I am gathering information because I am thinking about building my own battery packs for two diy board I am building. Biggest battery will be 12s5p molicel p42a. The batteris will be on top of the boards in a small pelican case. It does not need to flex at all.
I watched a lot of YouTube videos, read on this forum and read a book about building lithium batteries… In the book they say it is ok to double 0.2mm nickel for series connections or triple 0.1 nickel if the spot welder cant weld 0.3 nickel. I also read on this forum that we must use 0.3mm for eskate but I can not find why…
Do you think it is ok to get a cheap spot welder like this one. And then triple 0.12 mm nickel for series connections for the type of batteries I want?
If you think it is not a good idea and have a great spot welder to suggest, feel free to share it with me!
I am also looking at this flipsky wich is way more expensive due to the fact that I must also buy a lipo and a lipo charger.
The Malectrics or Kweld spot welders are great- I have both. I’m actually in the middle of assembling the Kweld, 3d printing the case right now. I’ve been using the Malectrics spot welder for about a year- it’s been flawless, though it struggles with .3mm. I suggest using .2mm nickel strip. It can carry about 10 amps @ 10mm width. However, a lot of esk8 builders buy really wide nickel stripping, and then they carefully cut it down to size. It’s time consuming, but it’s ideal, as it allows you to push a bit more current through your packs. As seen here: https://esk8-news-objects.s3.dualstack.us-east-1.amazonaws.com/uploads/original/3X/b/4/b40dbcac729c85aeb4356b46806f18bedf56cad0.jpeg
If they are in pelican case and you use one for both series and parralel wide strip of nickel .15 or thicker is enough to carry the current as you have like 21x0.15mm of nickel to carry the current per cell
Thanks for you reply! Yeah it seems a nice way to do it when you have a spot welder that can weld 0.15mm. I am afraid those cheap spot welders can do 0.1 or 0.12 max. That is why I am thinking about doubling or tripling series connections.
Would 0.1mm nickel would be too filmsy? I think it would carry current with no problem since current flow mostly on the surface of the material. But is there safety issues involved in using stacked 0.1mm nickel that I am not aware of?
You can use it without a case- just be sure that it’s sealed enough that nothing can accidentally get inside the box. You could cut holes for the cables. Though, you want some ventilation. Kweld offers a 3d printed case for an additional small fee, and then there’s users on here that can print just about anything.
No. You don’t want to use that. It’s too delicate and doesn’t have enough mass to sync heat. .15mm minimum unless building for something other than esk8 that uses low current, and isn’t subject to vibration.
You want to build your pack according to how much current your battery pack can make. At least, that’s how I build mine. You want a 12s5p Molicel p42a, so you’re looking at 20 to 30 amps per series connection. I’m not so fond of doubling nickel strip. Nickel to nickel welds are about half as strong as nickel to steel welds. However, I see nothing wrong with doubling your p groups, but I think series connections should be nickel to steel, so, never doubled. There’s a few tricks to get more current out of nickel striping.
You want to build your pack according to how much current your battery pack can make. At least, that’s how I build mine. You want a 12s5p Molicel p42a, so you’re looking at 20 to 30 amps per series connection. I’m not so fond of doubling nickel strip. Nickel to nickel welds are about half as strong as nickel to steel welds. However, I see nothing wrong with doubling your p groups, but I think series connections should be nickel to steel, so, never doubled. There’s a few tricks to get more current out of nickel striping.
You can double the tabs as seen here. This doubles the amount of current you can get, but then you have to collect the current from both sides of your p-groups with something like braided copper, and only after insulating the living daylights out of them.
But honestly, you’re probably better off going with custom tabs cut down from that 30 or 50mm striping. It’s much easier, as you only have to collect current from one side of the battery.
Anyone, what’s your Joules setting on your Kweld for 0.3? I just got some 0.3x8mm for a smaller pack I’m building.
OP, I wouldn’t buy a cheap one if you’re planning to build more than one pack. The Flipsky one has been slightly proven as passable, and is probably way better than cheap ones
Additionally, stacking 3x0.12 is gonna be a pain and probably won’t look that good. That’s also a ton of current capability. Have you checked out the current conductor rating thread?
I would take a read through both that and the battery builders club threads. You’ll learn a lot. Also, nickel series connections are a very old technique. We mostly use 12awg silicon wire or copper braid
