Bafang M820 Firmware thread

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Limited to 6kph in the settings sadly. All the code is there if we knew a programmer ;)
 
Waynemarlow said:
Not so sure about the max current as I‘m lead to believe that it’s hard coded. I have changed mine here but I suspect that although it seems the current has changed, I think it maybe only altering the max torque look up table and giving only a momentary gain.

The good thing is the motor seems very tuneable, but only within some weird constraints that includes speed of all things. I already have mine tuned in Boost to an almost Bosch like feel, but those settings have repercussions elsewhere in the lower assist levels, working on it.
Click to expand...

I think you're mistaken. Most of the parameters are hardcoded. You can change them from the program, but they don’t have any effect. That’s the case with parameters bit 0–40 from bank 6012 that you mentioned. The only exception is bit 36, which I don’t know what it does because it’s not documented. The next set of bits that can be set and to which the motor actually responds are bits 40–57 from bank 6011.
 
Hi Everyone a few months back I bought a Cef50 emtb m820 with 36v 720wh battery , unfortunately they supplied it with road bike firmware. I then had to buy a besst tool and Jean gave me this firmware
CRX30PC3615E102010.1_2306
29-1.bin
It has more power but seems to have lots of overrun and top speed has dropped to 25kph max.
Wondering if there's a better firmware to use
Thanks
 
Jocamara said:
Hi Everyone a few months back I bought a Cef50 emtb m820 with 36v 720wh battery , unfortunately they supplied it with road bike firmware. I then had to buy a besst tool and Jean gave me this firmware
CRX30PC3615E102010.1_2306
29-1.bin
It has more power but seems to have lots of overrun and top speed has dropped to 25kph max.
Wondering if there's a better firmware to use
Thanks
Click to expand...
Hi try this one to see if it suits you, it's the best for me to climb mountains
Can you share the file
CRX30PC3615E102010.1_230629-1.bin because I haven't seen one like this for 36V anywhere, I'll compare it with other firmwares

other firmware for 36V
 

Attachments

Jocamara said:
Hi Everyone a few months back I bought a Cef50 emtb m820 with 36v 720wh battery , unfortunately they supplied it with road bike firmware. I then had to buy a besst tool and Jean gave me this firmware
CRX30PC3615E102010.1_2306
29-1.bin
It has more power but seems to have lots of overrun and top speed has dropped to 25kph max.
Wondering if there's a better firmware to use
Thanks
Click to expand...
"And for me best version is 2.5 - more effort is required to get top power witch leeds to better battery efficency, also no overrun here. But it shloud support more on high cadence."
I agree with user mdi
 
maglo18 said:
I think you're mistaken. Most of the parameters are hardcoded. You can change them from the program, but they don’t have any effect. That’s the case with parameters bit 0–40 from bank 6012 that you mentioned. The only exception is bit 36, which I don’t know what it does because it’s not documented. The next set of bits that can be set and to which the motor actually responds are bits 40–57 from bank 6011.
Click to expand...
I agree, it would be more than likely to be hardcoded to a read only register. As per the Amps command, I ran three full power tests logging the max A’s at the battery at the factory setting of 12A, changed that to 14A’s within the program and repeated that same 3 power runs logging the Amps. It remained at or around the max 11.93 A’s. I confirmed that in my previous statement that the Amps was hardcoded.

I’m not so sure though about the torque sensor codes. For anyone interested simply rewrite the min max levels to 1 and 2 on 4 of the 5 Spd levels and then go ride your bike. Let us know the outcome. If the program is unable to change the fields you have lost nothing, if it can change the fields you should feel major response changes to the way the motor operates. Should take less than 10 minutes to change the fields and about 5 minutes of riding your bike.
 
There is also Canable tool:
github.com

GitHub - bart594/bafang_canable_pro: Bafang Besst software replacement for M500, M510, M560 etc

Bafang Besst software replacement for M500, M510, M560 etc - bart594/bafang_canable_pro
github.com github.com
1752239151506.png

Someone test this with M820 ?
 
Best looking and probably the most comprehensive but won't work with the BESST interface, only with CAN sniffers and you need a computer degree to get it running in Windows :) . It probably will in time be OK but not just yet to those with the BESST tool.

You obviously have it running, does it have anywhere to access say in the sensors tab, the full motor parameters such as speed ?
 
Last edited:
Looks good if it will show actual assist and ramp up curves. I think you can tap into the Can wires at the battery or speed sensor additionally but don’t hold me to that.
 
Jocamara said:
Hi Everyone a few months back I bought a Cef50 emtb m820 with 36v 720wh battery , unfortunately they supplied it with road bike firmware. I then had to buy a besst tool and Jean gave me this firmware
CRX30PC3615E102010.1_2306
29-1.bin
It has more power but seems to have lots of overrun and top speed has dropped to 25kph max.
Wondering if there's a better firmware to use
Thanks
Click to expand...

