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voltage difference before soldering
#1
Hey,
before soldering a parallel pack together (wire cell level fuses)
should I:

1. discharge all to maybe 3v (much work because my cells are stored at about 4v after testing)?
2. not discharge but keep the voltage difference within max 0.2v that means max 2A for a very short time when internal resistance is max. 0.1Ohm ?
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#2
I solder them at full voltage or the voltage they are resting at. I dont see the problem as such. Yes the potential is higher but the time to discharge once more take to much time since i run the full charge/discharge

If the difference is 0.2v at 3V or at 4V you dont get 2A but perhaps 50mA at most. Thats because the potential vs voltage is low.
On other hand betweeen 3.6 and 3.4 you will see 2A easy!

Thats how I do it but of course you can always do it better but above works fine so far.
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#3
My process is....
1) Test the cells to figure out their capacity - leaving them at full charge at the end of that process
2) After several weeks, assemble the cells into packs so the cells+capacity are evenly distributed
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3) THEN, as a 1st step of soldering things up - test the voltage of each cell and discard self-discharged cells (e.g. cells < 4.10v after several weeks sitting) and replace them with extras of similar capacity.

From your description, you may want to consider setting up a process where one of the steps is to check for self-discharge after several weeks Smile
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