bms in series

[altermontrealiste]

Hi ; searching for links to know how to plug 2 https://bmsbattery.com/bmspcm/330-s...es-bms-pcm.html#/212-discharge_current-20_40a in series for a 18s and 20s setups (would do up to 26s). I know I saw a page about it but search didnt show it to me.

Actually, I have no need for charge max A or discharge max A (40Ah chevy volt batteries with 10Ah charger and 500w e-bike) ; I just want to ballance my cells and report to arduino for display....

Thanks

 

[friendly1uk]

Output fets will need to be able to handle full pack voltage and the charging control from both chips bought together with opto isolators to kill a common bulk charger.

I reckon that's about it


edit: your comms might also require opto isolation. The neg of one board is half a pack away from the neg on the other. etc etc

 

[teklektik]

Hi ; searching for links to know how to plug 2 https://bmsbattery.com/bmspcm/330-s...es-bms-pcm.html#/212-discharge_current-20_40a in series for a 18s and 20s setups (would do up to 26s). I know I saw a page about it but search didnt show it to me.
...
(40Ah chevy volt batteries with 10Ah charger [sic] and 500w e-bike)

If you want to use a single charger instead of two isolated chargers you will need a 2-wire BMS as discussed here.

Also - those BMSes are 5A which would not handle the current from your 10A chargers. Here's a bunch of other Bestech 10s choices that might fill the bill.

If you only want balancing, you could look at balance boards (see Bestech Power).

 

[altermontrealiste]

Output fets will need to be able to handle full pack voltage and the charging control from both chips bought together with opto isolators to kill a common bulk charger.

I reckon that's about it


edit: your comms might also require opto isolation. The neg of one board is half a pack away from the neg on the other. etc etc

thanks for the info ; modding a fet can be done... have you done it yourself?

 

[altermontrealiste]

Hi ; searching for links to know how to plug 2 https://bmsbattery.com/bmspcm/330-s...es-bms-pcm.html#/212-discharge_current-20_40a in series for a 18s and 20s setups (would do up to 26s). I know I saw a page about it but search didnt show it to me.
...
(40Ah chevy volt batteries with 10Ah charger [sic] and 500w e-bike)

If you want to use a single charger instead of two isolated chargers you will need a 2-wire BMS as discussed here.

Also - those BMSes are 5A which would not handle the current from your 10A chargers. Here's a bunch of other Bestech 10s choices that might fill the bill.

If you only want balancing, you could look at balance boards (see Bestech Power).

the thing with those bms is that the ox890 chip can be interfaced with arduino easily, and, with the ballancing feature, it's the main thing i want for my monitoring system. bestech ballancers are nice, but I also want to have some data displayed on a lcd, or even create a new pcb using those chips

 

[friendly1uk]

Output fets will need to be able to handle full pack voltage and the charging control from both chips bought together with opto isolators to kill a common bulk charger.

I reckon that's about it


edit: your comms might also require opto isolation. The neg of one board is half a pack away from the neg on the other. etc etc

thanks for the info ; modding a fet can be done... have you done it yourself?

I have not needed to, but there are threads that revolve around pre-charge and electronic contactors that list many ways of doing it without turning to industrial semiconductors. You could swap out the fets on the boards, or use the boards to control an external bank of fets talked about elsewhere.

It should be very straight forward. 26S huge power programmable $60 but I have never needed it.

 

[friendly1uk]

I have put an half an hour to show how it might be done on another thread, using the chip you talk of
https://endless-sphere.com/forums/viewtopic.php?f=14&t=20971

 

[altermontrealiste]

I have put an half an hour to show how it might be done on another thread, using the chip you talk of
https://endless-sphere.com/forums/viewtopic.php?f=14&t=20971

Thanks a lot for the link ; I will read and contribute on that thread instead