The real reasons your phone battery is rubbish - and how to solve them

How to solve rubbish battery life

Battery life is the bane of smartphone owners everywhere. It's lovely being able to browse the net, play games, watch videos and update your status from everywhere and anywhere. But enjoying it too much can turn your phone into an expensive paperweight – at least until you get home and get it plugged in.

All is not lost though, as there are numerous ways to eke out a little (or a lot) more juice from your ailing battery. But while there are tonnes of 'guides' telling you how to save your power very few ever bother to explain why.

What difference does having a bright screen make? Why do you need to turn off the buzzing? Should you be turning GPS and Wi-Fi off, or does it not really matter at all?

We spoke to some engineers from the big phone firms to find out the answers and give you more information on why your battery can inexplicably die.

Don't let your phone get too hot

A hot battery isn't always avoidable, but if you're not sure what's causing your processor to work so hard check your task manager, in case there's anything clogging things up in the background. You can stop anything that looks suspicious.

Beyond that, environmental heat will affect your battery. You can help it out by avoiding excessive warmth – that might mean not leaving it near a radiator or on the dashboard of your car, or near other electronics that are pumping out heat.

If a battery does get too hot it can cause it to degrade faster and extreme temperatures can even cause the electrolyte in the battery to ignite, starting a fire (though this is really, really rare).

Why does heat matter?

In the short term, lithium-ion batteries like the ones found in smartphones can actually perform better at high temperatures, as the heat lessens the internal resistance, which in turn can speed up electrochemical reactions. However this also stresses the battery, causing it to degrade faster and hold charge a little less well.

Generally there's only a significant impact on the battery if the temperatures reach fairly extreme levels and many phones even have built in ways to combat heat. We asked a Samsung spokesperson about the effect of heat on their phones and they stated the following:

"Our devices have temperature controls built in to ensure that the device and the battery will never get to a detrimental temperature, so if the device heats up we can downscale the processor to reduce the temperature."

So you shouldn't worry too much, but if you notice that your phone is getting hot try to remedy it.

Don't let it get too cold either

Extremely low temperatures are also best avoided as they increase the internal resistance of a lithium-ion battery, by slowing down the electrochemical reactions, causing it to work less efficiently.

As such batteries that are especially cold are likely to see a decrease in performance, though cold conditions have no real long term effects on a battery, so it should return to normal once warm.

Turn off vibrate

The vibration function on your phone, along with haptic feedback, uses a tiny motor which rotates a weight at high speeds to turn electric energy into kinetic energy and cause the phone to vibrate.

Our spokesperson explained that the motor, operated for a short period of time before being turned off and then on again, creates short spikes of current which use more energy than a sustained level.

The energy required to do all that is not insubstantial and is actually a bigger drain on the battery than a ringtone, which only requires a small vibration to produce sounds through the phone's speakers.

So unless you're really attached to that vibrate function turn it off and turn your ringtone on. Or just turn them both off and embrace the lunacy of never being able to tell when your phone is ringing.

Lower the screen brightness

Just having the screen on is one of the biggest battery drains for a phone, and obviously the bigger the screen, the bigger the drain. Having it brightly lit sucks the power down harder than an aggressive shower drain, as the phone requires more power to sustain a bright light than a dim one.

So turn it down.

What's wrong with bright?

We asked our Samsung spokesperson why phone screens are such a battery drain and they explained that a screen simply converts electrical energy into light energy. On a full HD or QHD screen the energy required to change the colour of each pixel is substantial. On top of that, brighter screens require more electrical energy to convert into light energy.

Many phones have very bright screens anyway so you might find that you can comfortably drop the brightness to around 40% or lower.

Alternatively you could activate the 'auto brightness' mode that most phones have, which will automatically adjust the brightness as needed, dimming it when your surroundings are dark and brightening it when they're light.

It could also be worth adjusting how long it takes before your screen switches itself off. If it stays on for two minutes every time you get a text, or check the time, that can quickly add up so consider lowering it to more like fifteen or thirty seconds.

Don't leave Wi-Fi on unnecessarily

If you leave Wi-Fi on without a connection (for example when out and about) your phone will keep checking for Wi-Fi networks and constantly trying to connect to open ones, which uses power and can be a significant battery drain, so turn Wi-Fi off when you're not connected to a network.

Similar principles apply to Bluetooth, GPS and 3G/4G. So if you're not using them, turn them off.

