for the number of magnets (P1)? It should be 16*11.1=178

Awesome - thanks! And what do you use as c2 parameter ?

 

[hias9]

I did not change it. I think default value was zero and worked fine.

 

[hias9]

I had a squeaking noise on my G310 which was caused by the black rubber ring on the cable side. I put some silicone spray on it and the squeaking noise was gone, but the rubber ring is not staying in place because it is too elastic. The rubber ring makes one turn about every 30 seconds when the motor is running without load.

Do you guys have the same issues? I think I will just remove the rubber ring.

edit: I have glued the ring to the axle and it is working fine so far.

 

[qwerkus]

Tried it today: g310 + kts controller 6Fet hailong integrated @48V. Pretty much plug and play, though the motor seems a bit noisy when compared to some youtube videos. I'm going to try other c2 parameters. Also, any chance to get pwm speed (p2) somehow accurate ? Right now the display shows only motor speed, which is 0 when coasting or pedaling.

 

[hias9]

P2 should be 6 because it has 6 pulses per turn. It worked fine for me.

 

[qwerkus]

P2 should be 6 because it has 6 pulses per turn. It worked fine for me.

Hmmm. My speedometer stays at 0 not matter what. Tried 2 different displays without success. Could it be a mismatch between the bafang 910 connector and the kt connector (speed signal on the wrong wire?). It proved awfully difficult to plug into each other. Otherwise only explanation would be a defective speed sensor in the motor, but that would be surprising for a brand new unit.

 

[hias9]

For my G310 it was basically plug and play (and set parameters) to match with a KT controller. White cable is the speed sensor cable.

 

[oger]

I got the G310 finall running with VESC.
Pretty good result actually. Real quiet.
But a bit slow.
I'm running a 12s 44v Pack and have 28" Wheels.
Does anyone know how to tell which version of the motor I have?
There are supposed to be 3 versions.
Can I tell by the writings on the motor?
I bought it here:
https://motowoks.com/collections/electric-wheelbarrows-motor-kit/products/bafang-rm-g310-250-dc-rear-drive-motor-250w?variant=22656834568310

 

[mongrol]

Where can I buy this thing in a wheel or kit without battery other than grin? nothing against them but I'm in Australia and the shipping from Canada is expensive

Did you find one?

 

[rheo]

Yeah I bought it unlaced from grin. Had my local bike shop build it into a wheel here. Shipping was a bit cheaper that way.