Best phone battery life: does the Samsung S9 Plus have the biggest and best battery?

No matter how you use your smartphone, it's likely that battery life is something you prize highly – having a phone that can keep on going to the end of the day, through all the calling, messaging, web browsing, video watching and whatever else you need to do.

Here we'll help you pick out the very best phones for battery life by highlighting some of the handsets with the biggest batteries currently on the market. You might have to pay a little extra and put up with some extra weight in return, but that's not a bad trade off.

• The very best smartphones you can buy right now
• The top smartphones of 2018 for people shopping on a budget

Before diving in, it's worth mentioning that battery size doesn't always equate to battery life: it also depends on the apps you're running, the size of the display, how the hardware has been optimised, and so on. But having a huge battery to fall back on certainly helps.

Samsung tries its best to keep its flagship phones as slim and svelte as possible, which usually runs counter to the idea of having a bulky battery in there, but the Samsung Galaxy S9 Plus pulls off the trick – there's a hefty 3,500mAh battery inside the bigger of the S9 phones, which offers an even higher capacity than the battery used in the Galaxy Note 8.

Of course the Galaxy S9 Plus is about much more than just the battery: it's got that fantastic-looking 6.2-inch Infinity Display screen, the best internal specs you can get in 2018, and a dual-lens rear camera that excels in just about every scenario. 

Hoever, as we’ll see, the S9 Plus is not the phone champion when it comes to battery girth...

The big battery of the Asus Zenfone Max Plus has been pushed as one of the phone's key selling points ever since it was first unveiled at the CES 2018 trade show – there's a 4,130mAh battery tucked away inside this Android handset, which apparently equates to 13 hours of video watching or 21 hours of web browsing (though your mileage may vary).

Aside from that humongous battery, the Asus Zenfone Max Plus brings with it an elongated 5.7-inch screen with a 2160 x 1080 pixel resolution, a 1.5Ghz octa-core processor, 3GB or 4GB of RAM, and 64GB of storage. Around the back there's a very capable dual-lens camera, with the secondary wide angle lens giving you more options for your shots.

Mobile gaming is very much the focus of the Razer Phone, and if you want to run demanding games for hours on end – complete with rapidly changing visuals and loud audio – you need a battery to cope. The Razer Phone comes fitted with a 4,000mAh battery, which puts it comfortably in the top tier of smartphones based on battery capacity.

You get a bright 5.7-inch, 2560 x 1440 pixel resolution screen with the Razer Phone, capable of hitting a refresh rate of 120Hz. Also to the phone's credit at the large stereo speakers, the rapid Snapdragon 835 chipset, and the generous 8GB of RAM. Whether or not you're going to use this for gaming, the Razer Phone is eye-catching for many reasons.

Besides everything else it's got going for it – that crisp 6-inch, 2560 x 1440 pixel screen, the Snapdragon 835 processor, the 4GB of RAM, and the Pixel take on Android – the Pixel 2 XL from Google also has a 3,520mAh battery, which is going to get you through a lot of phone use (even if the OLED display is also likely to suck up plenty of juice at the same time).

Besides those excellent specs and that big battery, the Pixel 2 XL also comes with an excellent rear camera. It might only be a single 12MP lens affair, but thanks to the software processing algorithms Google has perfected, you can get some great-looking shots even in the darkest of conditions (and with a Pixel all your Google Photos storage is free as well).

If a big battery is your primary concern in a smartphone, to the exclusion of just about everything else, consider the newest item in our list: the recently unveiled Moto E5 Plus, which like its 2017 predecessor comes packing a gigantic 5,000mAh capacity battery. That's a lot of juice, and should get you through two days of use according to Motorola.

The battery life claim is helped by the phone's modest specs. The screen measures 6 inches but has a lower-than-normal 720p resolution, while the chipset inside is a mid-range Snapdragon 425, and the rear-facing camera is a single-lens 12MP affair. The phone is going on sale from now, and you can pick it up for a bargain basement price.

A lot of flagship phones sacrifice a little bit of battery capacity in return for a more streamlined, lighter design, but not so the Huawei P20 Pro. As well as packing in a 4,000mAh-capacity battery, it also offers top-of-the-range smartphone specs, and is the first phone we've seen to feature a triple-lens camera setup around the back.

That lets you perform some rather funky tricks with the camera, and we were impressed with the phone when we had it in for testing. As well as the camera and the battery, the phone boasts a speedy (and AI optimised) Kirin 970 chipset, a full 6GB of RAM, and 128GB of on-board storage – though you will have to pay flagship prices for those flagship specs.

• The best smartphone battery cases for iPhone and Android