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20 Feb 2020

Oppo A9 2020 review: cheap mobile phone aces Which? battery life test

Oppo has produced the longest-lasting phone we've tested for call time, but does it impress as a good all-rounder?

Almost a year after its debut in the UK, Oppo continues to launch affordable smartphones with specs rarely found outside premium models costing upwards of £1,000.

And the £220 A9 is a bit special - it smashed one of our battery tests to become the longest lasting phone we've ever tested for call time.

Those unwilling to fold to the pressure of Samsung and Apple's pricey smartphones should find it refreshing to see cheaper models doing so well in key areas, but does the Oppo tick enough boxes elsewhere to impress overall?

We've taken a deep dive into what you get with the Oppo A9 2020 and some of the other smartphones from this growing brand.

Keen on a smartphone that delivers on battery performance? Read our guide to mobile phones with the best battery life.

Oppo A9 2020 blitzes our battery tests

The Oppo A9 2020 has a massive 5,000mAh battery, the same-size battery you'll find in other budget smartphones such as the Motorola moto g7 power and Realme 5 as well premium models including the Samsung Galaxy S20 Ultra. At present, 5,000mAh is a huge battery for a smartphone in any price range, so it's already impressive to see such a large capacity in such a cheap phone.

When we sent it to our lab, the A9 2020 lived up to expectations. After charging it to full capacity, it made it through a massive 39 hours of call time, making it the longest-lasting smartphone we've ever tested. Its result comes not long after we were blown away by the Oppo RX17 Pro, which got up to 54% after only 15 minutes of charging.

Although its massive battery is likely part of the reason why it pulls off such a stellar performance, battery size is no guarantee. We've tested other smartphones with the same capacity that have lasted 16% less than the A9 2020.

And it's worth pointing out that call time is just one measure by which you can judge a battery - after all, few would expect to spend this long on the phone. This is why we put every smartphone through a range of battery tests to make sure it's worth your money.

How we test smartphone battery performance

We put every smartphone through six distinct battery tests. As well as call time, one of the industry standards for how long a phone's battery lasts, we rate how long a phone lasts browsing the internet, and include a range of charging tests - including a full charge, and a short charge of 15-minutes to simulate those last-minute plug-ins before you leave the house.

Our impartial lab reviews enable us to tell you how good a smartphone's battery is in a range of situations, as well as how long it will last once fully charged.

If you want to find out which models impressed us most for battery life, browse smartphones that have the best battery life.

What else will you get with the Oppo A9 2020?

As important as it is, battery isn't the only thing to consider when buying your next phone. Below, we take a look at some other interesting features of the Oppo A9 2020.


As with a lot of new smartphones, the A9 2020 isn't short on cameras. On the back of the phone, you'll find a quadruple camera array with a 48Mp wide angle lens for capturing wider landscapes, 8Mp ultra-wide angle lens for fitting even more into a picture, 2Mp depth sensor to take better photos in portrait mode and an additional 2Mp lens. Its front camera is a 16Mp wide angle lens. Altogether, this is a more than reasonable package for the price.


It runs on Android 9 but uses ColorOS 6, Oppo's mobile operating system that overlays Android with a user interface custom-made for Oppo devices. Color OS 6 comes with the promise of improved visual designs, better performance for example increased speeds when you're gaming and easier access to your most-used apps.


Although it has a lot of great features, the A9 2020 isn't without weaknesses. It has a very big display, stretching across 6.5 inches but it doesn't have a high resolution for its size. This is only an HD+ resolution (1,600 x 720 pixel) display, which leaves you a bit shortchanged compared to the Full HD+ (2,280 x 1,080) on other affordable phones like the Motorola moto g8 plus (£200) and Nokia 7.2 (£250).

If you want to find out whether this Oppo smartphone is cheerful as well as cheap, head straight to our fully tested Oppo A9 2020 review.

Is Oppo the next big name in the UK smartphone market?

Oppo is a fairly new brand to the UK but has long established itself as a successful electronics manufacturer in Asia, ranking as one of the biggest brands in China. It operates under the same umbrella organisation as OnePlus and emerging brand Realme, which are known for undercutting Samsung and Apple with the price of their smartphones while still offering top-tier specs.

We've tested several models from Oppo and feel it's a brand to take seriously.

  • Oppo Reno 10x Zoom (£460) - If a high-grade camera is your main concern, this is one of very few on the market at its price that offers up to 10x hybrid zoom.
  • Oppo Reno2 (£450) - 6.5-inch Full HD+ display with plenty of cameras to play with as well as heaps of Ram and storage.
  • Oppo RX17 Pro (£250) - Its price isn't the only attractive thing about the RX17 Pro. With a 91.5% screen-to-body ratio and a dual 1,850mAh battery, it has a lot worth looking at.