November 11th marks my one year into ESK8, so I figured maybe its time to get into some custom batteries. I have used NESE for my eMTB build (which turned out great, if you are interested, check them out here) and lipos on my cheap urethane build.
I have yet to use a custom welded pack, so I figured why not learn to build them. I knew from past experience in this hobby, buy cheap or buy twice (or many more than twice) so I decided to just go all in and get a KWeld.
It came super fast and looks great, nice work @tatus1969. I wanted to make sure I was getting the best performance possible so the whole time while assembling I was cleaning all contacting surfaces with isopropyl alcohol incase of any dirt or residue that might increase the resistance.
Soldering the XT150 connectors to the 8 AWG cable wasn’t too hard with my 60W iron. Though it might be helpful to get a more powerful one in the future.
I tested it by powering it on with my smartcharger at 12v. Resistance was 2.32 mO, under the manuals 2.5-3.0 mO typical resistance.
Next was to make a case, which I printed in PETG with red PLA letters glued on. Turned out very nice.
Here is the KWeld letters I cut out from the original case file.
KWELD Logo.stl (132.5 KB)
For the battery, I chose a Turnigy Graphene Panther 6000mAh 3S 75C Battery Pack
Stuck to the side is a 3s charge only 3a BMS for easy charging with either a regular 3s 1A wall adapter or 3A through my smartcharger. In calibration on a full charge, I got 1774A. Literally perfect for my cable cable length of 1.2m which has a max safe current of 1800A.
For nickel, I went with a kilo of some 30 x 0.2 mm strip from Aliexpress.
Took around 25 days to arrive and did not rust after it was scratched up and put in salt water for 48 hours. Came in a coffee scale box? Confusing but works well to protect the nickel.
Now lets get to some welding!
I started on a knife blade at 10 J and increased by 5 J on every consecutive weld. I ended up going to 45 J after I took the first picture.
40 J looks nice here but on an actual cell 30-35 J seems more reasonable.
This ends the setup of my welding gear. I will continue to update this thread with work I have done. Hopefully in the future I can make a few packs for some of you here and there. I honestly love tinkering with this kind of stuff. When I’m working on my Esk8 stuff I just put on some Spotify and jam while getting the feeling of building legos again like I’m a little kid again.