Can bad battery cause overheating in phones?

Overheating is a common issue that many smartphone users face. It can cause performance problems, damage components, and pose a safety risk in extreme cases. One potential cause of overheating is a bad or failing battery. In this article, we will examine how battery issues can lead to overheating in phones.

What causes phone batteries to go bad?

All lithium-ion batteries degrade over time and through repeated charge cycles. As the battery ages and becomes less efficient, a few key problems can develop:

  • Loss of charge capacity – The battery holds less charge and depletes faster.
  • Increased internal resistance – More resistance to current flow leads to inefficient charging/discharging.
  • Swelling – Chemicals inside the battery expand, causing it to swell.
  • Internal shorts – Damaged separators allow electrodes to touch, shorting the battery.

These issues reduce the battery’s ability to deliver power smoothly and efficiently to the phone system.

How can a bad battery lead to overheating?

As batteries degrade, they become less able to provide steady, stable power to the phone. This can cause overheating in a few ways:

  • The battery may struggle to provide enough current. The phone has to work harder, stressing the processor and generating excess heat.
  • An unstable, fluctuating power flow causes components to heat up and cool down repeatedly.
  • Swelling batteries take up more space and physically touch or press on heat-sensitive components.
  • Short circuits within the battery result in uncontrolled current flow and excessive heat generation.

Overexerting the battery by charging too fast, fully discharging, or demanding high currents for apps/games also exacerbates these issues. The phone’s thermal management system gets overwhelmed and cannot properly dissipate the excess heat being produced.

Signs of overheating due to a bad battery

Here are some telltale indicators that your phone may be overheating due to battery problems:

Phone gets noticeably warm during normal use

As the battery degrades, it struggles with routine workloads and causes the phone to heat up. This often happens during relatively simple tasks like browsing the web, navigating apps, or light gaming. A healthy battery would not significantly warm up the phone under these moderate loads.

Charging problems

Difficulty charging is a major red flag for battery issues. This includes slow charging, the phone getting abnormally hot while charging, or charging intermittently stopping/starting. The battery is essentially “resisting” being charged and the excess effort results in overheating.

Battery depleting faster than expected

Faster than normal battery drain is a sign the battery is not operating efficiently. Your phone’s battery life is noticeably reduced despite similar use patterns. The battery is unable to properly deliver power, causing components to draw more current and generate extra heat.

Random shutdowns/restarts during use

If your phone randomly shuts off or reboots even with sufficient battery charge remaining, it is likely due to the battery’s inability to maintain steady voltage/current. The unstable power flow forces the phone to reset once thresholds are exceeded.

Swelling or deformity

A swollen battery is clearly damaged and will run hot. Check for any abnormal swelling along the battery/back of the phone. In some cases, swelling batteries even warp and deform the phone chassis itself. This creates internal physical pressure and added heat.

Diagnosing the root cause

If you suspect your phone’s overheating issues stem from the battery, here are some steps to help confirm the root cause:

Check battery health/capacity

Most phones have a feature in settings to check battery health and view current maximum capacity compared to when new. Severely reduced capacity points to a battery nearing the end of its lifespan.

Test with different battery

Try swapping in a known good, fresh battery if possible. See if the overheating persists. Use an OEM battery specifically made for your phone model. Significant improvement with a battery change confirms the old battery was faulty.

Battery usage logs/graphs

Analyze battery usage patterns through your phone settings. Irregular discharge curves, abnormal usage when idle, and metrics that don’t add up can indicate impending battery failure.

Repair shop evaluation

Mobile repair technicians have the expertise and equipment to accurately test batteries and detect issues. They can perform diagnostics and determine if the battery needs to be replaced. This is the best option if you lack the tools and experience yourself.

Resolving the overheating problem

Once a faulty battery is determined to be the culprit, here are your options to resolve phone overheating:

Replace the battery

This is the most direct solution. Swapping in a new battery from a reputable brand will provide stable power delivery and normal operating temperatures. Use manufacturer approved batteries for your specific phone make and model.

Use external battery

An external battery pack or charger can provide backup power and allow you to use the phone without straining its damaged internal battery. However, you still need to eventually replace the faulty internal battery.

Limit screen brightness

Keeping brightness lower reduces power draw and associated heat generation. Disable auto-brightness and manually lower brightness as much as comfortably usable.

Avoid intensive apps

Restrict use of power-hungry apps and games that tax the phone hardware and battery. Limit 3D gaming and video streaming which heat up the phone. Opt for lighter apps that require minimal processing power.

Add a cooling pad/heat sink

Physical cooling accessories can help dissipate heat more effectively from the phone’s chassis and internals. This compensates for the heat caused by a bad battery.

Consider replacing phone

If you need to continually replace the battery, the phone itself may be too old and degraded. Battery failures in quick succession indicate it may be time for an entirely new phone. Evaluate the cost/benefit of further repairs on an aging device.

Safety tips for using a faulty battery

Using a phone with a damaged battery presents potential safety hazards. Here are some important precautions to take:

  • Avoid leaving phone unattended while charging – Monitor it closely.
  • Never sleep near a phone charging overnight – Charge in a safe place outside bedrooms.
  • Stop use if battery expands/warps – Discontinue charging or using.
  • Avoid excessive heat exposure – Don’t leave phones in hot cars.
  • Replace battery ASAP – Don’t delay necessary battery replacement.
  • Use manufacturer approved batteries – Cheap, off-brand batteries increase risks.
  • Inspect charger condition – Use undamaged USB cables and adapters.

Damaged lithium-ion batteries can in rare cases catch fire or explode. Take sensible precautions until you can get the phone battery replaced.


In summary, degraded batteries that have lost capacity and efficiency often create overheating problems in phones. The inability to deliver stable power forces internal components to overwork and generate excess heat. Diagnosing battery issues requires testing capacity, observing usage patterns, and detecting physical deformities. The ultimate solution involves replacing the worn out battery with a new one. Take safety measures when using a phone with a faulty battery prone to overheating. With proper precautions and new battery installation, the overheating problem can be resolved.