Battery charge termination test

JOKE: I wish my hours were also 80 minutes long, just like HKJ’s (3hours = 240min). Then I could do so much more… :slight_smile:

BTW, nice work!

I did fix that, but obvious it takes some time before everything is updated.

Thanks for the review.

One of the charts on here you shared w/ me b/4 its release about 10 days ago!

The PA18650 w/ the red and blue dots which was used to estimate my 0.05v loss when charging w/ the Opus compared to my Fenix ARE-C2!! ~ 100mAh loss!

Capo has connections.thanks HKJ,now I will study it more!

I assume the 30Q went through 42 cycles during the testing (7 voltage termination levels tested with 6 termination currents each). Is it possible the capacity reduction was due to the fact it was a new cell (compared to the old Panasonic that would be already degraded due to the cycling)? Also, could the high voltage of some of the tests have anything to do with it?`

48 cycles, 8 voltages, I did 4.20V twice.

The larger drop may be due to it being a new cell, but I do not know it.

I would expect the higher voltage to cause a bit extra degeneration, that was the reason I did them last.

Thanks for the testing HKJ its on point as always!

How much would this test change if the cell where abused more? Say at a higher discharge rate?

That would wear the cell faster, but do not affect how much energy is filled into the cell during charge.

I sometimes get dizzy looking at a bunch of graphs, but those were indeed extremely interesting. Tons of work there…I don’t even want to know how long that took you. Thanks.

How to present the data and how much data to present is always an interesting challenge when doing my tests. I did try a couple of different charts and this was the best result. A table was completely out, it is mostly useless, except if you are in a spreadsheet and can visualize the numbers.

Most of the time was automated test time.

Thanks for a very insightful series of tests! I enjoyed reading it and if sb still did that it should be stickied. :slight_smile:

This test has the answers for many common questions, I’m sure.
Thanks a lot!

Incredible job! Thanks from Italy (and I suppose also by the whole CPFItalia) :+1:

Sorry, I did not see you question before.
Usual a good reading would be between 4.15 and 4.19 volt. Look at the 4 hour voltage drop chart, somewhere between yellow and green dot (50mA-100mA) on the 4.2V yellow line.
For smaller cells you want to look between the blue and yellow dots (20mA-50mA).

Great test as usual, I would like to see the same test on nimh battery`s to see how end of charge voltage is related to capacity, like 1.39v vs 1.55v what is the capacity difference?

John.

With NiMH it is not as such volt related, I did some test some time ago: Battery Charging NiMH

So, am I right to conclude that on a 18650, and our high powered lights that draw 5amps, <1 minute of turbo use will negate the difference from a almost full charge of 4.15, to a full charge of 4.20…?

Thanks for the detailed test HKJ.

Thanks Henrik

John.

1 minute at 5A is 60mAh used.

Interesting test. Do you know the internal resistance of the batteries you tested? It would be interesting to see the correlation between that and the voltage drop after 5 seconds for the different currents.

Sorry but no, in this test I just did charges/discharges, there was no analysis of internal resistance.
The 5 second drop probably matched the internal resistance fairly well (not perfect), but the 4 hour drop included a couple of slower chemical reactions.

The internal resistance probably changed during the test, i.e. it increased slightly.