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):
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.
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.
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.
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.
#13 - 13S2P 50G ebike brick pack (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
#15 - 21S4P P42A brick pack for my new board RaceBro (February 2024)
Built to deliver 13kW of power. 8AWG terminals, 0.2 nickel, 3x12AWG series connection in the middle.
It has survived when my MakerX D100S burnt down and decided to short the pack out.
I forgot to take pictures of the finished pack but this is the first time when I made laser cut fishpaper for a battery pack - it’s just so much more convenient! I built this the same way as #1 just with the laser cut fishpaper.
This is the first time where I used double sided tape for laying out the wiring. It speeds up the work by a fair amount.
#28 - 13S3P #11 LG M50L ebike brick pack (May 2024)
Thanks! Yeah these packs are really small. These aren’t high end ebikes though, they are just pedal assists. Mostly lower end stuff. The company’s biggest battery pack is just over 800Wh.
When it comes to the TS100 the power supply you’re using matters more than you’d think. I have no problems with 10awg wire on mine and the 8awg wire wasn’t too hard either but I mostly just removed the old unneeded 8wg stuff so I haven’t soldered with it a lot.
Damn, that was hard to find to be able to quote the voltages available. The kit I bought included the 24v power supply so I haven’t had any issues with getting my iron hot enough so far, but it seems that when you get the lower voltage supplies it will struggle to stay hot enough for larger wires.
Oh yeah. There is a noticable difference. Forgot to mention that I actually use a boost converter to up the voltage from the laptop PSU to 24V when soldering at home with the TS100. While doing the 8AWG and the 10AWG I did use 24V. The 8AWG terminals were a chore. 10AWG was fine, but while I am soldering onto the nickel which is already welded, I would prefer something faster, to transfer less heat into the cells.
Actually while looking at the display of the TS100, it still wrote 400C even when trying to heat up all the solder on the 8AWG, which means that I am not power limited, the thing limiting the heat transfer is the max heat of the iron. With the TSGER T12 I could go up to 480C, at which point I would probably be power limited, but any extra temperature over that 400C is appreciated.
Ran out of black wire in a suitable gauge for my 12S6P. It’s for personal use only anyways so I just used some red wire for both the negative and positive on the charge terminals
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.
A 13S2P 50G pack from November
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
I forgot to take pictures of the finished pack but this is the first time when I made laser cut fishpaper for a battery pack - it’s just so much more convenient! I built this the same way as #1 just with the laser cut fishpaper.
This is the first time where I used double sided tape for laying out the wiring. It speeds up the work by a fair amount.
#28 - 13S3P #11 LG M50L ebike brick pack (May 2024)
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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.
. Good luck on your venture.
