If your phone only charges when it’s switched off, you likely have low input power, a dirty or damaged port, moisture locking out charging, or heavy background drain that exceeds what the charger supplies. Start with a known-good 15 – 30 W charger and cable, clean the port, then test software and battery health.
- You see a liquid/moisture alert every time you plug in. Don’t override it; let the phone dry and use wireless charging until it’s gone.
- The port looks physically damaged or the phone only charges at certain angles. Port repair time.
- Swollen battery or the back cover lifting. Stop using and seek service immediately for safety.
Why it charges only when switched off
Not enough input power
Wall adapters and USB ports deliver different amounts of power. A basic PC USB 2.0 port tops out at about 500 mA at 5 V (2.5 W). If your phone idles around that or higher, it may not gain charge while on, but will charge once it’s off (because draw falls). Using a proper USB-C PD/PPS 15 – 30 W adapter usually fixes this.
Dirty or bent charging port
Lint and dust pack into USB-C/Lightning ports and stop the plug from seating, which lowers current or causes intermittent connections. Carefully cleaning the port often restores normal charging.
Moisture detection lockout
Modern phones block wired charging when water is detected in the port to prevent corrosion and damage. Charging might appear to work only when off because the system is less active or you’re seeing intermittent detection. Don’t force it dry the phone properly first.
Background drain or buggy apps
If apps or services are burning power in the background, your phone can consume more than a weak charger provides, so the percentage stays flat or drops while on. In Safe Mode (Android) or after closing problematic apps, charging returns to normal.
Firmware glitches or post-update weirdness
Updates occasionally trigger charging or battery quirks that a restart, cache clear, or new cable fixes. Always test with another adapter and cable, then update again if a patch ships.
Hardware faults: battery, port, or charging IC
A worn battery, loose port, or charging/PMIC fault can present as “charges only when off.” If known-good power + clean port + software checks don’t help, it’s service time. Using wireless charging can keep you going short-term because it uses different hardware paths.
Step by step fixes start from here
1) Sanity-check power and cable (3 minutes)
- Try a known-good 15–30 W USB-C charger that supports Power Delivery or PPS and a certified cable. Avoid low-power PC USB ports.
- Reseat both ends firmly. Try a different wall outlet.
- Watch for improvement with the screen off. If it charges while off but stalls when on, you’re likely under-powered or the port/cable is marginal.
2) Clean the port safely (2 – 4 minutes)
- Power down. Use a light to inspect.
- Use a soft brush or dust blower to remove lint. Avoid metal picks and liquids. Re-test charging.
3) Rule out moisture properly
- If you get Liquid Detected on iPhone or Samsung moisture icon, unplug and let it air-dry. Do not use heat or rice. Try again after 30 minutes; if still present, wait longer or switch to wireless charging short-term.
4) Software tests
- Restart and test again.
- Android: Open Settings → Battery → Battery usage to spot power-hungry apps. Then try Safe Mode to see if charging improves with third-party apps disabled. If yes, you found a software side-cause.
- Update the OS and check again (both Android and iOS).
5) Try wireless charging as a workaround
If your phone supports Qi or MagSafe, wireless charging often works even when the port is flaky, letting you keep using the phone while arranging repair.
6) Still stuck? Service checklist
- Angle-dependent charging or visible port damage → port repair.
- Battery swelling or sudden drops/shutoffs → battery replacement. Stop using it until serviced.
Android-specific steps
Check Battery usage and rein in background drain
Settings paths vary, but you’ll find Battery usage to identify apps spiking consumption. Consider Battery Saver or OEM background limits to reduce drain while charging.
Use Safe Mode to isolate app issues
Boot Safe Mode to disable third-party apps. If charging improves, uninstall recent or high-drain apps until normal behavior returns.
Know your charger: PD/PPS basics
Pixels and many Android phones prefer USB-C PD or PPS chargers for full speed. Older or cheap adapters may fall back to low current, explaining the “only charges when off” symptom. Choose a 15 – 30 W PD/PPS brick from a reputable brand.
iPhone-specific steps
Liquid detection alerts
If iPhone shows Liquid Detected for USB-C/Lightning, unplug and let it dry. Apple explicitly advises against rice or heat. Use wireless charging if needed until the alert clears.
Cables and adapters
Check for frayed or damaged cables, try another USB-C or Lightning cable and Apple-compliant adapter, and test a different outlet.
Table: Symptom → Likely cause → Quick fix
| Symptom | Likely cause | Quick fix |
|---|---|---|
| Charges only when off | Under powered adapter or poor cable | Use 15 – 30 W PD/PPS charger and certified cable; avoid PC USB ports. |
| Charges at certain angles | Debris or bent pins in port | Power down, gently clean; if pins look bent, repair port. |
| “Moisture detected” or liquid alert | Water in port triggers safety lockout | Unplug, let it dry; switch to wireless until clear. Don’t force charge. |
| Stays flat while screen on | Background drain > charger input | Battery usage review, Safe Mode test, use higher-wattage charger. |
| Works with wireless only | Port or cable path faulty | Use Qi/MagSafe temporarily, book port/B2B board service. |
| Random shutoffs, swelling | Battery failure | Stop using, get battery replaced. |
Featured Snippet (Q → A)
Q: Why does my phone only charge when it’s switched off?
A: Because input power is too low, the port is dirty or damaged, moisture is blocking charging, or background drain exceeds the charger’s output. Start with a 15–30 W PD/PPS charger, clean the port, check for moisture, and test in Safe Mode.
Q: Is it safe to charge if the phone shows a moisture alert?
A: No. Unplug, allow the port to dry, and try again later. Use wireless charging until the alert clears to avoid corrosion or damage.
Q: Can a weak USB port on my PC cause this?
A: Yes. Standard USB 2.0 ports provide up to about 500 mA at 5 V. That may be less than your phone’s on-state draw, so it only gains charge when off. Use a proper PD/PPS wall charger.
Q: What’s the fastest way to tell if software is the problem on Android?
A: Boot into Safe Mode. If charging speeds up or the percentage finally climbs, a third-party app is likely the culprit. Uninstall suspects.
FAQ
1) How do I safely clean a charging port?
Power off. Use a flashlight. Gently dislodge lint with a soft brush and use a dust blower. Avoid liquids and metal tools. Re-test with a known-good cable.
2) What does “Liquid Detected” mean on iPhone?
The phone sensed moisture in the connector and temporarily blocks wired charging. Let it dry naturally and try later. Apple advises against rice or heat.
3) What wattage charger should I use?
For most modern phones, a 15 – 30 W USB-C PD/PPS charger is a safe, widely compatible bet. Lower-power ports can fail to keep up while the phone is on.
4) My phone charges fine wirelessly what does that mean?
Likely a port or cable path issue. Wireless charging uses different components, so it can work even when the port is flaky.
5) Could a bad battery cause this?
Yes. Degraded or swollen batteries behave unpredictably. If you see swelling or random shutoffs, stop using the phone and get service.
6) After an update, charging is weird. Now what?
Restart, try another charger/cable, and apply any patches. Some issues clear with a reboot or minor update.
Conlusion
Phones that only charge when off usually have low input power, dirty or wet ports, background drain, or hardware wear. Use a solid PD/PPS wall charger, clean the port, respect moisture alerts, test Safe Mode on Android, and use wireless as a stopgap. Seek service for port damage or battery issues.
Source: Apple Support | Google | Wikipedia | Samsung
