"Over Charger Voltage" error: non-QC phone triggering 6 - 12V on QC charger(s) - eviltoast

I’ll write what happened in steps as it occurred (the problem starts at steps 4-6, if you want to skip to that):

  1. After waking up I noticed my phone was only at 50-something % after charging for 6 hours overnight from 30%. The USB tester it was connected through read constant 1.36A (around 7W). No abnormal heating observed.
  2. Assuming this was kept constant, the phone should have received 42Wh overnight. I rebooted the phone, tried charging it turned off, percentage remained the same. “Whatever you say then…”
  3. I tried different adapter (Xiaomi). Near-15W for a few seconds, then back to 1.36A. I often see this exact figure, thus I assume the phone learns my charging habits and slows down. I tried changing the time from around 04:30 to 12:30, but this made no difference.
  4. I tried the official USB-C PD 66W adapter. Unfortunately, I do not have a USB-C tester, but Ampere app reported >5A and the percentage was indeed going up quickly.
  5. I connected it back to the previous adapter, finally getting near-15W at 5V as anticipated.
  6. I just put a small fan back on top of the screen (not necessary, but it was on that 66W adapter for a bit before - the cooler the better) as usual and was about to leave it charging, but soon heard a strange notification sound. Upon unlocking I was greeted with the error shown.
  7. Glancing at the USB tester, it was erratically jumping between 5V, 6V and 12V, protocol jumping between “Unknown” and QC 2.0.
  8. I reconnected it with the same results.
  9. I switched to Xiaomi power adapter (the suspicious one being Motorola), no issues observed at first. I assumed power adapter failure.
  10. I shortly connected the phone back to the official 66W adapter to asses potential damage. Everything worked.
  11. I connected the phone back to the Xiaomi adapter without a USB tester, and once again got the error shown (this time on a different QC-compatible adapter). Re-connecting with a USB tester the issue didn’t show up again.

Devices list

Phone

Ulefone Armor 24 (version shipped with Android 14) - 85.14Wh

USB Tester

FNIRSI FNB18

Cables
  1. HOCO USB-A (4-pin*) to USB-C data + charging
  2. Choetech 240W USB-C to USB-C 2m
Adapters
  1. Motorola TurboPower 15W (USB-A)
  2. Xiaomi TurboCharge 33W (USB-A*)
  3. Ulefone 66W PD (USB-C) - (11V 6A for 66W)

* Regarding the 4-pin USB-A: Xiaomi breaks standards by utilizing USB Power Delivery via 5-pin USB-A with their proprietary cable.

Thanks for any ideas.

  • u/lukmly013 💾 (lemmy.sdf.org)@lemmy.sdf.orgOPEnglish
    1·
    24 days ago

    I made an interesting observation. This only happens after using the Ulefone charger up until reboot. Furthermore, after using the Ulefone charger, the phone cannot communicate with my laptop over USB-C to A cable, and keeps quickly disconnecting and reconnecting over USB-C to C, again just until reboot.

    Possibly, the Ulefone adapter is faulty, confuses the phone’s controller and that in turn confuses the QC adapters making them output random voltages.

    Edit: Hmmm, acts the same on QC adapters, then falls to 1.36A.