phone charging

Is Fast Charging Bad for Your Phone? We Set the Record Straight

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Power discs, power banks, power adapters, wireless chargers and more – there are countless fast-charging devices and tools available to premium phone users. But even with the plethora of fast-charging cables and accessories at our fingertips, one can’t help but wonder: is it safe? 

While keeping your battery charged is a top priority, is fast charging bad for your phone? Can the lithium-ion battery overheat or even deplete or weaken its power source over time? The answer to this question is highly debated and complicated. But we’re here to set the record straight. Plus, we’ll offer a few reputable fast-charging accessories.


First, what is fast charging? Let’s explain. 

A regular USB port puts out 2.5 watts of power. Anything above that is considered a fast charging device, but since consumers desire the fastest charge possible, you can find fast-charging devices and accessories that reach anywhere from 10 watts to 60 watts (for something substantial like a laptop). However, for a phone, a lightning fast charge would be a fast charger of 25 watts (think power adapter). 

Fast-charging wireless chargers, which use the Qi standard to transmit power over airwaves, can reach the same wattage. But they are generally slower than a fast-charging wire or power adapter. Still, they are pretty convenient. 


We’ve all felt our phone warm in our hands as it charges. It’s not unusual – it is generating power, after all. However, can a fast-charging device actually do more harm than good? Can it actually cause the phone to overheat and overextend the battery?

Generally speaking: No! There is some truth behind this thinking, which we’ll explain in a bit. But first, it helps to understand how fast chargers work to efficiently and safely charge your phone.  

Discover FUEL Fast Chargers

Fast charging operates in two stages. The first stage pumps a ton of power into your phone, boosting the battery as quickly as possible. This comes in handy when your battery is completely drained, giving you something to work with for emergencies, etc. However, after 10 to 30 minutes, your phone will hit 50 to 70 percent charge. Once this happens, your fast charging device enters the second stage. It will slow its roll, so to speak, so your phone’s battery doesn’t overheat. 

That being said, you can only fast charge a phone that is equipped to do so. Some older phone models – like the iPhone 7 – may not even have a fast-charging system. If your phone is designed for fast charging, using a standard charger won’t harm it either. Not sure if your phone is built with fast charging capabilities? You can always verify the specs on the website. 

Is fast charging bad for your phone? The short answer is no. While anything can happen, your phone is perfectly safe. Aside from a faulty design or technical issue in the battery or fast-charging device, fast charging is not bad for your phone. But there is one caveat: stick to a reputable manufacturer like Case-Mate for your charging accessories.


It’s no surprise that overheating the phone’s lithium-ion battery causes harm. But as we’ve demonstrated, a fast-charging device and a fast-charging phone will give it the boost it needs in a two-step process, slowing down toward the end to avoid overheating and subsequent damage. But there are some common things you might do that are indeed bad for your battery. 

Reaching Low Battery Levels

Allowing your phone to reach extremely low power levels is not great for it. It can cause a chemical reaction that harms the battery’s lifespan. Luckily, newer phones now feature a battery management system that will safely save the battery and power down the phone. Still, it’s safer to avoid these low battery levels, plugging in your phone before it reaches below roughly 25 percent power. 

Extreme Temperatures

Extreme temperatures – like leaving your phone in a hot car in the day or freezing tent at night – can really do some damage. Instead, try to keep your phone on you at all times to combat extreme temps.

So, is fast charging bad for your phone? As long as you use a compatible fast-charging device that is built from a reputable brand – like Case-Mate! – your battery and phone are safe and sound. 

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