After some testing I felt ready to start. I started by solder the balance wire before spotwelding since I’m not very good at soldering yet.
Not perfect shapes, tried to not weld in the middle of the batteries negative pole but I think I did on some.
Nice welds, thats what i look for, the nickel left behind the steel cap when pulling off.
That’s looking good! Please use some kapton tape or something insulating to cover the parts of the battery you have already welded so you don’t short the battery by accident.
Thx! 
Got abit over confident and held the electrodes to close to the end and a bit sideways. Result was a bad weld.
Could this create a problem later?
I will when I have done one side of the pack. Now the backside is not connected so I am safe:)
I don’t think so. As long as you didn’t burn the fish paper or destroyed any of the insulation between plus and minus.
It was just a small splash, I managed to clean with a small tool so I think it’s good. Going for welds more inside of the strip.
Did some testing on how I want to do the end + and - strips.
I’m thinking of 6x 1.5 mm2 cables to one bullet connector. This to even out the load of the cells.
Other side of bullet I’m think of AWG 10(5.27mm2) cable to connect to BMS.
I drilled holes and made the cable go though and around before I soldered.
What do you think?
i like the abundance of caution but 6 wires is overkill i think.
usually like one 10 or 12awg wire soldered along the length of the final nickel strip is the usual.
having said that, if no fitment issues, your idea is good too.
Actually, they should be at an angle. But if you get strong welds who cares
Thank you for your great answers.
I Think this is overkill as you say but I like to put some extra work when I do it so i can trust it when I ride.
Also I am bit new to soldering so my plan was to find a solution where I can solder before I weld the strip.
The BMS will be on top so I got some space to put them together
Aha, thank you for informing me.
My problem at first was that I got some bad welds when I put them very horizontal. Now I use them almost vertical, only with a bit of an angle. Maybe some more angle will help.
what spot welder is that and where did you pick it up from? looks great!!
Arduino spotwelder and used car battery for 30 Eur with 600 CCA
Wireplaning, kapton tape, put rubber feet on BMS.
Now I have put it all in a 1150 pelican box and connected it to a 1040 pelican box with two focbox inside. Did water test in the shower without electronics first so I don’t have to worry about water when I run.
This has a layer of kapton between the layers of cable.
There are some improvements left to do, shrink wrap and so on. But it fits nicely in the box and no wires are squeezed. (It is possible to remove the battery from the box.
The battery box for now has 2 velcro straps below and one strap around to hold it.
The board works great, did some testing in the snow and on the frozen lake. The thing just goes!
Thx for all support esk8 forum, this forum has all you need to build a E-MTB.
Special thanks to @Idea for the motor mount:)
Cleaned it as good as i could after out running so no salt would break it :).