There are a few key reasons why your phone may get hot when it’s charging:
Fast Charging Generates Heat
Many modern smartphones now support fast charging technologies like Quick Charge or USB Power Delivery. These allow your phone to charge much faster than normal – often reaching a full charge in under an hour.
The downside is that fast charging requires higher amperages and converts more electricity to heat rather than charging the battery. The fast conversion of electrical energy to chemical energy in the battery generates significant amounts of heat.
This excess heat is the main reason your phone gets hotter when using fast charging. Quick Charge and other fast charging standards are simply pushing your phone’s charging circuitry to its limits, which inevitably creates heat.
Processor and App Usage While Charging
Another factor is that you may be using your phone more while it’s charging. Modern phones allow you to continue using apps, play games, watch videos, etc even as the battery charges.
Your phone’s processor and GPU generate heat when operating at high loads. Things like gaming, navigation, or streaming HD video can make your phone heat up noticeably.
If you’re doing processor or graphics-intensive tasks while your phone is also fast-charging, it’s no wonder the device gets hot. The combination of fast charging and heavy app usage is a recipe for phone overheating.
Poor Heat Dissipation
Phone designs can also contribute to overheating when charging. Many modern smartphones use metal and glass designs that look very sleek and premium. However, these materials are less effective at dissipating heat compared to plastic phone bodies.
Plastic chassis allow for more ventilation and airflow to cool phones. But with glass and metal phones, it’s harder for heat to dissipate from the processor, battery and other internal components.
This is especially true if your phone case fits very tightly or you have a thick protective case. The tighter the phone is sealed inside a case, the harder it is for heat to escape.
Older Battery or Charger
Over time, your phone’s battery capacity will degrade naturally. An older lithium-ion battery will have less charging efficiency and is more likely to heat up when fast charging.
Using an older, slower charger can also lead to more heat build-up when charging. Your phone may pull maximum current from an underpowered charger, leading to a slower charge time and more excess heat.
Make sure to use the charger that came with your phone for optimal performance. Third-party chargers may be inconsistent with voltage and amperage ratings, which can affect charging heat.
Charging in Hot Conditions
The ambient temperature also plays a role. Charging in a very hot environment like a hot car or outside in summer can exacerbate overheating issues.
Your phone already generates internal heat from charging or usage. If the surrounding temperature is very high, it becomes much harder for the heat to dissipate through the chassis and into the air.
High ambient temperatures combined with other factors will significantly contribute to your phone overheating while charging.
Faulty Battery or Other Hardware Issue
In some cases, an underlying hardware problem in your phone may be the root cause of abnormal overheating. Issues like:
- Swollen or faulty battery
- Damaged charging port
- Debris build-up in charger port
- Damaged temperature sensor
- Bad power management chip
Could all manifest symptoms of overheating when charging your phone. If the problem persists even after trying different chargers and ruling out other factors, it may be worth getting your device inspected for hardware defects.
How to Keep Your Phone Cooler While Charging
If your phone feels uncomfortably hot when charging, here are some tips to help keep it cooler:
Avoid Heavy Usage When Charging
Don’t play graphics-intensive games or stream 4K videos while also fast charging your phone. The combination will make your phone get much hotter than usual.
Light usage like messaging, web browsing or social media is fine, but avoid processor or GPU-intensive tasks. Give your phone a break while it’s charging.
Use a Slower Charger
Fast charging makes your phone charge faster, but trades off greater heat build-up. Use a slower 5V/2A charger for cooler running temperatures.
Also try using the charger that came with your phone – others may not regulate current properly leading to excess heat.
Remove Protective Case While Charging
If you use a tight fitting case, especially a thick rugged case, try removing it before charging your phone. This allows for better heat dissipation.
You can also periodically remove the case if your phone feels too hot while charging.
Don’t Charge in Hot Areas
Avoid charging your phone in hot cars, outside in direct sunlight or other hot environments. The ambient temperature will make it much harder for your phone to stay cool.
Use a Cooling Pad or Stand
Cooling pads or stands with built-in fans can help direct airflow over and around your phone while charging. Just having your phone elevated can also improve passive cooling.
Clean Out Charger Port
Carefully clean out any lint or debris buildup in your phone’s charging port. Blockages in the port can affect charging performance and heat dissipation.
