Known Issues & Problems with Bafang Products + Help, Solutions & Fixes

[Ann M.]

No ebike is perfect, this is a thread dedicated to sharing known issues or problems with electric motors from Bafang as well as any help and solutions you know of. Sometimes that means a DIY fix and other times it can mean a recall, software update or part replacement by a dealer.

Please be respectful and constructive with feedback, this is not a space for hate speech. In many cases, representatives from the company will see feedback and use it to improve their product. In the end, the goal is to enjoy riding and help each other go further and be safer.

 

[Dana B]

Hi! I'm a newbie in these forums so hopefully I am posting in the right place! I just received an electric bike from M2S Bikes that has a 750W Bafang rear hub motor on it. The issue that I am having is with the battery though, which I believe is an 48 Volt LG 16 amp hour lithium ion battery. I have only been able to take that bike on 3 long rides. On each ride, the battery level never goes below full but the battery completely 'konks' out when I hit the 14km to 16km mark on the bike. Then, when I charge the battery, it only charges for an hour and then shows as full. I am charging it off the bike. It feels like I am only getting use out of the top end of the battery and nothing else. Could this be an issue with the settings on the controller or the computer on the bike?? Does anyone have any feedback on this??

 

[flymeaway]

completely 'konks'

OK...what does M2S say?

What exactly does "konks out" mean? What happens?

Is the motor very hot to the touch when this happens?

If you let the bike sit for 10 minutes does it turn back on and you can ride it?

There are a number of possible issues that might cause the problem you describe. First I'd eliminate operator error. Rear hub motors require some care when riding, for instance, they dislike turning really slowly at high power inputs. If your motor is hot to the touch instead of turning electricity into power, the motor is working too hard and turning energy into heat. The battery probably has a management circuit called a (BMS) which keeps cells balanced and has several safety features including low voltage cut-off. The distance you are traveling shouldn't be enough to drain the battery to the cut-off, but, if you are trying to climb a steep grade at 14/16km with a high power setting the voltage might drop enough to trigger the cut-off. Your motor may have a temperature sensor which will force the controller to shut down if the motor is overheating. You could have a defective BMS, or a cell or cells in the battery that are failing.

My suggestion; ride the bike on a relatively flat grade at low power settings and try to exceed 14/16km, and if the battery still cuts out under these conditions I'd say you have a battery problem, but not necessarily conclusive, but leaning towards the battery.

Court J.

 

[Dana B]

Thanks Court for the reply! Personally, I am leaning towards it being a battery issue as well. I still haven't heard back from M2S Bikes about it yet, have contacted them twice. The motor is not getting hot. Although, I live in a hilly area and my rides are generally very hilly, though staying on the bike paths. I am also only using the 2nd level pedal assist (out of 9 levels). The bike also has a throttle which I only use to get going when I am stopped at lights.

When I say that it 'konks out', I mean that I am given no warning, and the battery just shuts off. I get no warning about this as the battery level shows that it is full. And no, I can't get anymore battery out of it, and I can't turn it back on until I charge it. Coincidentally is quit on me at the same spot both times... and yes, I was going up a slight hill. But I suspect this was purely coincidental as I went about the same distance on both occasions and the hill was much less steep than the hills on the rest of the ride. It almost feels like it quits just before it is about to drop down the battery level, if that makes sense.

This bike comes with a little controller box, along with the motor. I was just wondering if there are some settings in the bike computer that I should be checking, or if there could be a fuse somewhere that needs replacing?

Hopefully I will hear back from M2S Bikes soon. The only trouble is that getting a replacement battery will be difficult. I am in Canada and it took me over three months to receive the bike the first time from their warehouse in North Carolina.

 

[flymeaway]

This bike comes with a little controller box, along with the motor

"I was just wondering if there are some settings in the bike computer that I should be checking, or if there could be a fuse somewhere that needs replacing?" I don't believe this is the issue. A blown mechanical fuse would disable the bike until it was replaced and the controller should be properly configured when it's shipped.

Every Ebike has a motor controller and some form of input device to change settings. I seriously doubt that the controller is at issue, the problem you are experiencing does sound like the battery. I would be surprised if the distributor (M2S) didn't have the controller properly configured. Unfortunately you probably have to wait for M2S to get back to you which can be frustrating. Hopefully they will stand behind the product and work quickly to get you the replacement part you need. Let us know what the resolution is....and maybe someone else reading has a different perspective.

Court J.

 

[john peck]

The only other thing I could suggest in a situation like this is to check the connect0rs in the wiring harness or
possibly an abraded wire shorting out or bad ground?? This being an old post that's probably not much help.

