Updated October 18, 2026: Removed reassurance that electrical noises are generally harmless and added clearer battery-fault and emergency actions.
A phone that is hissing, popping, swelling, smoking or becoming unusually hot needs immediate attention. Do not keep charging it or run repeated tests to find out whether the battery is responsible. The U.S. Fire Administration lists hissing/popping, bulging, venting gases and rising temperature among lithium-ion battery warning signs.
If there are warning signs
- Stop using and charging the device. Disconnect external power only if you can do so safely without touching a dangerously hot or damaged device.
- Keep people away. If it is smoking, venting, rapidly heating or burning, move away, avoid the fumes and contact the local emergency service. Do not carry an actively failing device through the home.
- Do not open, press, puncture or bend it. Do not try to push a swollen screen or case back into place.
- Arrange professional guidance. Contact the manufacturer or an authorized repair service when it is safe to do so. Tell them about the noise, damage, heat and charging conditions.
If the phone is safe to leave alone, stop handling it. Do not prioritize a data backup over a suspected active battery failure.
A sound alone does not identify the part
A notification, speaker, vibration motor, charger or camera mechanism can also make a sound. That does not justify dismissing an unexplained hiss as harmless coil whine. Note whether the sound clearly comes from an external charger or from the phone, and whether there is heat, odor, visible damage or a change in the case shape.
Do not shake, squeeze or recharge a suspect phone to reproduce the noise. If there are no danger signs and it was clearly an ordinary notification or playback sound, normal sound settings may explain it. Persistent unexplained noise should still be assessed.
What to tell the repair service
Record the model, approximate battery age, any recent drop or liquid exposure, the charger/accessory in use and when the symptom began. Take a photograph only from a safe position. A useful description is “hissing while charging with unusual heat,” rather than a remote diagnosis of a particular internal short circuit.
A damaged lithium-ion battery should not go into ordinary household waste. Ask the repair provider or local battery-disposal service for instructions, and disclose that it may be damaged before transporting it. Do not mail it through a normal parcel service without the carrier’s approved process.
After the fault is resolved
Use compatible charging equipment and follow the phone manufacturer’s temperature and charging guidance. For an iPhone accessory, check the exact MagSafe battery-pack compatibility after the fault has been resolved. Replace damaged cables or accessories through a suitable support route. A magnetic power bank is not a remedy for a failing internal phone battery.