I'm curious if you also saw a power increase. The 43v firmware should allow a few more amps vs the 48v firmware
Bafang m820
- Thread starter Vsoria
- Start date
It will work only with DIY battery? Or it should work also with stock one ?
I don't know the upper voltage limit for the 43V firmware (in my case: CRX30PC4313E102001.3 eMTB), but at 54V the system worked correctly (54V because the BMS limited the charging of my battery to 4.15V per cell).
As for the battery voltage when the display shows 20% - I didn't have the opportunity to go that low for 43V firmware, but for 48V firmware: 20% on the display is ~46V of the battery (3.54V per cell). I assume that it will be similar for the firmware 43V, which will give approximately 42.5V for 20% of the battery status according to the display.
To sum up, 43V firmware + 48V battery (13S) will allow operation in the range of ~54V÷42.5V (4.15V÷3.26V per cell).
As indicated by the WATT parameter display for BOOST mode with a fully charged battery:
for firmware 48V (CRX30PC4812E102006.3) maximum I saw 608W
for firmware 43V (CRX30PC4313E102001.3) maximum I saw 620W
And the above values are probably indicated correctly, because at that moment the BMS showed a current consumption of over 11A (for 43V firmware).
I plan to do some more tests and maybe record a video (if I find time) to show the current consumption readings recorded by the BMS and the power readings recorded by Bafang GO on the split Android display (I saw somewhere on YT that this application connects to the DPC245 display).
I assume that it will only work with a DIY battery, but the user of this forum #DADO makes BOXES that, among others, they trick the system into using the full potential of the battery: WWW
I definitely need to test this, I am not so interested in more power, since I use trail or sport mode mostly, but I like to use the whole capacity of the battery.
Report 
So far, the first almost complete discharge of my 48V 13S3P battery (LG M58T) on 43V firmware. During this time, I covered two routes in the mountains and a few kilometers around the house, i.e.:
1. The first route (LINK) with a length of 33km and an elevationof 1000m, mainly in T mode and a little in E (at the end the battery still showed 100% and the voltage on the BMS was 50.36V - but I checked it after 50 minutes, so the battery had time to recover).
2. The second route (LINK) with a length of 29 km and an elevation of 920 m, mainly in S and S+ mode because I had to keep up with the big bikes (at the end the battery showed 23% and the voltage on the BMS was 42.83 V. After 50 minutes I turned on the display which showed 37% and the voltage on the BMS was 43.18 V) - I have no idea on what basis (how?) the % battery capacity is determined, but these were the indications.
If I had ridden the second route alone, it would have been in T mode for sure, and the battery would have discharged less, but the result is still really good - especially since several participants of the second tour discharged their batteries from 100% to 0%
So far, the first almost complete discharge of my 48V 13S3P battery (LG M58T) on 43V firmware. During this time, I covered two routes in the mountains and a few kilometers around the house, i.e.:
1. The first route (LINK) with a length of 33km and an elevationof 1000m, mainly in T mode and a little in E (at the end the battery still showed 100% and the voltage on the BMS was 50.36V - but I checked it after 50 minutes, so the battery had time to recover).
2. The second route (LINK) with a length of 29 km and an elevation of 920 m, mainly in S and S+ mode because I had to keep up with the big bikes (at the end the battery showed 23% and the voltage on the BMS was 42.83 V. After 50 minutes I turned on the display which showed 37% and the voltage on the BMS was 43.18 V) - I have no idea on what basis (how?) the % battery capacity is determined, but these were the indications.
If I had ridden the second route alone, it would have been in T mode for sure, and the battery would have discharged less, but the result is still really good - especially since several participants of the second tour discharged their batteries from 100% to 0%
Last edited:
More or less the same for me with 13S2P (and 48V firmware). in use at minima, the battery down to 43% on the HMI (+- 1400 D+ and 25 km), in T and S (seted at 80%), a few S+ (90 %). After stop, i can read 50%.Report
So far, the first almost complete discharge of my 48V 13S3P battery (LG M58T) on 43V firmware. During this time, I covered two routes in the mountains and a few kilometers around the house, i.e.:
1. The first route (LINK) with a length of 33km and an elevationof 1000m, mainly in T mode and a little in E (at the end the battery still showed 100% and the voltage on the BMS was 50.36V - but I checked it after 50 minutes, so the battery had time to recover).
2. The second route (LINK) with a length of 29 km and an elevation of 920 m, mainly in S and S+ mode because I had to keep up with the big bikes (at the end the battery showed 23% and the voltage on the BMS was 42.83 V. After 50 minutes I turned on the display which showed 37% and the voltage on the BMS was 43.18 V) - I have no idea on what basis (how?) the % battery capacity is determined, but these were the indications.
If I had ridden the second route alone, it would have been in T mode for sure, and the battery would have discharged less, but the result is still really good - especially since several participants of the second tour discharged their batteries from 100% to 0%
Enough for me, i will not play to empties the battery to see what apen
Hi.
