Hi all
I bought this battery tester:
https://it.aliexpress.com/item/1005001381541786.htmlIt reads 1.59V instead of 1,5V and 9,41V instead of 9.00V.
Current drawn is 5.35mA @1,5V (280 ohms) and 2.04mA @9V (4K4).
The internal voltage converter is a XC6385, giving 3.0V at the output. It should work at 0.9V minimum.
The third digit is a bit weird... It shows a number when I attach the power supply, but if I adjust the voltage it doesn't change anymore... 1.51V, 1.41V, 1,31V... But if I retry, it shows 1.52 or 1.53...
I'll try to adjust it, also adding two resistors to raise current drawn (22 ohms for 1,5V and 470 ohms for 9V). I could also keep only the converter and make a new meter with a ATmega328P and a 0.96" OLED display...

Mechanics appear to be good.
Note: on 1.5V contacts it measures also 3.7V (3.2/4.2V) from Li-ion batteries, but they don't fit!
