Dinky Battery 13S-1P

docw009

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Illinois, Not far from Wayne's World.
I purchased the Battery Hookup Molicell M42's last month. Tested one at 4.2Ah on my Littokala tester with a 500ma load. Made a 13S-1P brick to see how they worked. Makes for a nice compact battery. My load tester says it's 3.8AH with a 3A load. I was disappointed with that, hoping it would do better than 90%. On the other hamd, 26 bucks for the cells, $16 for the BMS, $5 for the rest, it's OK.

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What to power with this tiny battery? I tried my Tong Sheng TSDZ2 conversion. It has the OSF formware, but still only pulls 11.8A max. Typically uses 6-8 wh/mile,

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The road test got me 25 miles before the battery died. I had used 3AH to reach 22 miles, suggesting a real world life of 3.5AH.

I also did some other tests. I spot welded a short length of 8) mm .15mm nickel* to a P42 cell, about enough to do a series connect from one cell to another. I put this on my load tester and eventually got to pulling 20 amps thru it.

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The P42, nickel, and wires stayed cool for the tests. I put my IC resistance meter on the metal strip. It use two point probes and is pretty precise for small voltages.

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I'm looking at 22 millivolts at 20A. If that's accurate, then with 26 of these series tabs, that's .57 volts in losses at 20A. I'll probably be in the 4-5 A range, so the resistive drop is small at 100 mv. For the kind of packs I make, which are mostly for 20A bike controllers. I think the 10 mm wide .15mm thick nickel will be enough. It's about the limit of my spot welder anyway.

*EDIT: I originally wrote 10 mm nickel, but re-measured it, and it was 8 mm nickel.


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Seems to me like it puts a critical perspective on their 45A/cell claim. Is that 45A at nominal-ish voltage, or 45A at 1V?

Not that it matters much, because it would be a rare cell tab that could carry 45A without turning into an incandescent filament, or else destroying the cell in the process of being welded on.
 
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