Bafang M820 Firmware thread
- Thread starter Zimmerframe
- Start date
Yes I did, I believe it is maximum. Since this picture I did rebuild it so I now have plastic M6 screws and metal counterpart on battery. Also added a handle to pull it out, since I made it very tight so everything would stay in place. So far has been working very well.
I would make a 13S2P shorter using the second holes for attaching it, it would be about 14-15 cm shorter.
PaulH
Member
Very nice job Freda, Bafang should hire you as a consultant or something.
Thank you, but I am only a happy amateur, trying to get the best out of what I have.
temon10
Well-known member
DId U make 3D printing for this battery holder?
For the present 21700 cells I used this, M6 size. I glued and taped the aluminum square nut in place on the battery. And plastic M6 screws. I have cellofoam around the cells to make it a tight fit. It doesn't move at all, even without the screws. That is why I needed a handle to pull it out.
For a 18650 cell battery, normal brackets fit in the frame: Bracket
as per the good old custom, the bafang firmware is a disaster in terms of battery percentage. I went to check the battery voltage when it was 20%. voltage is 36V. horror, with the firmware I use and a 10s battery, the range is 30km and 1500m altitude. battery is 10s 21700 cells LG58t, 17.4ah. below 70% the percentage drops rapidly in percentages of 5-10%. it doesn't show on the screen that it drops by 1%, well done Bafang!
voigtkampff
Active member
I have a similar effect. It seems like the controller is unable to take battery level measurements as long as I'm pedaling uphill and engine is running. During the ascent battery level stays constant, only after I stop pedaling I see a sudden battery percentage drop by 5-10%. Is this the same with you?
the same thing happens to me!
the firmware is like that!
on the m500, m510 and m820, program the firmware to reduce the power to 30%. What do they protect with that voltage?
according to the man who works the batteries for me, they protect the controller-motor because if the voltage is too low, the components heat up more.
it is not clear to me that it shows 20% at 36V! 36V is the nominal voltage of the battery, my battery is 17.4A 625wh, according to the bafang firmware the battery is approx. 400wh!
Normally batteries work from 30v to 42v. at 30v turns off bms. that means it works between approx. 32v and 42v. the bafang firmware probably works between 34-35v and 42v.
where a lot of battery capacity is lost.
I haven't measured voltage, but it feels that percentage drops quickly down to 90, then slowly to 60-70 and after that big drops down to 20%. Under 20% seems to last forever, but that can be thanks to very low assistance.
Waynemarlow
E*POWAH Elite
The last couple of volts only equates to about 10% of the total Wh available. Bafang obviously don’t want to stress their batteries life span by going down to completely emptying the cells. It makes good commercial sense when a large percentage of their clients are commuters rather than a few EMtbers.
In my view to get that last 10% then the options are pretty limited. About the only option we have is the BB Racing device BB Racing – K1 eBikes – Bafang Tuning and Services, it seems to work well and will allow 52 volt batteries to be used.
Hello. what bms are you using in the batteries?
temon10
Well-known member
cheap 10s bms from aliexpress
salvaparraes
Member
Hola, tengo instalada la versión CRX30PC3615E102003 3_eMTB_besst_230308 en mi M820, pero en la última actualización de Bafang go+, V 3.0.0: no cambia los parámetros de asistencia, sin embargo antes en la versión anterior si cambió los parámetros de asistencia, me lo pueden confirmar qué versión tienen para que el soporte pueda cambiar. Gracias.
voigtkampff
Active member
Maybe you could ask Linda if she can share Release Notes for this firmware as well? Would be interesting to know what was changed in this version. If only Bagang publishes this data...
That was first what i asked her... unfortunately they don't get any changelog form Bafang.
But now we see how they code filenames:
CRX30PC4812E102012.1_240412
CRX30PC - model / type ?
48 - V
12 - A
E10 - ?
2012.1 - compilation
240412 - date (YMD)
After updating this FW, when i'm checking online FW update in BESST PRO, there is no new update. Correct me if i wrong, but there was prompt about possible update before, right ?
voigtkampff
Active member
Yup, there was upgrade prompt. With the caveats that the version check relied on engine SN, which in our case led to downloading 36V FW version instead of 48V. Anyway, IDK if Bafang even officially releases 48V FW for M820 or if this is hacked by rewriting some registers with values for 48V in the 36V release.
nice, new 43v firmware!
It’s the road version, not mtb. Not sure how it impacts the behavior
DiReCtX
Member
Hi
on the eroad firmware (CRX30PC3615E102002.5_eRoad_230721) I had no assistance when climbing at a large angle, on a smaller one and on flat terrain it was ok. On the emtb firmware (CRX30PC3615E102003 3_eMTB_besst_230308) there is no such problem and the engine provides assistance for about a second after finishing pedaling
DiReCtX
Member
Although it seems to me that this time depends on how hard I pressed the crank, the harder I press the longer the time, when I ride calmly (I use less force) the support time is definitely shorter
There seems to be three 43V firmwares available here. Two of them are the same with different file names and the third is a eroad version. I have now tried all of them and they all have very long overrun, like a second at least. With the 48V version I did not have this and they seemed smoother otherwise as well.
These are available already:
CRX30PC4313E102004.3_eRoad_230317
CRX30PC4313E102001 3_eMTB_230317
So do anyone have a newer/better verison of 43V firmware? It would be highly appreciated.
These are available already:
CRX30PC4313E102004.3_eRoad_230317
CRX30PC4313E102001 3_eMTB_230317
So do anyone have a newer/better verison of 43V firmware? It would be highly appreciated.
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Did you notice that you got better range with a 48v battery running 43v firmware since it doesnt cut out as early?
Still haven't had the time to try, I will update on this later.
