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i alredy taken it apart, when i check the voltage of the battery it shows around 3,6 v, battery alredy shows 0% so idk if 3,6 v is result of battry having no charge left or broken battery, if i can somhow diagnose problem further, i can do it, i just dont know how or where and what i can check.
Is this a good question?
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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:
2. Charging IC/PMIC
The Power Management IC might be faulty. Common symptoms:
3. Battery BMS Protection
The battery's internal protection circuit might have locked out because voltage dropped too low. You can try:
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:
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
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@mleem 1. but how exactly, where to put probes to check those, i think i got the charging port cause i saw 5 v,when plugged (idk if i checked in correct place),no visible corrosion, idk whe to put probes to check flow, 2. phone dosn recognise charger, voltage present (i checked in the same placee as before) its still 3,6 v 3. i dont know how to do it (video link would be helpful) 4. no corrosion visable. on a motherboard i see, little dots where i think purpose of are to put pobes in, when i check in diffrent combinations i see 3,6 or 3,4 v, i dont know if this information helps but im doing my best here, from eqiupment i have buisness toolkit, heating mat, the tool that blows hot air up to 450C (idk english name for it), and soldering iron, i dont have variable power supply, but if you have or know any good one you can tell me cause i plan to buy one in the future
If you want to chek the flow on the Board you need the "com" on the V- or GND, and the red one on the part you are testing. NOte: If you reverse these on a board (Red to Ground, Black to Test Point), a digital meter will simply show a negative number (e.g., $-5V$). It works, but it can be confusing if you are trying to troubleshoot logic levels.
For a battery it should be irrelevant where to put which probe. At least if you have kind of a modern Multimeter (like my auto-Multimeter). If you are using an older analog meter with a needle: Probe placement is critical. If you put the probes backward, the needle will attempt to swing left (below zero). This can physically bend the needle or damage the internal mechanism (the galvanometer).
@mleem im using the ifixit one , when i check VBAT, between GWD,TH andTD it shows 3,6 everywhere
3,6 seems to be just fine for the battery. It is the "0%" state, where the phone still should start and say "hey I'm empty". Try to measure through to the USB Port.
5V at USB port present?
├─ How: Black probe → USB port metal shield (GND)
│ Red probe → VBUS pin inside USB port
├─ NO → Port/cable/charger defective
└─ YES → Continue to VBAT
VBAT rising while charging?
├─ How: Black probe → GND (USB shield, large GND pad, or battery minus)
│ Red probe → VBAT testpoint on board OR battery connector plus pin
│ Measure for 30-60 seconds with charger plugged in
├─ NO → Charging IC/PMIC/FET defective (Board-level repair / charging module replacement needed)
└─ YES → Works, but battery possibly too weak
TH resistance normal (10-100 kΩ)?
├─ How: **Battery disconnected**, multimeter set to Ω
│ Black probe → GND pin on battery connector (on motherboard)
│ Red probe → TH pin on battery connector (on motherboard)
├─ NO → Thermistor pin defective, possibly blocking charging
└─YES → OK
Important:
For voltage measurements: Keep black probe on GND, move red probe to test points
For resistance: Battery must be out, measure at the board-side connector
Don't short adjacent pins with the probes!
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@jan54210 you have the phone open so go ahead and take a well focused pictures of what the phone shows you with the cover removed. Make sure the image is well focused and large enough. That way we can zoom in and hopefully show you where to measure and where to place the probes. Adding images to an existing question
Common issues with not charging are:
bad charger/charging cable
failed charging board (Sub_Board, Daughter board)
Damaged ribbon cable from charging board to main board
Damaged PMIC (Power Management IC)
Bad battery/connector.
@jan54210 reconnect all the ribbon cables, reconnect your charging board. Connect your battery. Place the probes as shown and note the voltage. Note: you may have to scrape the masking on top of the test points a bit, since they may act as an insulator.
Now connect your charger to the charging board. Measure the voltage the same way as before. Let us know what voltage you get.
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@oldturkey03 done
3,6 v no matter with charger or without
@jan54210 okay. You need to post a close up of the USB C connector on your charging board. WE need to check the voltages on the board side to see if you are getting the right voltages. If you do, then the issue can be the flex cable coming from the sub-board to the main board or it is the PMIC on the main board.
@odlturkey03 changed the battery, thats not it
@jan54210 that leaves the charging board as well as the ribbon cable from the charging board to the main board.
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