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The OPUS Conundrum
#1
As the OPUS BT-C3100 is somewhat the de facto charger/tester in this forum I would like to share some insights and observations I have had with the 3 that I have. As far as I know they are genuine all ordered from the same supplier within a 3 months time frame.


I had the good fortune of getting 80 ninebot 18650 battery packs with 20 LGGM261865/LGGEM261865 2600mAh cells in each pack for a total of 1600 cells.
The preliminary tests were very encouraging (the IR, V, and mAh results on the cells were good) so I decided to do an experiment on all my testers by slot.
The date code, IR and V was recorded before they went into the testers, then after the C/D/C cycle had completed the mAh, IR and V was recorded.
All IR and V tests where done with my RC3563.
After about 200 cells there appeared to be a pattern developing.
The OPUS was consistently low on the V reading. As a matter of fact in some instances the reading was so low if I had waited to check this cell after a ≈30 day resting period I would have claimed it a SD and binned it. I shudder to think how many cells I binned after the 30 day test, that had low V from the OPUS to begin with and fell below the 4.1V threshold but yet had good IR and good capacity.

By comparison all my other testers had acceptable V readings.

One interesting measurement that we can glean from this though is that since the cell never attained full saturation the amount of V loss after a resting period of at least 25 days was minimal. The average V loss over the resting period was 0.014V where the others came in at 0.023V to 0.028V
One thing I did notice, was, that at times when the ambient temperature was a little bit higher the V came up a bit but not by much.
So if you are using the OPUS testers check your cell voltage after the C/D/C cycle has completed as that is the V you want to use to determine if the cell is a SD or not.
Analysis of the testers.

Snipp of the sheet used.


Wolf
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Great prices and superb service.
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#2
LGGBM261865/LGGEM261865 test very well although I only had a couple batteries with LGGEM261865 cells .
I have another 59 batteries to harvest.
4 Opus BT-C3400 placed on top of three 120 mm fans externally powered( found that this lowered the mAh by 50 to 100 same as a80 mm fan mod connected directly to internal fan connector)
mAh range 2528-2820 average 2675
YR1030+ IR between 34-49
My testing isn't done to the precision that your testing is. But it is good enough for me.

Later floyd
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#3
(06-30-2020, 02:21 AM)floydR Wrote: ......................mAh range 2528-2820  average 2675 ...............
...................YR1030+ IR between 34-49..................
floyedR,

I did get a fair share of the LGGEM261865s
My highest IR so far was 46.62  with a dismal 90% SOH  Tongue
Although it seems to be a SD Sad


My Average , Min and Max stats so far:



Wolf
For Info Google Drive

Great ABB shunt breaker seller River City Industrial
Great prices and superb service.
 [Image: em2566%20(1)__19172.1521541365.jpg?c=2]

Not your average Wolf       
            Cool
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