Bafang m820

[mike_kelly]

from Greenbike
"
The M820 gaskets have arrived.
If you are from the US, please order asap and choose DHL/UPS for shipping; this Friday is the last day we ship to the US by DHL/UPS/Fedex.
We will stop US shipping from next week temporarily for small parcels. Larger parcels for motors and batteries are still available but freight would be increased due to the US tariff policy.
For M820 gaskets, please order from here https://www.greenbikekit.com/bafang-8fun-motor-parts/m820-m800-motor-parts/bafang-m820-g532-motor-gasket.html
Best Regards!
Ms Anna Lee
www.greenbikekit.com
[email protected]"

 

[borysgo2]

Is there anyone running 48V firmware with 14S 52V battery ?

Thanks

 

[Waynemarlow]

Is there anyone running 48V firmware with 14S 52V battery ?

Thanks

Yes, what would you like to know ?

 

[borysgo2]

Yes, what would you like to know ?

I presume You are running 14S battery on M820 motor. Just wondering if there is no any unexpected problems while using and charging.
Which exactly 48V firmware are You running?
What is max power displayed and how about range.

Thanks

 

[Waynemarlow]

Not sure of the version, I'll fire it up later and check. Max power is a tad disappointing at 560W's, but that is enough for my purposes as a summer packed hard trailly type of use where I'm mainly in that 300 - 500W's max useage.

Range is much like how long is a piece of string, just so many variables that you cannot quote range and those who do usually are talking a load of bollocks. Is it in my view more or less effcient over other motors, can't even hope to offer that nugget unless I had access to some pretty comprehensive dyno type of engineering equipment and 99.99% of YT presenters do not have this.

A bonus is that the M820 unlike the M510 I have can distinguish that the battery started with 58.6 volts and will give abroadly accurate display of battery percentage.

Couple of weird things so far mainly with the Go+ App when transferring between M820 and M510 of zeroing out some parts of the setup, it can't workout that you are no longer riding the M510. Haven't spent much time investigating this and will look into it further when I get a chance.

Charging wise, I have a home built battery with its own 52volt fast charger, I can't comment on your particular setup.

Biggest downside is the M820 is comparably much noisier than the M510 I have. I'm hoping that as it wears in abit ( I've only done 250miles on this one ) it will quiet down a tad.

 

[borysgo2]

Not sure of the version, I'll fire it up later and check. Max power is a tad disappointing at 560W's, but that is enough for my purposes as a summer packed hard trailly type of use where I'm mainly in that 300 - 500W's max useage.

Range is much like how long is a piece of string, just so many variables that you cannot quote range and those who do usually are talking a load of bollocks. Is it in my view more or less effcient over other motors, can't even hope to offer that nugget unless I had access to some pretty comprehensive dyno type of engineering equipment and 99.99% of YT presenters do not have this.

A bonus is that the M820 unlike the M510 I have can distinguish that the battery started with 58.6 volts and will give abroadly accurate display of battery percentage.

Couple of weird things so far mainly with the Go+ App when transferring between M820 and M510 of zeroing out some parts of the setup, it can't workout that you are no longer riding the M510. Haven't spent much time investigating this and will look into it further when I get a chance.

Charging wise, I have a home built battery with its own 52volt fast charger, I can't comment on your particular setup.

Biggest downside is the M820 is comparably much noisier than the M510 I have. I'm hoping that as it wears in abit ( I've only done 250miles on this one ) it will quiet down a tad.

Thanks for info.
The main reason I ask is, because I am planning to build a long distance rig with max battery capacity. Was a bit torn in between M510 vs M820.
Never had M510 so do not know how abut efficiency per kWH vs M820 at roughly same middle assist mode, let me say T or S.

 

[Waynemarlow]

Thanks for info.
The main reason I ask is, because I am planning to build a long distance rig with max battery capacity. Was a bit torn in between M510 vs M820.
Never had M510 so do not know how abut efficiency per kWH vs M820 at roughly same middle assist mode, let me say T or S.

