Does the power saving mode on the Samsung Galaxy S5 work?

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Uncharged phones are banned on flights between the UK and US. But can the battery saving mode on some handsets keep your battery going a little longer?

Samsung made plenty of noise about the ultra power saving mode on its Samsung Galaxy S5 when the flagship phone launched. It’s no wonder. While heart rate monitors and fingerprint scanners may grab the headlines, boosting battery life is something that users genuinely care about.

Batteries have been getting bigger for the last couple of years but the power saving mode on the S5 offers something more. It promises to eke out more life from the last 10% of your battery by turning off certain features and even flipping your home screen to black and white.

Of course power saving modes aren’t new. The difference is they have become more powerful and more customisable. But do they work? We sent the Samsung Galaxy S5, HTC One M8 and Sony Xperia Z2 to our lab to put their power saving modes through a real life test. You can see the results below

Phone reviews – read our verdict on all the latest handsets

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More battery, fewer missed calls

Good news all around. The S5 added an extra four hours on to the last 10% of battery life when in power saving mode, as did the Xperia Z2, while the HTC One M8 went one better with five hours.

These are meaningful differences that should help you make that crucial call or receive that important text message before your battery runs out of juice.

How we tested power saving modes

Since there’s no standard for this type of test, Which? decided to conduct a one-off comparison to identify how much benefit the power saving modes offer. This test is a snapshot in time and actual battery life can vary depending on your usage.

Which? tested each phone after running down the battery to 10% life. Two battery tests per phone were conducted, one with the power saving mode switched on (to the default setting) and one with it turned off. The test comprised a mix of mostly standby time plus some calls and web browsing.

We’ve listed below the power saving mode we used during the test and the features that were affected:

Sony Xperia Z2 – Low battery mode

This mode can be programmed to be activated once the battery gets to a preset level. You can select the features that are affected but the default settings (which includes turning off mobile web browsing) are as follows:

  • mobile data off
  • reduced screen brightness
  • faster screen timeout
  • auto sync off
  • Bluetooth & wi-fi off
  • GPS off
  • vibrate on touch off

HTC One M8 – Extreme power saving mode

This puts the device into a basic menu mode and can be programmed to be activated once the battery levels gets to a preset level. The mode does the following:

  • reduces CPU usage
  • reduces screen brightness
  • turns off vibration feedback
  • turns off the data connection when the screen is inactive
  • allows only essential apps to run
  • turns off the pedometer

Samsung Galaxy S5 – Ultra power saving mode

When using the ultra power saving mode, the S5’s display turns to black and grey and the functions listed below are either turned off or or run at a reduced rate:

  • turns off background data when screen is off
  • turns off wi-fi and Bluetooth
  • turns off GPS
  • turns off vibration feedback
  • restricts usage to essential applications and those selected by you

How important is battery life to you when buying a phone? And what do you make of the HTC One M8’s performance? Let us know in the comments section below.

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14 replies

  1. Pretty meaningless. When all that functionality
    is switched off, a smartphone is hardly smart.
    You d have been better measuring the current
    drain on each device when the functionality
    is broadly similar.
    Or done a review of the wide variety of back up
    batteries like the mophi available for Apple.
    To my mind these are the only way forward.

  2. Agree with Gerry Woolf. I use a Nokia 5310 purely for most of my phone calls and it’s battery life is huge. I use my Galaxy S5 for everything else and maybe a few phone calls. “Dumbing down” a smartphone just to save power rather defeats the object of having it. Manufacturers MUST press battery manufacturers for major battery improvements. Since developers released the Lithium-Ion Polymer battery in 1997, development to date seems to have slowed right down. Time for a new breakthrough!

  3. I agree with the comments by Gerry & Syxie. The saver modes are not going to be used by most as they are really just very crude versions of apps already available in the Play Store.

    In addition to looking at back-up batteries as Gerry suggests, a more useful review would be one that compared battery saving apps, like Green Power and Juice Defender. These have been available in the Google Play store for more than three years, are widely used and have been refined over time.