Check for Hardware Issues
If your phone gets abnormally hot when charging even after trying other troubleshooting, get it inspected for potential hardware defects like a faulty battery.
Replacing an old swollen battery can help your phone charge cooler and more efficiently.
Is it Safe to Use My Phone While Charging?
Modern smartphones are designed to be safe to use while charging. However, the combination of fast charging and heavy usage does push your phone’s limits and make it get hotter than ideal operating temperatures.
While not inherently dangerous, excess heat can degrade your battery and other components over time. It’s best to avoid overheating your phone whenever possible.
Here are some general guidelines for safe charging and usage:
- Don’t fast charge while gaming or doing other processor/GPU-intensive tasks
- Use a slower charger for lighter usage like web browsing or messaging
- Periodically stop charging if your phone gets too hot
- Don’t charge inside hot cars or environments
- Don’t wrap your phone in blankets/clothing as it charges
- Avoid using third-party chargers and cables
Following basic precautions will allow you to charge and use your phone safely without overheating. Monitor your phone’s temperature and adjust conditions if it feels uncomfortably hot.
How Hot is Too Hot For a Phone While Charging?
There aren’t official guidelines on exact overheating temperatures, but general consensus is:
- Under 113°F (45°C) – Safe normal operating temperature
- 113°F to 131°F (45°C to 55°C) – Warm, monitor the phone
- Over 131°F (55°C) – Too hot, stop charging/use until it cools down
You can download apps to monitor your phone’s temperature if you don’t have a thermometer. Also pay attention if your phone feels hot to the touch – that’s a good indicator to stop charging and let it cool.
Sustained temperatures above 131°F (55°C) while charging/using your phone can degrade the battery. It’s best to stop charging if your phone reaches this point and give it a rest.
When to Worry About Overheating While Charging
Occasional mild overheating is normal, especially with today’s fast charge technologies. But some warning signs indicate a more serious issue:
- Very hot even when not charging or doing intensive tasks
- Overheats repeatedly despite troubleshooting
- Display, camera or apps become unresponsive
- Phone feels burning hot to the touch
- Strange odors or noises from phone
- Visible smoke or leaks from phone
If you notice any of these, stop using your phone immediately. Severe or repeat overheating can permanently damage phone components in some cases.
Other signs of trouble include:
- Battery dies very quickly
- Battery expands or swells
- Performance deteriorates
- Random reboots/shutdowns
Take your phone to a repair shop if you can’t resolve overheating issues. A faulty battery that can’t regulate temperatures properly often needs to be replaced.
Frequently Asked Questions
Why does my phone get hot while charging but not when using it?
This comes down to different types of load on your phone’s hardware. Charging uses the battery, voltage regulation chips and power management systems at maximum load over a sustained period.
Whereas when using your phone, the processor and graphics chip are under heavy load but only for brief bursts. So charging tends to cause your phone to heat up more overall than normal usage.
Is fast charging bad for battery life?
Fast charging won’t directly affect your battery’s lifespan provided temperatures remain in check. However, the additional heat generated can accelerate aging of the battery.
To maximize your battery’s lifespan, avoid fast charging constantly. Use slower charging when you don’t need the phone fully charged urgently.
What should I do if my phone won’t turn on due to overheating?
First, disconnect the charger and remove any case or coverings so your phone can cool down. Don’t attempt to turn it on or use it. Place the phone in a cool spot and give it at least 15-30 minutes to return to safe temperatures.
Once cooled, see if you can turn on the phone. If it powers up normally, the overheating was likely the cause. Monitor temperatures closely moving forward.
If your phone still won’t power on after cooling down, it likely has a different hardware issue you’ll need to get inspected.
Is it OK to charge my phone overnight?
Overnight charging is generally safe if using the original charger that came with your phone. Just be sure to use a standard low amperage charger.
Don’t use overnight charging with fast chargers as the extended high heat is not ideal. Also avoid charging overnight in very hot rooms or enclosed spaces that limit ventilation.
How can I tell if my phone’s overheating is from hardware or software?
If the overheating only occurs during charging, it’s likely a hardware issue like the battery or charging components. Whereas if the phone overheats consistently even when not charging, that points to a processor, memory or software-related issue.
Try rebooting your phone to rule out any software glitches. If the overheating persists across charging, use, and reboots – take your phone for professional inspection to identify hardware faults.