While cameras, displays and processors improve year-on-year, one aspect of smartphones hasn’t changed in years: battery life. Gone are the days where you can charge your phone once a week and not have to worry about it running out of battery – or are they? While an iPhone might not last all week on a single charge, there are some smartphones out there that might.

What are the important features to look out for when looking for a phone with great battery life? While it’s not the only important feature, the higher the capacity of the battery, the longer the battery should last. Anything over around 3,500mAh should last longer than a day, although there are exceptions to that rule.

The features of a smartphone can have a negative effect on battery life, no matter the capacity. For example, a smartphone with a QHD display will run out of battery faster than the equivalent smartphone with a Full HD display because it’s powering more pixels.

With that being said, recent smartphones are much more power efficient than those released a few years ago and should use less juice to perform the same tasks.

Along with a high-capacity battery, some form of quick charging technology is also recommended. While it’s a feature of many 2017 Android smartphones, it doesn’t come as standard and is definitely worth checking – especially when some smartphones in our roundup are over 5,000mAh.

Quick Charging offers exactly that; fast charging. While you may not notice the benefit when charging a smartphone with a smaller battery, it can take hours to fully charge a smartphone with a large battery when it doesn’t offer any form of quick charging tech.  

Of course, buying a smartphone with a large battery isn't the only option; you could also invest in a power bank, or try to improve the battery life of your current smartphone instead. 

Based on the above, we’ve scoured the internet and found a selection of smartphones available in 2017 that feature great battery life. Disclaimer: we haven’t tested all smartphones featured below, but instead based our decision on the specs and claimed battery life.

Samsung Galaxy S8 Plus

Samsung Galaxy S8 Plus
  • RRP: £779, US$899

The latest in Samsung’s flagship Galaxy range, the S8 Plus boasts impressive battery life. This is down to a combination of power-efficient hardware, software enhancements and of course, a large battery to power that 6.2in curved display.

The Galaxy S8 Plus features a 3,500mAh battery (500mAh more than the standard S8) with many reports claiming it offers around 18 hours of use on a single charge. The S8 Plus also features quick charging technology that’ll get you untethered from the wall faster than other smartphones.

Moto Z Play

Moto Z Play
  • RRP: £379.99, US$449.99

Lenovo’s 2016 Moto Z Play, along with an almost indestructible display also offers impressive battery life. In fact, Lenovo claims that the smartphone will last two days on a single charge, thanks to the huge 3510mAh non-removable battery.

Much like other smartphones in this roundup, the Moto Z Play also features ‘TurboPower’ charging technology that offers nine hours of battery life in 15 minutes. During our testing, we found that the Moto Z Play charged from 12- to 25 percent in 15 minutes.

Huawei Mate 9

Huawei Mate 9
  • RRP: £599.99, US$599.99

Huawei’s premium 5.9in smartphone is a beast when it comes to battery life. Why? It’s mainly to a whopping 4,000mAh battery (one of the biggest in its class), which Huawei claims should get the average user through two days of use without requiring a charge.

That’s helped along by Machine Learning algorithms part of EMUI 5.0 that help the smartphone run more efficiently over time, along with Huawei’s own Kirin 960 CPU that isn’t just fast but also power efficient, thanks to the 16nm manufacturing process.  

And to top it off, the Huawei Mate 9 also features Huawei’s own SuperCharge technology. The company claims it’s one of the fastest charging systems in the world, and can provide a day’s use with 20 minutes of charge.

OnePlus 3T

OnePlus 3T
  • RRP: £399, US$439

Considering the sub-£400 price tag, the OnePlus 3T offers high-end specs including a Snapdragon 821 processor and a whopping 6GB of RAM – and it doesn’t stop there either. The 5.5in smartphone also boasts a huge 3,400mAh battery that should provide users with around a day of use on a single charge.

In fact, our review states that some users could even see 1.5 days’ worth of use on a single charge.  

Of course, the OnePlus 3T also boasts the company’s own Dash Charge technology that can charge the phone from 0-60 percent in only 30 minutes. Impressive stuff.

Apple iPhone 7 Plus

Apple iPhone 7 Plus
  • RRP: £719 (32GB); £819 (128GB); £919 (256GB), US$769 (32GB); $869 (128GB); $969 (256GB)

While Apple’s iPhone can’t quite compete with the large-capacity batteries featured in Android smartphones, it’s probably worth mentioning at least one for fans of iOS. Our choice is the iPhone 7 Plus: it features a 2,900mAh battery (compared to 1960mAh in the iPhone 7) that users claim can comfortably get them through a day without requiring a top-up.

Apple’s iOS operating system also has a built-in battery saving mode that, when activated, saves battery power without a noticeable effect on performance. While users are prompted to turn it on at 20 percent, some users keep it on indefinitely for an iPhone that lasts much longer.

It’s worth mentioning that the iPhone 7 Plus (nor any other iPhone) doesn’t feature any kind of quick charging technology, meaning it can take a while to charge once the battery is completely dead.

Asus Zenfone Max

Asus Zenfone Max
  • RRP: £160

Okay, brace yourselves. The Asus Zenfone Max has one of the largest battery capacities of all smartphones in our roundup at an eye-watering 5,000mAh. When coupled with a slightly underwhelming (but low-power) 720p display and a Snapdragon 410 processor, you’re left with a smartphone that should just keep on going. And going. And going.

Sure, the mid-range specs aren’t as exciting as the Galaxy S8 Plus or Huawei Mate 9, but if you want a phone that’ll last then the Zenfone Max should do the job.

Lenovo P2

Lenovo P2
  • RRP: £199.99

The Asus Zenfone Max is only trumped by the Lenovo P2, a budget smartphone with an incredible 5,100mAh non-removable battery. The battery life is the headline feature of the phone, with Lenovo claiming that it can last not one, not two but three days on a single charge. In fact, we noted in our review that even after three days of standard use, it still had a little bit of charge left.

It is also equipped with fast charging via Micro-USB and can offer around 10 percent in 15 minutes, the equivalent to around nine hours of usage.

Nokia 3310

Nokia 3310
  • RRP: £49

Of course, if you can live without the ‘smart’ capabilities of a smartphone then the 2017 Nokia 3310 may be a good alternative. Sure, it might only have a 2.4in TIT display and no GPS or a front facing camera, but the battery is said to last around a month on a single charge. An entire month.

This is due to the basic nature of the phone – it only operates on the GSM network and as it doesn’t have to power features like GPS, it can make the 1,200mAh battery last that little bit longer than the competition.