My first DIY 18650 battery pack

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Hello all. I'm working in my first ebike and my first battery pack.

This is a 16s 8p 18650 panasonic 2900 mAh. Total 23.2 Ah and 67.2 Volts.

Here I explain how I built it:

My old freeride bike (15 years?)



You can see that it has a reinforcement in the center of the frame. This is a complication and forces me to split the battery pack in two (and put the BMS out of the pack).

I decided to use PVC profiles to isolate and reinforce the battery pack.

Steps:

1.- Glued and isolating each 8 cells in a package. Fixing with hot glue and american tape.



2.- Preparing nickel strips.
Flux in nickel strip to weld bms wire (with tin).



Welded cooper wire in nickel strip (first weld all wires before weld strip on cells for prevent overheat in cells).



Preview...

.

To be continue...

 

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First half pack finished and working in second half pack.





Second pack finished.



The second pack has a better finish (experience?) Diferences...



Sorry for the language. I don't speak english correctly.

 

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My own spot welder.

Has a old 16f84 uc, 16*2 alphanumeric LCD and a solid state relay with a triac. The machine have a programmable pre-shoot, a dead cicles between pre-shoot and shoot, and a programable shoot. I can configure a % of cycle and a number of cycles of pre-shoot and shoot. See the oscilloscope and LCD to understand.



Example of spot welds.