Is it safe to charge my phone overnight? Top tips to extend battery life

(Pocket-lint) – Modern smartphones, tablets and laptops with lithium-ion batteries take a lot of charging. But when’s best? Is overnight too much? Does keeping it topped up damage the battery?

We’ve tried to dispel myths and clarify how your phone, tablet and laptop batteries work so you can get the longest life out of them day to day and in the long run.

Overnight charge

The myth about overcharging your phone is a common one. The amount of charge going into your device shouldn’t be an issue as most are smart enough to stop taking a charge once full, just topping up as needed to stay at 100 per cent.

The problems occur when the battery overheats, which can cause damage. To avoid this it’s best to remove any case on your phone when charging over night. It’s also best to leave the phone on a flat, hard surface so the heat can dissipate easily.

So it’s perfectly safe to charge your phone overnight, just make sure it doesn’t suffer from overheating. That said you’ll be surprised how quick phones can charge today, so you don’t really need to leave it charging for 8 hours. One solution to slow down the charging is to use a wireless charger. It will save you fumbling to plug it in and mean you aren’t using as much power to do so. 

Charging when really hot or really cold

Most devices are designed to work in a wide range of temperatures, say between 16 to 22 Celsius, but exposing your device to high temperatures regular above 35 degrees could damage it.

Apple for example will temporarily shut down your device if it gets too hot. The company suggests that “Charging the device in high ambient temperatures can damage it further.”

Thankfully it’s not the same for cold temperatures and batteries are far more suited to dealing with the cold. You will probably notice your battery performance go down – cameras are especially prone to this on skiing trips, however the poor performance is normally only temporary and you should see usual battery life return once you get back to warmer conditions. 

Battery memory

Battery memory is a pretty old concept that applied more to Ni-Cad batteries of old, rather than modern lithium-ion packs. So where you previously thought letting a battery fully dissipate before charging was best you now need to do the opposite.

A lithium-ion battery is best kept between 50 per cent and 80 per cent charged so as to use the charged ions and keep battery life prolonged. So charging in short bursts throughout the day is probably the best way to keep your phone going in both the short and long term.

That’s a lot easier with wireless charging. Both Android and iOS allow you to use Low Power Modes to extend the life of your battery over the day, allowing you to preserve your battery further.  

Stick with official chargers

While you can use any charger for a lot of phones, like Android devices, it’s best to use the official one.

Chargers from the big brand names have been checked, checked and rechecked to perfection to ensure an optimum, and more importantly, steady charge. Once you start using third party chargers you’re entering risky territory where you may end up damaging your battery without realising it.

Charge cycles

Where charging from nothing to full may have been good in the past we’ve got to reiterate it’s now the opposite. Your lithium-ion battery has a limited number of charge cycles so it’s best not to use them up.

Rather than letting your laptop, phone or tablet completely die and then charge it from scratch you’re better off to keep the battery topped up with lots of small charges, rather than a full cycle. If you do use full charge cycles you’ll find the battery suddenly stops taking as much charge and loses it faster and faster as it breaks down.

Apple iPhone users, for example, have a feature in iOS that will tell you the health of your battery and whether it’s due for replacement. You can find the check in Settings, Battery, Battery Health. 

Leave it half charged when storing 

Many companies, including Apple, believe that you should store your gadgets with around 50 per cent charge rather than full charge or no charge:

“Do not fully charge or fully discharge your device’s battery,” explains Apple. “charge it to around 50 per cent. If you store a device when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge. Conversely, if you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life.”

It’s also advisable to turn it off if you know that you aren’t going to be using it for a while rather than letting it slowly run out of battery while it’s on the shelf not being used. 

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Why not check out our Future batteries, coming soon: charge in seconds, last months and power over the air feature to see how we’ll power our devices in the future. 

Writing by Stuart Miles. Editing by Alex Allegro. Originally published on 2 February 2015.

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