The Efest Lush Q2 is a fairly basic fast charger. It has led indication of full charge and fixed charge current. According to the specification, it will charge a single battery at 2A, 2 batteries at 1A. It will charge all of the battery sizes stated on the box:
The charger is powered by mains only:
With one battery, charge current was around 1.9A up to 4v, then it gradually drops. At termination, the battery voltage was 4.2v which dropped to 4.17v when the current cut off:
With two batteries, charge current was around 0.9A up to 4v, the batteries come out at just over 4.2v:
That’s interesting how the voltage on yours rose so steeply. I tested it twice with a singlr battery to make sure it wasn’t reaching the claimed 2A, and it looks like you got avout the same current. I use a Medusa Research Power Analyzer which saves the data as CSV file, then I import it into Excel to produce the graph.
With the singlr battery I found that as soon as the charge current stopped, the voltage dropped from 4.2v to 4.17v, confirmed with a fluke multimeter, but from your graph it looks like the terminal voltage is above 4.2v.
I wouldn’t use “Lush” as a name for any device. But it’s not as bad as the bike light that Xeccon decided to call Goatsucker ( I think that was a poor translation of vampire bat).
Most of the time I also limits my measurements to that, but there it is hard to get any measures below about 3.5V with a normal LiIon cell, the voltage raises fairly fast above that level.
This time I tested with a load and a LiFePO4 cell and they both gave the same result at lower voltages and it do not match your result.
And my regular charge curve also starts at about 1.9A, even when the cell voltage is below 3.6V
All my measurement are done at 1 second intervals. When I do the voltage sweep with the load it takes about 15 minutes because I do it in 0.01 volt steps and takes two measurements at each point.
Then it sound like it is the input filtering on you equipment we see, not the real values. My measurements are not depend on fast sampling, if I needed fast sampling I would have to write some other software for my DMM’s (Bench DMM’s can often sample fairly fast).
Or is it even more simple: You only have one point at the start of the slope and one point at the end of the slope, nothing in between?