With all the latest Bafang motors using either the App or BESST tool you can change the max Watts on any particular setting. If you want max range then simply cut back on the max watts, the diffence between efficiencies of each motor will be tiny.

I was a " lightweight " fanboy but with all the latest motors being in the 3.kg range, the frames all pretty comparable in weight, the tyres with anything like durability and with anti puncture all around the same weight, then the only real diffence in weight being the battery size. With that in mind would I buy a M820 again to save the 0.5kgs over a M510, probably not.

 

[BenCatalan]

Hello,
Does anyone know/ runs a specific firmware which does not reduce drastically the assistance around those 25%?
I was a bit worried about the possibility today as it was a long ride back home with my daughter on the Shotgun and her bike hooked on the bikepack … well, it turns out to be ugly to be let down in these circumstances

 

[borysgo2]

Have a weird problem with my M820, in order to turn it on I have to reconnect power supply to the motor (BMS-BLUETOOTH-OFF-ON). Before it was intermittent, but now I have to OFF/ON power supply every time to turn the motor on.

Firmware was trashed-but still the same situation. Cables look OK. No moisture on the connectors.

Any suggestions?

 

[mike_kelly]

Hello,
Does anyone know/ runs a specific firmware which does not reduce drastically the assistance around those 25%?
I was a bit worried about the possibility today as it was a long ride back home with my daughter on the Shotgun and her bike hooked on the bikepack … well, it turns out to be ugly to be let down in these circumstances

You have to know that the 20% battery is for protection. A lithium battery can be damaged if it is discharged too low. Or at least the lifespan is rediuced. Now exactly what voltage is too low is a religous thing.

 

[mike_kelly]

Have a weird problem with my M820, in order to turn it on I have to reconnect power supply to the motor (BMS-BLUETOOTH-OFF-ON). Before it was intermittent, but now I have to OFF/ON power supply every time to turn the motor on.

Firmware was trashed-but still the same situation. Cables look OK. No moisture on the connectors.

Any suggestions?

Only thing I can think of is that some BMS have an automatic sleep mode. If the battery is not used for a certain period it puts the battery in storage mode. You then have to apply a charger to "wake" it up.

 

[borysgo2]

Only thing I can think of is that some BMS have an automatic sleep mode. If the battery is not used for a certain period it puts the battery in storage mode. You then have to apply a charger to "wake" it up.

It is not the bms issue, I have eliminated that. Besst can communicate the motor while I can not turn it on. Bms is supplying the power OK.

In other words, after power reset I can turn the bike on only once.

 

[mike_kelly]

I am saying the storage function might be "stuck" on.

 

[Hcastro]

Have a weird problem with my M820, in order to turn it on I have to reconnect power supply to the motor (BMS-BLUETOOTH-OFF-ON). Before it was intermittent, but now I have to OFF/ON power supply every time to turn the motor on.

Firmware was trashed-but still the same situation. Cables look OK. No moisture on the connectors.

Any suggestions?

Hello,

I´ve exactly the same issue already at 2 month.... i´ve been in contact directly with bafang sevral times trying find what is the cause.
Firstly was replaced te comunication cable between display and motor (Cable was ok), then the battery was sent to a techinal center to check (battery was OK), after that it was replaced and teted with a new display (display was OK). At the end of those first check´s, Bafang decided to ask me to send the motor to their technical support and the sittuation until now is the following:

1- The motor was sent to Bafang for intervention and supposedly it was replaced the controller. After receive the motor intervened it was tested and the problem was still there....
2 - at this moment the motor was sent again to bafang and i´m wainting feedback.

 

[borysgo2]

Hello,

I´ve exactly the same issue already at 2 month.... i´ve been in contact directly with bafang sevral times trying find what is the cause.
Firstly was replaced te comunication cable between display and motor (Cable was ok), then the battery was sent to a techinal center to check (battery was OK), after that it was replaced and teted with a new display (display was OK). At the end of those first check´s, Bafang decided to ask me to send the motor to their technical support and the sittuation until now is the following:

1- The motor was sent to Bafang for intervention and supposedly it was replaced the controller. After receive the motor intervened it was tested and the problem was still there....
2 - at this moment the motor was sent again to bafang and i´m wainting feedback.

