I was told to post here.
The drawing I made above. It’s P42A. Those cells can do 45A. I’ll be using 50mm * .1mm wide nickel sheets. Do I just need 1 layer then? I did the math. The sheet can handle 48A.
I used the data from a 7mm * .1mm on the esk8 ampacity chart to get 48A.
50mm * .1mm = 5 cross section.
7mm * .1mm = .7 cross section = 6.61A
5 / .7 = 7.14 * 6.61A = 48A.
So 1 layer should be enough right? I was going to do 2 layers of the sheet.
I was going to buy this.
https://www.amazon.com/gp/product/B0BZVBK6TG/ref=ppx_yo_dt_b_asin_title_o00?ie=UTF8&th=1
My spot welder can only do .1
I’d recommend buying a more capable spotwelder, and use 0.2x30mm wide nickel as recommended.
Stacking nickel is not advised.
Check out this chart
And this thread is really helpful
In general, if you want one or two batteries, it’s not worth it to build them. You can find very capable folks here that can do it for a fee. The end result will be safer, cheaper, and more reliable than a first or second build.
If you want to become a battery builder and invest in the tools and shop needed for that, then it’s advised not to cut corners. At a minimum you’d need a good welder, like Kweld or Malectrics, and definitely follow modern 2024 advice when received from other builders. There are many outdated ways to build batteries that aren’t used anymore for reasons. Stacking nickel is one such thing that used to be common and is rarely if ever done anymore.
I see. Thank you. I have a quick question.
Let’s say that I have 5 cells in parallel. Each cell can output 10A max.
If I have a controller that ask for 25A, at any given time, will the cells output 10A or, will it, at max output 5A for each cell?
If that’s the case, if my controller has a max of 25A, what’s the point in building the connections of my battery (strips and wires and stuff), to be able to handle 50A when it won’t even get that high?
Obviously, this is a perfect world scenario. No resistance and 20% headroom and stuff. LOL.
If the controller is using 25A and you have 5 cells in parallel then each one SHOULD BE supplying 5A in a perfect world. They will likely be slightly different because cells’ internal resistances can vary, wires and nickel have nonzero resistances, et cetera.
Bigger and more capacity means more reliable and longer lasting.
Also, running cells at 5A max when they are 10A cells is, in general, a good idea. It can lead to certain edge-case situations where maybe you could have found a slightly better performing cell to use, but in general using anything below its rating helps reliability and longevity.
I see. this entire time, my 9p cells can give out 45A max but my controller can ask for 120A.
By that math, 120A/9 cells = 14A per parallel connection and 120A per series connection?
I’ve been building for 45A per parallel and 405A per series connection.
So to my understanding, I could use 2x12AWG(180A) instead of 2x8AWG(400A) for my series because it would never go over 120A anyway because the controller is the bottleneck.
Correct? If so, thank you.
and 14A for my parallel instead of 45A?
To answer most of those questions, more details are required.
This checks out, but again, depends on details.
Ok. Thank you for that information. Now I know I can go for a thinner gauge wire for my series connection and thinner strips for my parallel connections. TY.