Done 1800km service yesterday. Bellow a few pics after I have opened the motor. Spot with the most discolored grease is the biggest metal gear + it's companion. The rest of the motor, gears, bearings etc - looks absolutely spot on.
After a small clean up there is no visible wear on the gears.
Greased all up with PG75, and the next service in about 2000km.
In my opinion if You do the service at about every 1500km - 2000km the motor will last for a long time.
Regards
Done 1800km service yesterday. Bellow a few pics after I have opened the motor. Spot with the most discolored grease is the biggest metal gear + it's companion. The rest of the motor, gears, bearings etc - looks absolutely spot on.
After a small clean up there is no visible wear on the gears.
Greased all up with PG75, and the next service in about 2000km.
In my opinion if You do the service at about every 1500km - 2000km the motor will last for a long time.
Regards
What about noise after service and new grease?
It'd be great if you find some time to write a short post / tutorial how to disassemble, clean, regrease m820.
Noise - I'll find out at the weekend.
To dismantle the motor You need:
1. Remove cir-clip at the drive side.
2. Unscrew 4 bolts.
3. Separate casings slowly about 2mm. Take the sharp knife and separate gasket from the one of casings. Separate casings further 20-30mm and disconnect wires. That is it.
Clean and re-grease:
1. Grab a towel and can of brake cleaner, clean the bits and pieces. You can push out the gear/clutch assembly by hand.
2. Grease it up with Molykote PG75 grease.
3. Remove bearing seals (with sharp knife tip) and clean + re-grease ball bearings (with bearing grease).
4. Clean up rubber seals and apply lightly PG75 grease on them from inside.
5. I greased clutch needle bearing with Shimano RD+ grease.
Assembly:
1. Same as dismantle but in reverse order.
What to be cautiousness about ?
1. Do not over tight the 4 bolts on the casing, just few Nm is fine.
2. Watch out the plastic shields and brackets inside the motor, they are quite fragile, easy to crack.
3. Use proper greases!!.
It looks like bafang has new 36V 417Wh battery, in the same(similar?) form factor, that was previous 360Wh.
old:
new:
According to the information on the website, it is 5mm longer and actually 20mm narrower. I would be surprised, if it is actually 20mm narrower, considering it has the same number and type of cells.
If they would also update 43V 410Wh battery, that would be 475Wh. But I have a feeling that bafang is abandoning 43V system. On M820 page, only 36V and 48V versions are listed. They were selling 43V 410Wh as MTB, but they might start selling this new 36V 417Wh as MTB and 360Wh as road version.
This is just my speculation, though.
old:
According to the information on the website, it is 5mm longer and actually 20mm narrower. I would be surprised, if it is actually 20mm narrower, considering it has the same number and type of cells.
If they would also update 43V 410Wh battery, that would be 475Wh. But I have a feeling that bafang is abandoning 43V system. On M820 page, only 36V and 48V versions are listed. They were selling 43V 410Wh as MTB, but they might start selling this new 36V 417Wh as MTB and 360Wh as road version.
This is just my speculation, though.
Thanks to sharing your experience.
Where have you seen (or how you determine) that Shimano RD+ grease is necessary for clutch needle bearing ?
JimLee-Lightcarbon
Lightcarbon
the two 36V battery are the same battery box, only chang the rated capacity from 5ah to 5.8ah, so the inner size have a little change. the size of 417 battery is wrong in their web, I told to them and they said will change it,It looks like bafang has new 36V 417Wh battery, in the same(similar?) form factor, that was previous 360Wh.
old:
new:
According to the information on the website, it is 5mm longer and actually 20mm narrower. I would be surprised, if it is actually 20mm narrower, considering it has the same number and type of cells.
If they would also update 43V 410Wh battery, that would be 475Wh. But I have a feeling that bafang is abandoning 43V system. On M820 page, only 36V and 48V versions are listed. They were selling 43V 410Wh as MTB, but they might start selling this new 36V 417Wh as MTB and 360Wh as road version.
This is just my speculation, though.
temon10
Well-known member
any company producing this battery case, so we can make DIY battery for your frame. or maybe your company can make it.
JimLee-Lightcarbon
Lightcarbon
This is Bafang's proprietary mold. Maybe it can be 3D printed?
In addition, I confirmed with Bafang's technicians that they have 417wh batteries, but the sales department said they have not yet started supplying them, so next, we still recommend 43V 410wh batteries until 417wh batteries are available in large quantities.
May i ask what grease is PG75? Brand?
Molykote PG75.
Thanks
Had a few KM's done since the service was done. The motor noise when pedaling is about the same. The only difference is a bit less rattle when going down the trail. I think this is a result of greasing up one way clutch (which was nearly dry before). I have used shimano shadow rd+ grease, the same as for the derailleur clutch.
temon10
Well-known member
any other grease beside molykote? it's hard to find here in Indonesia.
Yes.
Check input voltage and dismantle motor if neaded
Charge your battery
I had charged it up fully, the night before it stopped working.
43V battery should be 49,2V fully charged
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