phone not charging when plugged

Hey @jan54210!

Okay, so your Redmi 10 shows 3.6V battery voltage but won't charge and stays at 0%. You've taken it apart - good start. This is actually a common issue and there are a few things to check:

3.6V is basically a dead Li-ion battery. Normal range is 3.7-4.2V. Below 3.6V, the Battery Management System (BMS) often refuses to charge because it thinks the battery is damaged.

What to check/diagnose:

1. Charging Port/Board

Since the battery voltage is present (3.6V) but not charging, the issue is likely the charging circuit on the motherboard or the charging port flex cable:​

• Check for corrosion or damage on the USB-C port
• Measure voltage at the charging port when plugged in (should see ~5V)
• Check if current flows into the battery (use multimeter in series if you can)

2. Charging IC/PMIC

The Power Management IC might be faulty. Common symptoms:​​

• Phone recognizes charger but battery doesn't charge
• Voltage present at battery but no current flow

3. Battery BMS Protection

The battery's internal protection circuit might have locked out because voltage dropped too low. You can try:​

• Force charge the battery externally using a universal Li-ion charger at low current (0.5A) to bring it above 3.7V​
• Then reconnect to phone and try charging normally

4. Battery Connector/Flex

Check the battery connector on the motherboard - any corrosion or bent pins will prevent charging.​

If you have access to a variable power supply:​

1. Disconnect battery from phone
2. Connect power supply to battery terminals (+ to +, - to -)
3. Set to 3.8-4.0V, limit current to 0.5-1A
4. Charge for 5-10 minutes until voltage reaches ~3.8V
5. Reconnect to phone and try charging normally

This can "wake up" the battery's BMS if it's in protection mode.​​

Based on Redmi 10 common issues - it's usually the charging port flex cable or the PMIC (charging IC) on the motherboard. Check those first before replacing the battery.

Let me know if you need further Help.

Best Wishes

Marvin