BMS Reset

James e160

Member
Jul 2, 2021
13
0
United kingdom
Hello guys,



My bike was playing up and I think the battery shorted out as water got in the connector from the motor and now it won't power on. I've opened the battery up and tested the cells with a multimeter and it's reading 45.6v on the cells (its a 46v battery and was fully charged). Also I've checked the fuse and that seems fine too, so now I'm trying to reset the BMS internally, I have attached a picture and I'm just making sure the bit I've circled in blue is the bms connecter I need to be unplugging and plugging it back in when charging. Just dont want to be electrocuted so I thought I'd check. Any help is appreciated thanks 

20221221_110134.jpg
 

Planemo

E*POWAH Elite
Mar 12, 2021
605
706
Essex UK
I presume its reading 0v on the main out?

That does look like a BMS connector but I would expect there to be more than 5 balance leads...do you know the battery config?
 

James e160

Member
Jul 2, 2021
13
0
United kingdom
I presume its reading 0v on the main out?





That does look like a BMS connector but I would expect there to be more than 5 balance leads...do you know the battery config?


Yeah it's reading 0v on the main out, unfortunately I don't know the config no although I could try find it
 

Planemo

E*POWAH Elite
Mar 12, 2021
605
706
Essex UK
Who makes the battery?

If it were mine I would unplug it anyway. It'd be high hopes in resetting the BMS but you don't have much to lose. I'd probably do the left plug too (charge + and -)

Looking at the soldered parallel tabs it looks like you may have at least 8 or 9 strings. If unplugging stuff doesn't work I'd be unsoldering all the tabs and checking the other side of the board too. I would also check the voltage of each string - you may have 45.6v total but that doesn't mean one string isn't way too high and another too low (either could be enough to not want the BMS to play ball).
 

James e160

Member
Jul 2, 2021
13
0
United kingdom
I was just a bit worried unplugging it and then plugging it back in after the charger is plugged into the mains, from previous experience I learnt not to mess with stuff when it's plugged in to the mains lol
 

S13

Active member
Mar 1, 2021
237
144
NL
What do you mean by "bms connector"?
The whole thing IS the BMS and it has lots of connectors:

- Charge port (C+, C- / but could be something else, just follow where the leads go)
- Motor controller communication (seems to be the one you circled in blue, cant read text for that reason)
- Primary output contacts (P+, P-)
- HMI interface connector (P703)
- Battery cell contacts (G, V1..V9, VP)

Your lucky, everything is written on the silkscreen ;)
 

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