Ok, here’s an update:

  • Banggood will refund me 19 USD for the S9 after I sent them the video that I linked in the first post
  • I messaged Simon from Convoy on aliexpress, he offered to send me a new driver. I asked him if the new driver would have the same cheap charging circuit with no real cut-off, he hasn’t replied yet. I’m assuming since it looks very much like a design flaw and not like a malfunction, it’ll be the same.
  • I ordered an A6 + MC1 from banggood since my brother values the true moon mode more than charging via USB. – OT: I didn’t dare to order the 5A tint again because the last one had such an outright ridiculous light color, so I went for the 3D… apparently my brother and I are part of the minority that actually prefers tint closer to neutral (even if they go into the green slightly) over straight up pink :smiley:
  • Since I somewhat know my way around electronics, I’ll have a look at the driver in the S9 soon. Maybe there’s something “obviously” wrong with it, like wrong values in a resistor divider to measure battery voltage (taking into account what mcu is being used… if it’s marked at all. Guess I’ll find out).