What BMS for 21700 cells?

kevhef

1 µW
Joined
Sep 26, 2022
Messages
2
I am planning a battery build ...14s 5p using Samsung 40T cells. (21700 @ 4000 mAh)
The cells have a rated nominal voltage of 3.6 ...so a 14s pack runs 50.4 volts.
The controller for my hub motor is rated for 25A continuous.
I am unsure as to what BMS to use... Can anyone please advise?

A related concern is how to properly charge this battery...
 
A 30A BMS should suffice, take your pick all the way up to Bluetooth enabled.

But don't take offense but if you don't have the knowledge of what BMS to use and how to hook up a charge plug to it then perhaps you would want to be very extra careful about building a battery to begin with?
 
kevhef said:
I am planning a battery build ...14s 5p using Samsung 40T cells. (21700 @ 4000 mAh)
The cells have a rated nominal voltage of 3.6 ...so a 14s pack runs 50.4 volts.
The controller for my hub motor is rated for 25A continuous.
I am unsure as to what BMS to use... Can anyone please advise?

A related concern is how to properly charge this battery...

I have 16s6p Samsung 40T battery with 120A continous Daly BMS.
Suitable BMS for your battery is Li-ion 14s and >25A upto 100A continous. Size also depends how the battery is built, what you prefer (future need?), space available etc.
I would suggest 50A(120A Peak) BMS and battery build to support that if no other info available.
 
Thank you Bigwheel, TuomasK, and ebuilder.

...Bigwheel... I am and will continue to exercise "extra caution"... Yes, I'm a DIYer, but I believe in thoroughly researching and educating myself before undertaking a thing... that's why I'm here asking questions :thumb: ...and no offense taken... if I was too proud to accept a cautionary comment, then I would be in a hurry to injure myself and maybe someone else.

...ebuilder... I like the logic... I am reconsidering the build to use 50E cells... however, after doing a brief search for 14S 50v 30A BMS with max current 50A I am unable to find a candidate... planning to use 1/8" pvc sheet for enclosure...

https://www.usplastic.com/catalog/item.aspx?itemid=137301&v1=&v7=&gclid=CjwKCAjwvsqZBhAlEiwAqAHElYDcUcJ6FHAUfD5ncnEuouimRJeXwd0skiduTiZ98aSxFuh1T7mFARoCJfIQAvD_BwE

...TuomaK... current plan includes most efficient use of the bikes frame space... no plans to use the battery for anything other than this build... thank you for your input
 
14S is often referred to as 52V (14x3.7) and fully charged is 58.8V. there should be many BMS available, I use the neptune 15 as I like the power on/off switch, bluetooth monitor and speed sensor.

for a charger the Meanwell sealed LED drivers power supplies are awesome
 
kevhef said:
... however, after doing a brief search for 14S 50v 30A BMS with max current 50A I am unable to find a candidate...

Try https://srikobatteries.com/ he has been able to provide any Daly BMS that I have looked for.
 
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