  4. Many of these features can be manually configured, if we take the time to do it, so that battery life is extended without the loss of the functions that make your phone smart. Leave wifi off if you are out and about. It expends power trying to find hotspots that are often out of range. Don’t use GPS unless you are using maps or MUST have specific location data. The same goes for Bluetooth. it is an unnecessary drain if you are not in range of the paired device. It requires more effort but you can get a working day out of your device.

    Screen quality and functionality have increased hugely and this has come at a price.

    The time has gone where you could measure battery life in days but we could do with something that would last all day (24 hours) rather then 6. Batteries HAVE become bigger but they have reached their technical limits. We need self charging phones such as solar(pv) or self-winding (motion detection).

  5. My Lumia 1020 switches to power saving at a predefined remaining % similar to these. While I too would like full functionality for longer I do like the power saving to kick in, especially when I may not have noticed battery getting low, keeping my phone live for any urgent call or texts. Running out completely it’s a disaster.

  6. I hate the idea of having a smart phone but not being able to use it as it was meant to be used.
    That’s why I always pick my phone by the ability to replace the battery.
    That’s where to me samsung phones win hands down, you can carry a spare fully charged battery and just swap out when you need to, and then over night charge the phone and spare battery (in its seperate charger) ready for the next day. No need to switch everything off, or carry cables and look for a socket, just a spare battery that fits in all pockets, that you won’t notice is there until you need it.

  7. Agree with all the others. Weird seeing as the m8 acutally has a normal “power saving mode” as well as the extreme one which is only supposed to be when you’re desperately out of battery.. WEIRD!!

  8. I have to say that I agree with all of the comments. I recently purchased a Samsung S4. I am hardly going to get rid of it for quite a while. It would make more sence, to me to test out the currently available “battery savers” available, that is, I suggest of importance. To avoid the normal battery problems I have purchased a VERY big battery. Unfortunately it has turned my S4 into something I would not like to drop on my toes! The thing is it works, my phone now will act as a phone and play MP3 audio books for 3 or 4 days between charges.

  9. I disagree. Here’s why.

    Of course, ideally we want longer battery life. And we have seen incremental improvements in battery life in recent years. These haven’t been substantial because manufacturers are coming up against the limitations of the technology. That will and is changing. But in the meantime these battery modes give users the option of squeezing a good bit more life out of the critical last 10% of your battery – being able to take that call you’re waiting for or stay in touch while you’re travelling.

    I think Samsung and other manufacturers – quite rightly – take a fair bit of flak for designing features nobody wants, but poor battery life is something that is a genuine user concern. These battery saving modes don’t fix that problem but they can help.

  10. I keep a spare battery for my Galaxy Note 2. Only cost £10 and can be swapped in 30 seconds. Rarely have to use it in normal use as the Note 2 has excellent battery life but handy if i am away from a power source for days at a time. Would never buy a phone that des not have a replaceable battery.

  11. People forget a phone’s direct purposes include: phone, text (even though ineffective), calculator, internet, compass, notes, accelerometer, barometer, & camera. Phones have too many options, games, & ridiculousness non-sense (facebook & every other social media). That fact that phone’s can’t survive 1 lousy day without hugging the charging cord is meaningless. What’s the point of a communication & survival device if it can’t last. Ultra-Power Saving Mode isn’t meaningless. It’s the route that phone’s need to take. Let’s hope it’s not forgotten because the mainstream facebook addicts can’t understand it’s highly effective functionality.

  12. Hi
    The Galaxy S5 is, by a margin, the best of the current smartphones. In terms of user friendliness, screen quality it is the equal of iPhone 5 and it wins handsdown by virtue of it being water resistant and having outstanding battery life.
    To give you an idea of the latter, I use my phone for golf gps. The Apple product, with everything else turned off, uses approximately 65% of its battery in a round whereas the Samsung uses around 30%.
    And don’t get me started about the effects of water within a country mile of an iPhone – they are toast. Galaxy shrugs off heavy rain.
    Love my MacBook and my iMac, but their phones are becoming unfit for purpose and are relying purely on Apple’s reputation and marketing.
    John Fitzgerald

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