I had some spare time during my vacation so I finally built a more solid version of my shunt and voltage divider "breakout" board which I used to measure the performance of LiIon chargers with.
I soldered everything onto a small breadboard and adopted the programming a little ...
|Improved Data Logger for Charger Measurements.|
During the first tests, some error spots are still left. The two DuPont cables that lead from the charger to the board don't make solid contact, need to solder my own ones. And when moving the plugs in the USB ports of the computer, the voltage and current delivered are changing a little as well.
|The first test: The DuPont cables for connecting|
the charger need to be replaced.
Also used a USB hub so only one connection is used on the computer. Turns out that the plugs show similar behaviour on the hub when the computer is moved - you can clearly still see every movement test.
The charger seems to get even less disturbed looking at the charging curve. >1A until 4.20V are reached and then the current drops slowly, while the voltage rises up to 4.25V for a short time. This is all within LiIon specs and looks quite nice.