An Electric Scooter Community on a Mission to Stamp out Transportation Mediocrity.

Discuss the Xiaomi mijia mi M365 original and pro versions in this forum. Topics include hardware, software, hacking, riding, and everything in between.
By Ofirk
#14357
:cry: I'm trying to upgrade my scooter range by adding a battery.
I've two m365 batteries.
I tried to connect the two batteries in parallel. but only one battery data cable is connect to the main board.
I used this cable:
https://www.aliexpress.com/item/32997848431.html

But, when I turned the sccooter on the additional battery led turns to red instead of fast flashing.
Any Idea what I'm doing wrong?
Thx
User avatar
By Ben J
#14366
To make it ”work” You need to eliminate BMS of the aux battery or rebuild the entire BMS system to incorporate all cells.
Eliminating any BMS is hazardous. But it will work, until it doesn’t... When that happens, results are smokey.
Obviously, you are in over your head.
Ofirk wrote:
Tue Aug 20, 2019 4:01 pm
:cry: I'm trying to upgrade my scooter range by adding a battery.
I've two m365 batteries.
I tried to connect the two batteries in parallel. but only one battery data cable is connect to the main board.
I used this cable:
https://www.aliexpress.com/item/32997848431.html

But, when I turned the sccooter on the additional battery led turns to red instead of fast flashing.
Any Idea what I'm doing wrong?
Thx
#14373
Don't mind BenJ, He's always kind of a dick, talking down to folks. You can create a junction, either with solder or crimped connectors, for the Yellow/Green/White BMS wires. So that both battery's BMS are connected to the controller. I've had success with this method, and you still have 2 fully functioning BMS controlled batteries. Make sure they're both fully charged before connecting them. Also, since the secondary battery is mounted externally, I'll advise disconnecting the parallel power connection before recharging them separately. This stuff isn't as complex as some folks would like to pretend. Good luck!
Ben J wrote:
Tue Aug 20, 2019 5:29 pm
To make it ”work” You need to eliminate BMS of the aux battery or rebuild the entire BMS system to incorporate all cells.
Eliminating any BMS is hazardous. But it will work, until it doesn’t... When that happens, results are smokey.
Obviously, you are in over your head.
Ofirk wrote:
Tue Aug 20, 2019 4:01 pm
:cry: I'm trying to upgrade my scooter range by adding a battery.
I've two m365 batteries.
I tried to connect the two batteries in parallel. but only one battery data cable is connect to the main board.
I used this cable:
https://www.aliexpress.com/item/32997848431.html

But, when I turned the sccooter on the additional battery led turns to red instead of fast flashing.
Any Idea what I'm doing wrong?
Thx
By Ofirk
#14403
jamiesj410 wrote:
Wed Aug 21, 2019 3:23 am
X2 on both battery’s charged that was really messing with me when I added another battery to my m365 . I used a es4 mounted to the side
Image
So how did you eliminate the original battery from charging the external ones?
By Ofirk
#14404
lurkinglime wrote:
Tue Aug 20, 2019 9:02 pm
Don't mind BenJ, He's always kind of a dick, talking down to folks. You can create a junction, either with solder or crimped connectors, for the Yellow/Green/White BMS wires. So that both battery's BMS are connected to the controller. I've had success with this method, and you still have 2 fully functioning BMS controlled batteries. Make sure they're both fully charged before connecting them. Also, since the secondary battery is mounted externally, I'll advise disconnecting the parallel power connection before recharging them separately. This stuff isn't as complex as some folks would like to pretend. Good luck!
Ben J wrote:
Tue Aug 20, 2019 5:29 pm
To make it ”work” You need to eliminate BMS of the aux battery or rebuild the entire BMS system to incorporate all cells.
Eliminating any BMS is hazardous. But it will work, until it doesn’t... When that happens, results are smokey.
Obviously, you are in over your head.
Ofirk wrote:
Tue Aug 20, 2019 4:01 pm
:cry: I'm trying to upgrade my scooter range by adding a battery.
I've two m365 batteries.
I tried to connect the two batteries in parallel. but only one battery data cable is connect to the main board.
I used this cable:
https://www.aliexpress.com/item/32997848431.html

But, when I turned the sccooter on the additional battery led turns to red instead of fast flashing.
Any Idea what I'm doing wrong?
Thx
I will try to connect in parallel also the data cable. I understood correctly?
Also, when charging, do I need to disconnect also the data cable also or just the power cable that are in parallel?
#14410
Ofirk wrote:
Wed Aug 21, 2019 8:28 am
lurkinglime wrote:
Tue Aug 20, 2019 9:02 pm
Don't mind BenJ, He's always kind of a dick, talking down to folks. You can create a junction, either with solder or crimped connectors, for the Yellow/Green/White BMS wires. So that both battery's BMS are connected to the controller. I've had success with this method, and you still have 2 fully functioning BMS controlled batteries. Make sure they're both fully charged before connecting them. Also, since the secondary battery is mounted externally, I'll advise disconnecting the parallel power connection before recharging them separately. This stuff isn't as complex as some folks would like to pretend. Good luck!
Ben J wrote:
Tue Aug 20, 2019 5:29 pm
To make it ”work” You need to eliminate BMS of the aux battery or rebuild the entire BMS system to incorporate all cells.
Eliminating any BMS is hazardous. But it will work, until it doesn’t... When that happens, results are smokey.
Obviously, you are in over your head.
I will try to connect in parallel also the data cable. I understood correctly?
Also, when charging, do I need to disconnect also the data cable also or just the power cable that are in parallel?
I disconnect everything. Don't know if it is necessary, but my specific installation makes it easy to do. So I figured, why not be cautious?
#14568
hi
There is a very simple method works great very simple and no impact on bms or firmware

Use DPDT switch which middle poles connected to bms. Battery connectd to each end of switch. When one battery runs down flip switch and use other battery.
U have to chage each battery but not a problem. I have two chargers and do at same time.
This was quick overview if u have questions or need diagram let me know.
#14590
Butch456 wrote:
Sat Aug 24, 2019 4:36 pm
hi
There is a very simple method works great very simple and no impact on bms or firmware

Use DPDT switch which middle poles connected to bms. Battery connectd to each end of switch. When one battery runs down flip switch and use other battery.
U have to chage each battery but not a problem. I have two chargers and do at same time.
This was quick overview if u have questions or need diagram let me know.
That is a clean solution, but won't you do better with them wired in parallel. This allows you to avoid, or at least postpone, voltage sag typically experienced with a single battery.
#14599
Hi!

I also want to connect 2 original batteries together.

Will this work connecting only the power cable?
Is the BMS LED flashing red just to let you know it doesn't have a data connection?
Does the second battery provide power despite BMS LED flashing red?

thanks

As this was a rental version whos overstock was […]

Any one got any info on beryl bikes I seen a few[…]

LH/ TF-100 Style Display.

Hi I recently converted a Bird Zero to a personal […]

How do you operate dash without button? I have[…]