Yesterday I have swapped new DPC245 display and new button - problem still there. So it looks like problem is in the motor itself. Basically I have swapped everything but the motor controller. Just wondering If I can buy new controller board for M820.

At first problem was random but it was getting worse. Now I can turn ON the bike only one time, than everytymie have to reset the power with BT+BMS.

Interesting thing is --> while I am not able to turn the bike ON , I can plug in BESST interface and it communicates no problem + the display turns ON. (with CAN command send by BESST).

Hcastro​

What battery do You have ?

Regards

 

[Hcastro]

Yesterday I have swapped new DPC245 display and new button - problem still there. So it looks like problem is in the motor itself. Basically I have swapped everything but the motor controller. Just wondering If I can buy new controller board for M820.

At first problem was random but it was getting worse. Now I can turn ON the bike only one time, than everytymie have to reset the power with BT+BMS.

Interesting thing is --> while I am not able to turn the bike ON , I can plug in BESST interface and it communicates no problem + the display turns ON. (with CAN command send by BESST).

Hcastro​

What battery do You have ?

Regards

I´ve a 48V 15A Battery (not from bafang).

About your last coment --> In my case i only can comunicate with Besst tool to the controller when i turn on the bike after unplug the battery cable and plug it again. So, if i try to connect besst tool when the bike doesn´t turn on normally despite the disply turn on (due Besst tool) i can´t read the controller.

 

[aledavi]

Hello.
Could you tell me what display you have on your e-bikes? I've seen this DPC010 and I don't know how it works.
It says it's compatible with the Bafang M820 CAN.
Does anyone have it and can tell me how it works?
Regards.

 

[Hcastro]

Yesterday I have swapped new DPC245 display and new button - problem still there. So it looks like problem is in the motor itself. Basically I have swapped everything but the motor controller. Just wondering If I can buy new controller board for M820.

At first problem was random but it was getting worse. Now I can turn ON the bike only one time, than everytymie have to reset the power with BT+BMS.

Interesting thing is --> while I am not able to turn the bike ON , I can plug in BESST interface and it communicates no problem + the display turns ON. (with CAN command send by BESST).

Hcastro​

What battery do You have ?

Regards

UPDATED SITUATION!

I just receive the motor again from Bafang technical center and unfortunately the ebike still have the same problem... (only turns on after reconecting the battery power cable each time).
Dispite i already test the battery, i will test it again to see if the problem is the BMS system.... at this point i´m completly lost.

 

[borysgo2]

UPDATED SITUATION!

I just receive the motor again from Bafang technical center and unfortunately the ebike still have the same problem... (only turns on after reconecting the battery power cable each time).
Dispite i already test the battery, i will test it again to see if the problem is the BMS system.... at this point i´m completly lost.

What kind of bms is used in yours battery? My one is Jbd.

 

[Hcastro]

What kind of bms is used in yours battery? My one is Jbd.

No idea… I will see tomorrow

 

[temon10]

UPDATED SITUATION!

I just receive the motor again from Bafang technical center and unfortunately the ebike still have the same problem... (only turns on after reconecting the battery power cable each time).
Dispite i already test the battery, i will test it again to see if the problem is the BMS system.... at this point i´m completly lost.

problem is with your battery

 

[Radolf]

I also have the same problem with starting the engine - DIY battery and BMS from JBD 30A. I know another person who also has this problem and also uses BMS from JBD. Fortunately, cutting off the voltage output from BMS for a moment solves the problem once (with the application via Bluetooth).
Maybe one of you has a laboratory power supply and can test if the problem also occurs on it...

 

[Hcastro]

No idea… I will see tomorrow

problem is with your battery

UPDATE SITUATION:

Battery was checked again in a techical center and was OK. I also tested with a new battery and the problem is still the same.
As conclusion, after checking everything twice, the problem must be the motor controller that for some reason when turn off the bike on the display, something in the controller makes a energy discharge in the system. It´s way it need to unplug and plug the battery cable to give the implulse start to the controller.