Modern batteries and CPUs are designed to minimise these effects, so the issues aren't as bad as they used to be, but if you really want to save power this is a real pro tip.

Check what's draining your battery

Any app or system process can potentially drain your battery as they all require CPU power to run and some also download data (for example an app that's syncing).

It's not always obvious which the main culprits are, especially as apps often run in the background, so it's worth checking and luckily most phones come with task managers that make this simple.

If it turns out you've got a rogue app on your hands at least then you'll know to delete or disable it, or if for example you find that the screen is the main drain, you'll know to turn down the brightness.

It's rarely necessary to close apps completely, but it's worth keeping an eye on your task manager even if you're not noticing shorter than normal battery life, just so you can see what's actually running.

Activate your phone's battery saving mode

Many phones come with some form of built in battery saving mode, such as the 'STAMINA' mode found on Xperia handsets such as the Sony Xperia Z3+, which stops apps from syncing or checking for notifications and messages when the screen is off, then lets them work as normal as soon as you turn the screen back on.

Sony's method also maintains your IP address so that you will instantly have internet access once the screen is turned on again.

However, the current breed of flagship phones have a new trick: Ultra / Hyper / Extreme power saving mode.The Samsung Galaxy S6 has such a trick, where it will make the phone as powerful as a Nokia 3310, with only calls and texts allowed through - although you can choose to have data as well.

And let's not forget Windows Phone 8 /10 handsets have 'battery saver' which only lets apps run when you open them and turns off email auto-sync.

Charge your phone efficiently

The effects of charging patterns on lithium-ion batteries are pretty minimal. That said, if you want to maximise the usefulness of your battery then in general you shouldn't let it drop below around 20%. Once you do charge it you should charge it to at least 80% rather than doing lots of little charges. However there's no need to charge it right the way to 100%.

You also shouldn't let it run down completely too often as this puts extra stress on the battery. It can be worth intentionally draining the battery completely and charging it to 100% once every month or so to calibrate it, so that the battery reading on the phone remains accurate, but don't do it more than that.

Don't let your phone's battery stay flat for an extended period of time as it can become unstable. Lithium-ion batteries have a built in fail safe which causes the circuits to be destroyed if you try and charge a dangerously unstable battery.

This means that it isn't particularly dangerous but it will destroy your battery, which is a serious problem if it's sealed in your smartphone.

Turn off live wallpapers and motion effects

The movement from a live wallpaper uses your phone's graphics processor as it has to process motion and potentially visual effects. A static wallpaper on the other hand has none of that and so is much friendlier on your battery.

The parallax effect in iOS 8, which causes the icons and background image on your screen to match the movements of the device, tasks your phone's graphics processor in much the same way as a live wallpaper.

The effect can be minimised by going into 'Settings', then 'General', then 'Accessibility' and then switching 'Reduce Motion' to 'On'.

Use dark wallpapers with OLED screens

If your phone has an OLED screen (like the Samsung Galaxy S6 and many other Samsung handsets) it's worth switching to a dark wallpaper, as OLED screens light pixels individually rather than lighting the whole screen.

So a wallpaper with a lot of black won't require as many lit diodes as one with a lot of white and will therefore use less battery. If on the other hand your phone has an LCD screen (like the HTC One M9 or iPhone 6) this isn't a factor, so you can go wild with the brightest wallpapers you can find.

Prevent apps from syncing in the background

We asked a Samsung spokesperson about the impact of apps constantly synchronising on your battery and they replied with the following:

"Smartphones are becoming more and more efficient at maintaining data connections to the internet.

"However the reality is that every time your phone makes a data call to the network this uses battery power, therefore if you minimise the frequency of these calls by syncing less, you make less calls and therefore save battery too."

It's also best to only have apps sync over Wi-Fi, as 3G and 4G are even bigger battery drains, not to mention potentially costly if you don't have a big data allowance.

Use a battery saver app

Depending on your phone, it might be worth using a battery saver app to eke as much life out of your battery as possible.

There are loads of these available from app stores, for example 'DU Battery Saver' on Android, which gives you estimates of how long your battery will last or take to charge and gives you the power to optimise it with battery saving modes.

Having said all that, many phones already have built in battery management, such as the battery saving modes detailed above, so those will in many cases be all you need.

• Want to know more about the technology in your battery? Check out our in-depth feature on just what's under your battery cover.