 

[Rob Bay]

I was looking at m2s bikes, specifically the all terrain 750 hard tail due to the nice price for the features you get. Still waiting on the Hyper Fat from Juiced Bikes because I think that will be a beast! Many good reviews on M2S site. I'm curious how the LG 16ah battery rates against the Panasonic, Samsung etc. I do have a fat bike now with a Bafang 750w hub motor and Samsung. Only issues I've had so far sounds like a bearing clicking. Trying to see how hard it is to change them out. Maybe the rear break pad clicking on the disk, I dunno.

 

[J.R.]

I'm curious how the LG 16ah battery rates against the Panasonic, Samsung etc.

LG is one of the top manufactures, if not the top manufacturer of 18650 cells. It can depend on application, but anyway you rate cells, LG is up there.

https://reactual.com/outdoor-equipment-2/power-sources/best-18650-batteries.html

http://www.best18650battery.com

 

[Rob Bay]

Nice thanks! They advertise abt 900 charge cycles which is good enough for me. I don't mind forking out $300-400 every couple years as I spend that on gas for a vehicle in way less time than that.

 

[flymeaway]

like a bearing clicking

Is that on the Bafang equipped bike?

Court J.

 

[Rob Bay]

Yes mine is and I believe m2s is also.

 

[flymeaway]

Yes mine is and I believe m2s is also.

Make sure the crank arms are tight. I have to occasionally tighten the crank arms on the bikes with BBS02 750W motors. I know the bolts are not tight when I hear a rhythmic clicking noise as I pedal. In my case the right crank is always the looser as it's my dominant leg (strength). The 1st time it happened I thought it might be a bearing too.

Court J.

 

[Rob Bay]

Oops clarification: it is a rear geared hub motor.

 

[Guven]

Hi ,

I have a 20inch wheeled bike with a Bafang 500W 36V middrive on. My chainring is 46T and the biggest rear gear is 34T. On flat road on 34T full throttle no pedaling, the highest speed is 16 kmph. (11mph) . On moderate hills it is 12kmph but on a steep hill , the speed is 10kmph and the chainring is spinning so fast that I cannot keep up easily even if I pedal. Is there a safe way that I can increase the rpm of the motor namely my speed on a steep hill?

 

[Jayson]

Maybe need to change BMS of battery?

 

[Pegasus]

Make sure the crank arms are tight. I have to occasionally tighten the crank arms on the bikes with BBS02 750W motors. I know the bolts are not tight when I hear a rhythmic clicking noise as I pedal. In my case the right crank is always the looser as it's my dominant leg (strength). The 1st time it happened I thought it might be a bearing too.

Court J.

I tighten my Bafang crank arms before every ride. They are always coming loose. I understand that it is not a screw problem, but a material problem. The bafang cranks are soft ally and deform on the steel square. "You are going to need a better crank".

 

[tomjasz]

I tighten my Bafang crank arms before every ride. They are always coming loose. I understand that it is not a screw problem, but a material problem. The bafang cranks are soft ally and deform on the steel square. "You are going to need a better crank".

IF they get tightened with the use of Blue Loctite I've never had one come loose. BUT if they've been loose and tightened a number of times they may well be out of spec and fixing requires a new set torqued properly and the use of the Blue Loctite. That said, Buzz Bars, Lekkie crank arms are incredibly popular solution.

 

[tomjasz]

Hi ,

I have a 20inch wheeled bike with a Bafang 500W 36V middrive on. My chainring is 46T and the biggest rear gear is 34T. On flat road on 34T full throttle no pedaling, the highest speed is 16 kmph. (11mph) . On moderate hills it is 12kmph but on a steep hill , the speed is 10kmph and the chainring is spinning so fast that I cannot keep up easily even if I pedal. Is there a safe way that I can increase the rpm of the motor namely my speed on a steep hill?

Why use the 34T on a flat road? 46T x 14T would be faster! OOPS NECRO THREAD.

 

[FlyingFinn]

I broke my 2019 Ultra’s clutch last summer. I had ordered a new main gear and the clutch from Greenbikekit.com. I was very fortunate ordering both since as you see the broken pawl will chew the teething off the main gear.

The set that GBK is selling is the newer 2020 model. The pawls are thicker hence stronger and the clutch is thicker. You can’t mismatch 2019 or earlier clutch with the newer 2020 main gear. I strongly recommend you have one clutch and one main gear in stock as replacement at all times. These will fail. When is the question...

 

[TLC]

No ebike is perfect, this is a thread dedicated to sharing known issues or problems with electric motors from Bafang as well as any help and solutions you know of. Sometimes that means a DIY fix and other times it can mean a recall, software update or part replacement by a dealer.

Please be respectful and constructive with feedback, this is not a space for hate speech. In many cases, representatives from the company will see feedback and use it to improve their product. In the end, the goal is to enjoy riding and help each other go further and