Appreciate it.
I would prefer to do a process that is relatively quick. So the long term discharge is not desirable.
And I don’t really plan on recycling a bunch of cells…
This is such a small pack that the cell cost is not super high…
I’m more so just trying to make use of these Cells I have laying around rather than dumping them off at Lowe’
I feel like the VC8S will be useful to have around and expect I will keep it.
I also ordered the HRM-10 to check out.
But I am considering sending it back.
Self discharge becoming more obvious more quickly at 2.8v instead of near nominal voltage is a great point.
I was thinking used cells and a 4 decimal voltmeter would potentially yield results in a few days.
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Agreed.
I use full charge instead though. It offers the same degree of voltage swing for a charge loss, is easy to set up (just charge and leave for 1-3 days before measuring starting voltage), and the self-discharge is faster. That makes it easier to better sort cells and/or have a shorter test period.
If a decent, high-precision and consistent meter (accuracy isn’t as important for comparing cells) is available, the HRM-10 should work great, then a week is typically long enough to start sorting out the crap. Then check back in another week to start sorting for p-groups.
Just a couple of data points…I had high grade 50PL’s that only dropped about 180uV-200uV a day but some lower grade China junk that was dropping about 7mV a day.
It’s critical to wait at least a day after bringing the cells to whatever voltage will be used so they can settle to their true resting voltage. Three days is much better as the 50PL’s needed that, otherwise their “leakage” would have looked like it was up near 1mV a day.
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The right Tools are nice to have!!!
Discharging to storage voltage.
And I have not checked all the cells.
But at a glance the used Samsung 50s look viable with about 11 mili ohms
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18650
21700
542100 SAFT VL30PFe Lifepo4
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It looks like new EVE 50PL will be available that no longer have the self discharging issue. https://www.nkon.nl/en/eve-inr21700-50pl-5000mah-125a.html
@Battery_Mooch
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18650 battery store Also tried to call it a 125 amp cell at first too, and link the old November 2024 datasheet.
The New Eve50PL had a 50 amp rating and then they bumped it to 70
Here is the newest 2025 datasheet:
The newer CCC/CE 50pl has a different Anode weld, no more central spiral, and it does perform differently.
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The earlier EVE 50PL did not have a self-discharging issue IMO…those were all lower grade cells.
I tested about a dozen of those cells (all non-CCC ) in three different wraps (red and green) and all had incredibly low self-discharge, about 180uA-200uA per day.
The newer 50PL’s with CCC certification do indeed have a different bottom weld and perform just a touch worse than the earlier version due to their slightly higher internal resistance. Check out my test report from a while ago. My Patreon supporters can check out my 40A and 100A continuous Shootouts against other cells too.
THESE NEW 50PL’s WILL BE AROUND IN DIFFERENT GRADES TOO AND THE LOWER GRADE CELLS WILL SELF-DISCHARGE FASTER!
I’m unable to get cells from Nkon but testing self-discharge is very easy. Unfortunately it takes a week of waiting before we can get results.
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