So, is charging your phone overnight bad for the battery? Read this article to learn the truth.
Can Charging Your Phone Overnight Overload the Battery?
Depending on the device, it can be important to only charge a battery for a specific amount of time to avoid overloading and ruining a battery. However, with most modern devices (and all current mobile phone batteries), protection chips monitor when the internal lithium-ion battery hits full capacity. When this happens, charging is immediately stopped. So you can’t overload the battery in this way. The problem is, as the phone keeps dropping back to 99% capacity, the charger will kick in again and recharge it to 100%. This is called trickle charging, and it’s not good for your battery’s lifespan, as we’ll cover below.
Will Charging Your Phone Overnight Start a Fire?
Most likely, the heat generated by charging your phone battery will not be enough to start a fire. However, most experts recommend leaving your phone in an open, non-combustible space – just in case. This means not charging it under a pile of loose paper or clothing and definitely not under your pillow. If you smother your phone and allow the heat generated by charging to build up significantly, you can also damage your phone’s battery. This doesn’t mean you should cool it down too much, though. Lithium-ion batteries don’t do well with either extreme heat or extreme cold, and either is likely to damage it. Temperatures below 32℉ (0℃) or above 158℉ (70℃) are liable to degrade your lithium-ion batteries.
Will Charging My Phone Overnight Degrade the Battery?
Most likely, leaving the phone charging will degrade the battery. As we’ve mentioned above, if you leave your phone on charge overnight, you’re likely to be doing one of two things that will damage the battery’s lifespan. You are either letting it trickle charge for hours on end and letting it get too hot. If you need to charge your phone overnight, you should follow these tips to minimize any potential damage:
Charge your phone on a hard, cool surface to avoid it overheating. Avoid placing it under your pillow (or anything that will trap heat). Remove your phone’s case before charging. Unplug your phone if you wake up overnight. Stick with your phone manufacturer’s official charger and charger cable. These are purpose-designed for your phone and are less likely to have faults that may damage your battery or cause slow charging. If you’re using a power bank, make sure it’s high-quality and isn’t likely to damage your battery.
Should I Only Recharge My Battery When It Reaches 0%?
No. Letting newer lithium-ion batteries reach 0% capacity can actually damage them. Batteries will inherently lose capacity over time – it’s just how they work. This myth came from older nickel-cadmium (NiCad) batteries. These would develop a “memory” which effectively cut their capacity if you didn’t fully discharge them. Experts recommend keeping lithium-ion batteries between 30-80%. Ideally, you should monitor your phone’s charge and try to keep it between these values. If you go a little under or over it isn’t the end of the world.
How Can You Get the Most Out of Your Batteries?
The easiest solution is to charge your battery only when you can monitor it. This way, you can stick to the recommended margins of around 30-80% and maximize its lifespan. This means fully charging your phone before bed or after you wake up, rather than letting it trickle charge all night long. Another option is to invest in a “smart charger” which you can schedule to turn off after a specified number of hours. This way, you can charge your phone overnight with no worries of burning up its lifespan. If you are charging overnight, try to avoid using fast chargers, as they can cause unnecessary heat build-up over time that may damage your battery. If you want to learn more about batteries, read our definitive guide to charging.
Staying Powered Up
Charging your phone overnight isn’t necessarily a bad idea, depending on how you do it. But, if you aren’t careful, you could reduce the battery’s lifespan, leading you to buy a new phone earlier than you planned. Generally, though, phone batteries will only last for a couple of years anyway – even with the best practice. So, if you occasionally need to charge your phone overnight, don’t worry about it too much.