(the conclusion is my opinion taking into account the several test and feedback from battery technical center).

 

[Waynemarlow]

I‘m guessing a wee bit here but I would say that the M820 is probably starting up the same as the M510’s. If so then it maybe worthwhile looking at the way the the keypad startup simply lowers the voltage level on the signal wire not to ground ( which BESST does to differentiate it from a simple start up signal ) but to a mid voltage level.

Many of the early M510’s had a connector problem on the initial internal connector board which although under test had a connection, it was a high resistance connection, which meant that the keypad voltage level always remained higher than the trigger point ( possibly by only a mere 0.1 volt ) and we couldn’t start the motors. In your case this may well be the case and with a reboot of the motor the voltage is just low enough or the startup routine may well look for another level perhaps and will always default to a motor start.

I found it quite hard with basic voltmeters to accurately test this and in the end simply replaced the connector PCB and associated connector ribbon, since then the occasional No start has disappeared on my M510.

 

[Freda]

I also have this same issue. In my case it was very stupid and probably self-inflicted and I am pretty sure it is a controller issue. I serviced the motor and there was grease on the controller. I removed most part of it with a flat screwdriver, when it touched the controller and gave a short red light. The controller had been disconnected from powersource already long time. I was sure I had shorted the controller since it did not start. After some testing I noticed it starts ones, but after that no more. Need to disconnect battery. Fortunately I also have jbd bms with bluetooth, so I can do it remotely.

I tried all three of my batteries, same for all. One is the extender, which is of course easy to disconnect. I have ordered new controller from aliexpress, it was actually not that expensive. Around 70€ delivered. Aliexpress link

One tip is to put maximum time, 10min, before motor shuts down automatically. So it doesn't stop on short breakes.

 

[borysgo2]

I have ordered the controller anyway. Just wondering what is causing it to fail. Two wires need to be shorted at the display in order to turn the motor on. After that I presume display sends can bus frame to controller to turn On.

If the controller is waken up digitally via can bus there might be a problem with reset generator on pcb, while is stuck high, mcu is off.

 

[Waynemarlow]

I have ordered the controller anyway. Just wondering what is causing it to fail. Two wires need to be shorted at the display in order to turn the motor on. After that I presume display sends can bus frame to controller to turn On.

If the controller is waken up digitally via can bus there might be a problem with reset generator on pcb, while is stuck high, mcu is off.

Are you sure you are not over thinking this ? I would recommend contacting @Dado who has done a lot of research into these motors.

 

[mike_kelly]

I have ordered the controller anyway. Just wondering what is causing it to fail. Two wires need to be shorted at the display in order to turn the motor on. After that I presume display sends can bus frame to controller to turn On.

If the controller is waken up digitally via can bus there might be a problem with reset generator on pcb, while is stuck high, mcu is off.

You should understand that canbus is not like a serial connection. Canbus devices are intelligent. They watch the bus for queries and respond with their info. Wires shorting don't cause things to die. The bus just does not transfer information.

 

[Dado]

I have ordered the controller anyway. Just wondering what is causing it to fail. Two wires need to be shorted at the display in order to turn the motor on. After that I presume display sends can bus frame to controller to turn On.

If the controller is waken up digitally via can bus there might be a problem with reset generator on pcb, while is stuck high, mcu is off.

Bafang CAN motor is not waking up over any CAN bus command. Not possible even to restart or turn off over CAN command. There is one control pin, which you need to ground (over specific resistance) to power on microcontroller. Then controller is running voltage to display (here very bad designed as running full battery voltage to display and high voltage is not a friend with water), display is starting and communicating with controller over CAN.

No need to spread untrue into this mistaken World any more...

 

[Freda]

How hot is too hot? After 3 hour ride, last half hour boost and pushing all the time. 60 degrees Celsius seems like a lot.

I have had this before and haven’t noticed any issues, I am just wondering..