WE COULD ALL do with a few extra hours of juice from our portable products sometimes. Maybe you’re on a long journey with no charger, or maybe your device is old and the battery life isn’t what it used to be. Either way, the result is the same: you need a bit of magic to keep it going.

Well, magic is exactly what we’ve got here. Using the tips and tricks on these pages, you’ll know which power–hungry features you can do without on your iOS devices or Mac to eke out every drop of electricity. And we’ll show you how to check up on your battery, and stay topped up with power on the go!

Playing games taxes more parts of your phone, draining the battery quicker.

How modern batteries work

The science behind the power supply

THOUGH THE SPECIFICS of battery technology have changed over the years, the Lithium-ion (Li-ion) batteries used by gadget makers first appeared in the ’90s, and the principle remains the same now.

A Li-ion battery consists of two electrodes at each end (the anode and the cathode) suspended in a solution that contains lithium ions (hence the name). The ions are positively charged, and are attracted to the cathode, so they move over to it, making it positively charged in turn. This then attracts negatively charged electrons from the anode over to the cathode — and this is how it provides electricity. Electrical flow is basically the movement of electrons through a conductive system — like water running through a pipe. The trick is to make sure that the only path the electrons can take to get to the cathode is via the processor, screen, and so on, providing these elements with the power they need along the way. When you charge a battery, you attract the lithium ions to the anode, reversing the process, ready to go again.

You may know that Li-ion batteries also degrade over time. The reason for this is that some ions become stuck on the electrodes during each cycle of charging, reducing their effectiveness slightly. Consequently, over a period of time, this adds up.


Li-ion batteries are divided into “cells,” each of which does what we’ve just described. A single product is likely to have multiple cells. This is the best way to scale them, since they can discharge together at a higher overall level of power, and be charged simultaneously, more quickly than one giant battery cell would be.

The top six battery hogs

1 Screens

LCD screens have to be powered themselves, but need a backlight too. The result is that they draw a lot of power, especially at brighter settings. OLED screens (used on iPhone X and Apple Watch) don’t require a backlight, so are kinder on batteries.

2 Data streaming

Streaming data at high speeds between your cell and the nearest tower requires a lot of energy. More modern versions are more efficient, but are still major battery killers.

3 Intensive applications

Processors are a bit like car engines, in that they use more fuel the harder you push them. Any task that requires a lot of processing power over a long time — such as converting a video, or the way a game is constantly using a graphics chip — will use a lot of battery power.

4 Wi-Fi

There’s some debate over whether mobile internet is more of a battery drain than Wi-Fi. Either way, sending data over the air from your device to your router (and back) will have an impact on your device’s battery life.

5 Hard drives

Got a Macbook? Then you should know that your hard drive could be the source of a major battery deficit. Think about it — spinning a magnetic disk at thousands of revolutions per minute uses more power than flash storage. If that’s a concern, it might be time for an upgrade.


Who would have guessed that communicating with satellites in low Earth orbit turns out to be taxing? The constant location searching your device does will quickly drain its battery.