Bafang m820

Waynemarlow

E*POWAH Master
Dec 6, 2019
1,108
889
Bucks
I will store/charge it in warm garage, so initially it will be ok, maybe just better to skip the really cold days.
If you have already purchased the batteries then there is only one way to find out whether the cold will have an adverse effect, go ride.

My guess would be that if you are starting from a warm battery then you should be fine. The only real issue will be is when you stop off for a long lunch and coffee and leave the bike outside.

There's quite a number of neoprene thermal covers you can buy for Ebikes, it maybe worth investing in one.

1697188754835.png
 

brbr

Active member
Dec 28, 2022
529
270
France
If you have already purchased the batteries then there is only one way to find out whether the cold will have an adverse effect, go ride.

My guess would be that if you are starting from a warm battery then you should be fine. The only real issue will be is when you stop off for a long lunch and coffee and leave the bike outside.

There's quite a number of neoprene thermal covers you can buy for Ebikes, it maybe worth investing in one.

View attachment 126697
I was trying to understand what is the worst thing that could happen ?
The cells will heat because you're draining more than they can deliver, by heating, they will deliver more power and stabilise ? that's it ? I don't see any risks here but I'm far from being an expert :)
 

Waynemarlow

E*POWAH Master
Dec 6, 2019
1,108
889
Bucks
Most manufacturers recommend not to stress the cells too much when they are very cold, it can shorten their max charging life somewhat. But then we probably will not ever do more than the 5 - 10 K of cycles they recommend as full expected lifespan, so does it really matter if we do shorten the cell life a small tad ?

One of the guys I ride with has just done 2500 miles on his Rail, typically only doing 25miles a charge in all weathers including some below zero night temps. Thats only 100 charges. His battery is down to 95% full charge, so its still going strong.
 
Hi @brbr, if you're interested in charging best practices and battery care in general, take a look at this other thread:
 

borysgo2

Active member
Feb 1, 2023
121
196
Ireland
Hi
I am in process of assembly of lce930 with m820 motor.
I have ordered 43V motor and the battery kit.

Is my firmware 36 V version ??

Another issue I have, battery level indicator stays at 36% after a few hours of charge.
The charger green LED stays ON solid when I putt the plug into the charging port, have anyone had same issue ?

Thanks

my firmware.jpg
 

brbr

Active member
Dec 28, 2022
529
270
France
Hi
I am in process of assembly of lce930 with m820 motor.
I have ordered 43V motor and the battery kit.

Is my firmware 36 V version ??

Another issue I have, battery level indicator stays at 36% after a few hours of charge.
The charger green LED stays ON solid when I putt the plug into the charging port, have anyone had same issue ?

Thanks

View attachment 126725
Yes it looks like a 36v controller.
You have the besst tool, the change is easy
 

borysgo2

Active member
Feb 1, 2023
121
196
Ireland
OK have a firmware. Just instruction is not clear.
Can I update firmware via interface connected into the HMI display or have to remove motor and plug it directly to the motor itself ??
 

brbr

Active member
Dec 28, 2022
529
270
France
OK have a firmware. Just instruction is not clear.
Can I update firmware via interface connected into the HMI display or have to remove motor and plug it directly to the motor itself ??
Just plug it normally instead of the display
 

brbr

Active member
Dec 28, 2022
529
270
France
I’m driving right now so i don’t have nor the pc nor the besst tool but I think therés an update menu?
 

borysgo2

Active member
Feb 1, 2023
121
196
Ireland
M820 --> light output 12V 500mA, question there, is the output constant current type (like LED driver) or rather constant voltage 12V with 500mA over current protection (power off when protection is active) ?

Thanks
 

clix

Active member
Jul 24, 2022
186
207
EU
M820 --> light output 12V 500mA, question there, is the output constant current type (like LED driver) or rather constant voltage 12V with 500mA over current protection (power off when protection is active) ?

Thanks
Second one. Output is constant 12V, with the overcurrent protection. But, to me, this overcurrent protection looks rather wierd.
I have a light with cca 380mA at 12V. If I have the light connected, while I turn it on with the HMI, it triggers overcurrent protection and ligth is just blinking. But, If I turn it on in HMI, and connect it later, it works. To me, it looks like inrush current to my light is triggering OC protection, but the protection is active only right after the turn on.
I solved this issue, with the 0.5 Ohm resistor in series to the lamp, to lower the inrush current. Now it works as expected.
 

brbr

Active member
Dec 28, 2022
529
270
France
M820 --> light output 12V 500mA, question there, is the output constant current type (like LED driver) or rather constant voltage 12V with 500mA over current protection (power off when protection is active) ?

Thanks
On my side I used a dc dc converter pluged on the main battery. My light was too powerful for the default light output.
I think I will use the integrated light connector for the rear light
 

Dado

Active member
Jun 28, 2022
692
463
Bratislava
Best from main battery, also have it over dc/dc.
Cars are mad of me. ;) 25W Led light, it is strong as sh... Was surprised I feel heat on my skin when pointing on me.
 

brbr

Active member
Dec 28, 2022
529
270
France
Best from main battery, also have it over dc/dc.
Cars are mad of me. ;) 25W Led light, it is strong as sh... Was surprised I feel heat on my skin when pointing on me.
I only have 2000 lumen! In complete darkness in the forest it was a bit scary 😃
I now use a 3500 lumen on my helmet in addition, I ran into a runner in the woods, I think he didn’t recover fully his vision yet 😂
 

Dado

Active member
Jun 28, 2022
692
463
Bratislava
He could have also think aliens came down. ;) Same experience.
Mine is labeled as 5000lm, but it can have cca 2500.
 

borysgo2

Active member
Feb 1, 2023
121
196
Ireland
Hi. Got a bit of the problem with charging of Btf014 battery. At the moment it is 59% left @ 45V, when I plug the charger in, it does not go red(charging), lights up solid green instead (like fully charged). There is no faults in diagnostics. Just wondering if there is a voltage threshold that battery can not be topped up when over 50%?
 

brbr

Active member
Dec 28, 2022
529
270
France
Hi. Got a bit of the problem with charging of Btf014 battery. At the moment it is 59% left @ 45V, when I plug the charger in, it does not go red(charging), lights up solid green instead (like fully charged). There is no faults in diagnostics. Just wondering if there is a voltage threshold that battery can not be topped up when over 50%?
I’ve seen that the charger sometimes is plugged but does not charge, you have to plug it again or turn it in order to have a good contact, maybe that’s the issue
 

mike_kelly

Well-known member
Subscriber
Aug 11, 2022
941
774
US
Hi. Got a bit of the problem with charging of Btf014 battery. At the moment it is 59% left @ 45V, when I plug the charger in, it does not go red(charging), lights up solid green instead (like fully charged). There is no faults in diagnostics. Just wondering if there is a voltage threshold that battery can not be topped up when over 50%?
If the battery charger was not for the right voltage, say 36v, it would charge until it reached 36v and shutoff.
 

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