In this thread I will post pictures of the batteries that I’ve built, both for work and for personal use. I am working at an ebike company part time as a battery builder and electronics service man. I also accept orders from DIY enthusiasts via PM .
Workplace builds will be used in low power ebikes, so those are sometimes built slightly differently. Personal builds will be used mostly in high power esk8s. Once I have some customers I will also upload build pictures of those packs in here.
PS: Sorry for some of the pictures’ quality, my phone’s camera is not perfect .
My setup:
- Kweld spot welder
- Varta Blue Dynamic 574 012 068 car battery (kweld reports about 1350A)
- KSGER T12 soldering iron
What I have built so far, in chronological order (last updated: 2023 December 28):
#1 - 12S6P 30T mountainboard brick pack (December 2022)
Yes I know I’ve done an overkill amount of welds. Did it because of trying to get it as solid as possible. I’ll jump this pack on my mountainboard. Also this might go into an efoil later down the line, so I did everything overkill. Where the series connection is not the nickel, it’s 3x 10AWG. Wanted to use 3x 12AWG originally, but I didn’t have enough 12AWG left. The terminal wire is 8AWG, and is terminated in a QS8. The 8AWG wires are soldered onto the nickel in the full length of the nickel, this was done before welding to avoid heat soaking the cells.
PS: some of the welds are too hot and at a few spots I blew right through the nickel. Once the electrodes on the Kweld first discoloured, I had to bump up the settings a bit. And once I sharpened the electrodes with a dremel I started to get too hot welds and blew through the nickel a few times. Took some time until I figured out that I had to lower the energy by a very significant margin… This was my first time sharpening / cleaning the electrodes. Also I didn’t have proper lightning and I absolutely had to finish the welds that day… Didn’t help in getting the welds just right. Also learning material kind of.
PPS: ran out of black wire in a suitable gauge, so I had to use red for the charge negative as well. It’s for personal use only anyways, so it’s not gonna cause trouble.
#2 - 10S2P 50E ebike brick pack (December 2022)
An easy ebike brick pack, running the discharge via the 20A Daly BMS. Max current it’s ever gonna see is 14A, hence the 16AWG wire.
Instead of wrapping the whole P groups in fishpaper, I just placed the inner material of the fishpaper rings onto the contact points:
Also, yes the welds are a little hot. This was my first time welding .2 mm nickel so I was still dialing in the welder. They hold really well though.
For the other work packs that are similar, I will follow a similar construction.
#3 - 10S2P 50E ebike brick pack (December 2022)
An easy ebike brick pack, running the discharge via the BMS. Max current it’s ever gonna see is 14A draw. Improvement from the first one is that I have the negative terminal on the other side, which makes the B- BMS wire routing more convenient.
#4 - 10S2P 50E ebike brick pack (December 2022)
An easy ebike brick pack, running the discharge via the BMS. Max current it’s ever gonna see is 14A. Same construction as #2.
#5 - 10S3P 50E ebike brick pack (December 2022)
An easy ebike brick pack, running the discharge via the BMS. Max current it’s ever gonna see is 14A. Easier than the 10S2Ps I’ve made before, because of the way the cells are arranged. I can just weld up full rows and use simpler shapes of nickel.
#6 - 10S5P 50E ebike brick pack (January 2023)
An easy ebike brick pack, running the discharge via the BMS. Max current it’s ever gonna see is 14A.
#12 - 10S3P 50G ebike pack with split P group (April 2023)
This pack took way too much time. Convincing me to build another pack with a split P group would probably take some persuasion The story behind it is that we quoted the customer for a 10S3P, but had to order a different BMS that would arrive quickly. Could only find a 30A, which is much bigger than the 20A I was looking for. With the 20A there would have been space for another cell length wise, if the BMS was standing… But I realised I can still do the 10S3P with a split P group, so… Here it is.
#14 - 13S3P 50G ebike flat pack with flexible style connections (November 2023)
Was a fun pack to build, it didn’t have to follow the flex pack layout, could have used nickel series connections actually. But thought I’d make a proper flex pack for practise. In the end I still hot glued the rows together though