Building a 20s21p battery pack out of LG MJ1 18650 cells

Batteries, Chargers, and Battery Management Systems.
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KryceS   1 µW

1 µW
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Joined: Dec 07 2020 4:36pm

Building a 20s21p battery pack out of LG MJ1 18650 cells

Post by KryceS » Feb 05 2021 9:10am

Hello,

My name is Chris, from France, I’m new on this forum and in the world of Ebikes.

I actually using a converted DH bike (BSSHD, Phaserunner, CA, and 2 EM3eV batteries in 50V) on my daily uses, essentially to go to work (84 km round trip at 46-50 km/h of speed and 1500W). I love this bike! And I don’t really play with the settings of both Phaserunner and CA.

I have for a long time now, a big project for me, build an E-Bike with a enduro frame. I already order everything that I need. It will be a QS V3 205 5000W motor with a Sabvoton 72150.
I received the cells, the spot welder, the nickel strips and etc... I will put the battery in a hard case and then in the frame itself.

But the building of batteries is very new for me. And I looking for some advices and tips.
I plan, like Mike from Electric bike school (https://youtu.be/YwyQohkELEU), to build it in two pieces that fold on top of each other. So the first part will be a 20s11p and the second one a 20s10p. All with a smart 300A BMS.
I saw that he connect the two part with nickel strip on one end and some wires on the other end. With type (AWG) should I use. I understand that the parallel connections don’t carry a lot of current, but I’m not sure witch one I must use.

Next interrogation is the nickel strips for the serial connections. I use 7mm x 0.2 mm nickel strip, I understand that they can carry 5 A nominal.
So if I don’t stack up the strips, my entire serial connection can carry 21x5 A = 105 A. If I stack up two nickel strip, my pack will be capable of carrying 210A that’s 60A more than my controller can handle (150A). I’am right ?

Thank you.
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