Less but more powerfull cells?

I’ve been looking around for cells with the best bang for the buck and found these:

With them i can make a cheaper and lighter pack and have higher discharge than i can with samsung q30 wich are only 15A discharge.

I have made some calculations here:


Now my questions are:

Will the battery stay cooler if i have a higher C-rate rather then lower when i pull out the same constant Amp?

Is it going to be a problem with welding them with only 0,2 or 0,3mm x 10 nickelstrip when they might use 20-30A /cell?

I am planning on using some kind of cell-level fuse 20A, 25A? on the positive side connected to a copper or alu bussbar.

I have read that parallell connections dont draw to much current as serial connections, is this correct?
Then maby nickelstrip spotwelded i parallell and thicker better conductive material for the serial.

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I’m not an engineer but speaking from my own long experience.

  1. A lighter battery pack usually means having less li-ion cells in parallel, keep in mind your desired current draw, calculated and apply while leaving yourself some headroom.
  2. Higher C rate means your cells have lower internal resistance resulting in less voltage drop/heat losses within each cell, yes, they usually heat up less.
  3. You can calculate nickel strips current draw capabilities all over this forum and all over the internet in general, get yourself a good quality spot welder.
  4. Parallel battery configuration means you divide a given load across multiple cells rather than a stressing a single cell, resulting in higher current draw capability.
    Theoretically speaking, for example, say you got a li-ion cell rated 10A draw max, if you join/weld 10 cells in parallel you can draw 100A.
  5. Welcome to the forum, read more :slight_smile:
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This thread has a lot of good stuff in it. Spend at least multiple hours studying it. https://forum.esk8.news/t/the-battery-builders-club/720

Also, there are better options than these cells. Battery calculator for eFoil

Thank you!

May i ask what is the weight of the cells in your calculation?

Samsung 30q 48g
Sanyo 2070c 60.2g

On the spreadsheet, If you click on the battery cell data tab you can check the weight or modify them to whatever you’d like.

With a quick look, for my params I had been messing with (15S 1900Wh), the cheapest lightest weight pack from nkon was made with P42A, assuming the prices are all still accurate. Although I’d be tempted to build a monster of a pack with the 50G!

Thank you!

Did’nt see the tab (on my phone) :slight_smile:

But now i corrected weight and price and it turned a little bit mor yellowish, still can’t figure out why my calculations tells the opposite, i mean the cost is simple math cells * cellprice at a given Wh.

Need to change to the real measured Wh i gues.

The discharge Wh really heavily depends on discharge rate. That’s why the excel is such a great tool for pack design.

What’s the weight that you corrected? I can fix the value in the excel.

It was the Sanyo 2070c

But i actually do’nt know the weight, and now when i search for it i get at least three different results:

62g wallmart.com
61.7g imrbatteries.com
60.2g 18650batterystore.com

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