Can You Overcharge a Phone Overnight?

Not too many years ago it would have been hard to believe that so much could depend on a small lithium battery, or even a mobile device used predominantly for making calls.

Today, with billions of mobile phone users worldwide, battery life has become a hot topic.

This is understandable when you take into account the many uses we have for these miniature computers. 

No charge means no mobile phone, and this can have devastating effects on your communication, business and even social life these days. Without power in that battery, your mobile device has little use except as a paperweight.

Most people find it most convenient to rev up their phone’s battery charge while they sleep. We’ve all heard that it can be harmful to the device to keep it hooked up to a charger for too long.

Can you overcharge a phone by leaving it on charge all night? The short answer is ‘probably no’.  Let’s see why.  

New batteries for a new age

Many of the myths surrounding mobile phone batteries revolve around a misunderstanding of how cellular devices’ batteries work.

Initially, phones were powered using nickel-based (nickel-cadmium or nickel metal hydride) batteries similar to those we use in torches and such. These batteries had many limitations such as a short lifespan, overheating, overcharging, or not charging fully.

Nickel-based batteries had a knack of ‘forgetting’ their maximum charge threshold if they were only partially charged on occasion.  In this way, they would remember the last point to which they were charged as the maximum and thus never recharge to 100% again.

Due to these shortcomings, mobile phone manufacturers have been using lithium ion batteries in their devices since the early 2000’s. It is thus highly unlikely that you have or ever will own a mobile device with a nickel-based battery.

Can you overcharge a phone?

No, you cannot, thanks to new technologies.

It may be possible to overcharge a lithium ion battery, but can you overcharge a phone by charging it all night? You are unlikely to find out.

Today’s smartphones are smart enough to know when their battery is full. Any excess power provided after that is re-routed to power the phone instead of charging the battery –conserving your battery power.

In fact, Android phones and iPhones are equipped with microchips to protect them from any kind of excess electrical current once they are fully charged.

There are still a few factors that can affect your phone’s battery-charging performance, however.

The trouble with lithium ion batteries

While lithium batteries make up for many of the faults of their predecessors, they do have two small shortcomings-

Internal power meter error

On rare occasions, a lithium ion powered phone may show symptoms of a cyclic memory similar to their nickel-driven peers.

When the internal power meter which measures the level of charge in the battery is thrown off, the device may register an incorrect power reading. This is temporary and can easily be recalibrated.

Simply use your phone until it dies, recharge it to 100% with the power off, then restart it and make sure it shows a full battery.  If it doesn’t, simply switch it off and continue charging. The next 100% reading you get should be accurate.

Temperature sensitivity

Batteries can malfunction due to extremes in both heat and cold.

The electrical current which charges your mobile device does have a heating effect. While the very first lithium ion batteries were guilty of malfunction related to overheating and could even explode from this – your latest smartphone won’t. 

The optimum charging temperature for lithium based batteries is between 5° and 45 °C. Anything above or below that and you’ve got problems.

As the battery warms up during charging it actually charges faster and when it reaches capacity, the battery stops charging and generating heat, any excess heat is dispersed into the atmosphere.

Heat only becomes a problem if your phone case does not allow for your phone to regulate its temperature in this way. Simply remove the device from its case when charging to be safe.

You may be able to overheat your phone if you try hard enough, but can you overcharge a phone? Still ‘no’.

Charge cycles and prolonging battery life

Charge cycles are the only real threat to your mobile device. Nothing lasts forever, and every battery has a finite number of charge cycles in it.

A charge cycle is viewed as one complete charge from totally empty to full capacity.

Even though these have become increasingly more thanks to technological improvements, the day will come when your battery has done its time.

To keep your battery on the go for as long as possible, try to avoid letting your phone run flat before charging it. Keeping it between 50 to 80% charge is ideal.

There are a few ways to preserve your mobile phone’s battery for as long as possible.

Choosing the right accessories

While it is always a great idea to use only the official charger designed for your phone, getting a cheaper alternative isn’t always a bad deal. The outright fakes are usually the problem – not those that own up to be generic chargers.

As long as you stick to a reputable brand of accessory that is approved for use with your device and complies with the necessary legislation, you should be just fine. 

Another important aspect to check is that the third party charger you buy is compatible with your phone’s specifications.

The London Fire Brigade recently released a report on the dangers of electrocution and fire from substandard mobile phone chargers, with some useful advice on how to spot the offenders.

High-speed charging

Can you overcharge a phone with high-speed charging?

Avoid using the fast charge every time you charge your phone. This practice can cause excess heat more often than you device can bear, and ultimately leading to corrosion, but it won’t’ cause your phone to overcharge either.

The facts of life

Most mobile phone batteries are designed to function with high efficiency for a couple of years, which thankfully is about as long as it takes for you to start craving an upgrade.

If you intend to change over to a newer model every two years or so, and you stick to our advice above, you should not experience any problems with the battery life of your device.

 And, don't forget to check out our store for all the accessories for your phones and tablets.