Modern Android smartphones are powerful devices - pocket PCs really - with a wealth of functions that only a few years ago would have belonged in the realms of science fiction.

For all these technological advancements there is a cost, and invariably that comes in the form of reduced battery life. It’s all well and good being able to video chat with friends on the other side of the world, pay for your shopping with your fingerprint, or shoot luscious 4K video, but if your phone is dead by lunchtime then none of this feels quite so impressive. To remedy this there are a number of apps that promise to prolong the life of your digital marvel. Task killers, RAM optimisers, and battery boosters seem like an obvious answer to the problem...or are they? In this feature we’ll take a look to see if loading this software onto your handset will give you more hours, or a few more headaches.

See also: 10 ways to improve smartphone battery life and Best USB power banks

How do battery saving apps work?

These apps aim to make your life simpler by systematically turning off various features and functions on your phone that could exhaust the battery. The biggest drain on a smartphone is the screen, so some apps lower the brightness automatically to protect against this. You can of course do the same thing in Settings, by selecting Display and then looking for the automatic brightness setting. Other power hungry things are apps that over aggressively search for updates, Facebook often being cited as a prime candidate, or Wi-Fi being left on all the time when you’re out and about, as the phone will continually seek out a connection.

Power-saving apps can monitor these connections and behaviours in order to shut down any apps that are being greedy, or switch off Wi-Fi when you are away from your regular haunts. To see exactly what is causing your handset to run out of juice try going to Settings and looking for Battery or Power Management settings, where you should find a breakdown of the most power depleting activities.

It’s worth noting that many of the features that battery-saving, RAM-optimising, task-killing apps boast are all possible without the need for extra software if you're prepared to do the work yourself. You should also investigate the various power-saving modes that your phones might have as standard before you go installing any third-party solutions. 

Do power-saving apps make any difference? 

Like so many things with technology, it really depends on your usage. If you play graphically intensive games on your handset for long periods, then there isn’t really much that a battery saving app is going to do to help you. The same is true for any activity that has the screen on all the time - say watching media content, pouring over the latest news online, or interacting with friends on social media. Where battery saving apps usually earn their crust are the times inbetween you actually using your phone.

So if you find that you leave the house in the morning with a full charge, but a few hours later, without much use, the levels are dropping fast, then either you have a physical problem with your battery (which does happen, especially as a device gets older), or some rogue apps or settings are killing off your power source. In these instances a power saving app should be able to come to your aid, especially if you don’t want to go digging around in the system settings.

As the makeup of each person’s system is different, with the combination of apps, version of operating system, hardware condition, usage habits, and environment all playing a significant part in the puzzle, it’s impossible to guarantee that any particular app will give you a definite improvement. In truth our experience with the various power saving apps we’ve tested has given mixed results. 

On a rooted Android phone we saw excellent performance enhancements with Tasker, as it allowed us to set granular controls for how the device behaved. This transformed it into one that could survive the whole day without recharging, rather than petering out by late afternoon. Conversely a couple of battery saving apps we tested seemed to offer no improvement, and in some cases actually appeared to return less hours of charge in a typical day.

Are task killers, RAM optimisers and battery booster apps worth installing?

Battery saving apps

DU Battery Saver is a very popular Android app, with over five million five-star and over one million four-star reviews on the Google Play store from a total of nearly eight million. Another hugely supported app is Battery Doctor, which has also racked up over five million five-star and one million four star reviews. A common thread with both apps is a noticeable improvement in battery life across a wide range of devices.

Battery saving apps

Digging deeper we found less well known apps such as Battery HD, Avast Battery, and Battery all showing similar ratios of happy users to unhappy ones. It certainly seems in the vast majority of cases employing one of these apps on your phone will provide improved power management for your handset.

RAM Optimisers

The idea of RAM optimisers is to keep your phone memory from getting filled up, and therefore prevent the kind of lag you can sometimes experience when you open, use or move between various apps. Depending on the version of Android you’re running, and the manufacturer skin on top (with Samsung’s TouchWiz being a regular problem in this area), some lag is almost inevitable, but RAM optimisers aim to minimise the drag factor these things create.

Again you can manually control some of the factors involved with lag. Resetting your device regularly can often help, as does keeping an eye on when updates are installed for certain apps, so any change in behaviour can be traced back to that culprit. It’s also a good idea to install new apps one at a time and then looking for any performance hits on your system. If there is, try removing the offender and seeing if you get your speed back.

We’ve seen positive reports on a few different RAM Optimiser apps, with DU Speed Booster & Antivirus proving amazingly popular on the Google Play Store. The app currently has over ten million reviews, and proudly sits with an average score of four and half stars, which is frankly the best advertisement any company could ever ask for. Memory Booster can’t match the amount of reviews, but its smaller audience is again positive about the app’s ability, with the same being true of Memory Booster RAM Optimizer X, and Smart Booster.

So the bottom line is that these apps can make a difference. The best part is that most of the above are available for free, so you can try them for yourself and see whether your phone lasts a few more hours before the power cord beckons.