To change the speed LIMIT , Besst PRO can NOT help you. You need to use BESST SETUP ONLY. Download here

github.com

Bafang_M500_M600/BESST/dist at main · OpenSourceEBike/Bafang_M500_M600

Contribute to OpenSourceEBike/Bafang_M500_M600 development by creating an account on GitHub.
github.com github.com

or read Here

Bafang M820 Speed Limit

Hey all, I usually don't resort to forums for my technical questions, but I'm having trouble finding my answer. Looks like my motor is speed limited to 16mph. I'm in the US and we are limited to 20mph and I'd like to correct that. Am I correct in thinking I need BESST Tool for that? Or can this...
www.emtbforums.com www.emtbforums.com
 
I tested bart Canable tool with m820 today and unfortunately Assit tab is not working (only Startup angle can be changed).
Also checked:
walk speed assit - no effect it's still max 2.5km/h..., initial value was 0 so it's no wonder
limp mode - set to 5%, not tested but initial value was at 25%, if i remember correctly is should be 20% so no hopes for that

Maybe i will test it with more recent firmware.
 
Fitted one of Dado’s devices to check on temperature, sadly the motor is not reporting correctly the temperature, not sure it’s the motor or all M820 motors.

I’ve been playing with various settings using the BESST tool and AndreyPr’s free firmware with good success. Almost a very rideable motor now compared to the base Bafang settings.
 
Waynemarlow said:
Fitted one of Dado’s devices to check on temperature, sadly the motor is not reporting correctly the temperature, not sure it’s the motor or all M820 motors.

I’ve been playing with various settings using the BESST tool and AndreyPr’s free firmware with good success. Almost a very rideable motor now compared to the base Bafang settings.
Click to expand...
Please share this AndreyPr's firmware.
 
Waynemarlow said:
Fitted one of Dado’s devices to check on temperature, sadly the motor is not reporting correctly the temperature, not sure it’s the motor or all M820 motors.

I’ve been playing with various settings using the BESST tool and AndreyPr’s free firmware with good success. Almost a very rideable motor now compared to the base Bafang settings.
Click to expand...
If I may ask, I would also test it and what voltage is 36V?
Thank you
 
parnel bosch gen4 said:
Please share this AndreyPr's firmware.
Click to expand...
Sorry firmware should have read software.

Just be a bit aware making changes on the software Spd Tabs are not quite clear cut in how they affect the motor eg by changing the max speed on the motor also changes the motor responses. Weird in some ways but by changing numbers 1 column at a time, I’m getting to understand more.

Some running 36 Volt firmwares are reporting they cannot change the response at all, I’m running 48 volt firmware is there something there we need to know more.

Having changed mine I no longer have what I thought was over heating problems and the motor cutting back the Watts, definitely just me running out of pressure on the pedals at higher cadences on longer climbs.
 
I compared spd table in two firmwares 36V2.5 and 36V3.2.
I ride both of them and know that 3.2 is more sensitive torque which spd table should show.
But spd table is the same for both:

JSON: 
 "torque_profiles": [
    {
      "start_torque_value": 20,
      "max_torque_value": 40,
      "return_torque_value": 12,
      "min_current": 10,
      "max_current": 100,
      "torque_decay_time": 3,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    },
    {
      "start_torque_value": 10,
      "max_torque_value": 40,
      "return_torque_value": 9,
      "min_current": 12,
      "max_current": 100,
      "torque_decay_time": 6,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    },
    {
      "start_torque_value": 7,
      "max_torque_value": 40,
      "return_torque_value": 6,
      "min_current": 15,
      "max_current": 100,
      "torque_decay_time": 6,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    },
    {
      "start_torque_value": 6,
      "max_torque_value": 35,
      "return_torque_value": 5,
      "min_current": 15,
      "max_current": 94,
      "torque_decay_time": 6,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    },
    {
      "start_torque_value": 5,
      "max_torque_value": 30,
      "return_torque_value": 4,
      "min_current": 12,
      "max_current": 88,
      "torque_decay_time": 5,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    },
    {
      "start_torque_value": 5,
      "max_torque_value": 25,
      "return_torque_value": 4,
      "min_current": 10,
      "max_current": 83,
      "torque_decay_time": 5,
      "start_pulse": 1,
      "current_decay_time": 200,
      "stop_delay": 250
    }
  ],
 
@mdi this is perhaps taking the thread perhaps too far down the experimental route than most would come here looking for firmware specific information. Can I suggest we move the experimental part across to Bafang M820 thread where there are others way more experienced than I in these matters and where we can perhaps learn more in the process.
 
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I tested this 36V 10.1 firmware today, it's to sensitive for me, very similar to 3.3/3.2.

Whats interesting about it, that it have diffrent default spd table setup:
1753722796723.png


I'm sharing the file if someone wants to try it.
 

Attachments

Interesting values in the min current, I can see why it is a bit feisty if my theories are correct.

Have you tried to reprogram that version of firmware ? Would be interesting to know if we can alter these values ?
 
Yes I tried. I do not feel any effect. Even with very stupid values like 10% max current every where. Same as other 36V firmwares.
 
Yes I get the same on the 48V firmwares if I reduce max currents to very low values.

I think the Assist levels set in the Assist tab seems to take priority over those sped tabs. I suspect also you are running 25kph max speeds ? If so then any changes will be condensed into very short bands of cadence levels and speed combined.

@mdi Out of curiosity what cadence rpm to you normally use ?
 
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