Battery Life

The Zenfone 8 features a contemporary 4000mAh battery, which considering the size and 169g weight of the phone is actually quite respectable and competes well with other alternatives in the market.

The features that might impact the battery life of the phone are the Snapdragon 888 SoC, less efficient than its predecessor, as well as the 120Hz display which lacks any more advanced power management. The latter aspect of the phone can be quite negative – while the 60Hz mode of the phone has an underperforming base power consumption of 615mW, the 120Hz mode raises this to a rather eye-watering 783mW on a full black screen at minimum brightness.

Anecdotally speaking, I’ve seen vast power regressions on almost all Snapdragon 888 flagship devices this year, all except for Samsung’s S21 Ultra. The Mi 11, Mi 11 Ultra, OnePlus 9 Pro, ROG Phone 5 all exhibit quite bad base power behaviour, and the only difference to the S21 series is that Samsung employs Maxim PMICs and Broadcom WiFi solutions rather than Qualcomm’s own chips. I don’t know if there’s a correlation there or not, but the Zenfone 8 shows similar lacklustre efficiency.

Web Browsing Battery Life 2016 (WiFi)

In the web-browsing test in Auto mode which switches to 90Hz inside of the browser, the Zenfone 8 tracks rather closely to the Zenfone 7. The predecessor has a 25% larger battery, but also has a much larger display. The contemporary comparison to make is the smaller Galaxy S21 which lands ahead of the ZF8 even though it runs at 120Hz mode, and far ahead at 60Hz.

I’ll be updating the article with fixed 120Hz and 60Hz results for the ZF8 in the coming days.

PCMark Work 2.0 - Battery Life 

As noted in the performance section, “Auto” mode actually fixes itself to 60Hz in various applications, such as PCMark. The ZF8 here in its best-case scenario lands actually quite well in the relative positioning, meaning battery life in this mode is relatively competitive.

Again, I’ll be completing the result set with other refresh rate modes in the comings days.

Generally speaking, the Zenfone 8 finds itself in a tough situation when it comes to battery life. The 90Hz and 120Hz modes are really inefficient due to extremely lacklustre base power consumption behaviours. If you were to use your phone at very high brightness levels, the luminance power would vastly overcome that disadvantage and one probably wouldn’t notice the deficit as much, but at lower brightness levels, the phone would last much less than comparative devices.

The conundrum with this situation is that while 60Hz seems to be efficient for the Zenfone 8, it’s also not an as quite good experience when it comes to performance and responsiveness. So either you’ll have to deal with a responsive and inefficient device, or with an adequate battery life but sluggish feeling phone.

GPU Performance Camera - First Impressions


View All Comments

  • drajitshnew - Thursday, May 13, 2021 - link

    I do not understand -- they should be adding micro SD express. Reply
  • thejaredhuang - Wednesday, May 12, 2021 - link

    So I've seen the picture of the 4000mAh battery on 2 different sites, it looks like its easily replaceable once the back cover is off, Andrei do you have any info on how easy it is to remove the back cover? Reply
  • Unashamed_unoriginal_username_x86 - Wednesday, May 12, 2021 - link

    The paragraph on the last page starting with "As we always say" is duplicated Reply
  • Wereweeb - Wednesday, May 12, 2021 - link

    I actually quite like this one. Not gaudy, not cringy, not exaggerated, just an all-around solid and compact smartphone. The camera bump does look misaligned, and the chrome ring around the selfie cam is just one of the dumbest things I've ever seen; but otherwise, if I needed to daily carry a SD 888, this would be the phone I'd buy. Reply
  • Silver5urfer - Wednesday, May 12, 2021 - link

    No 3.5mm jack on the Flip and no SD slot on the both phones, bonus is get a hole in cheaper version. Well this is going to be a skip. Sony Xperia 1 Mark III is still the king on the smartphones right now, king in price also unfortunately.

    SD slot is not about storage, it's about having things right near your fingertips in the case of any emergency - Phone cracked / Phone busted up need to send to factory / Immediately need to get data to a PC / any private data. That is not possible with any solution, Cloud is not a solution at all as it needs constant Internet access and background data usage PLUS it's going to a blackbox security system putting all your data behind a ToS and Privacy Corporate Policy.
  • flyingpants265 - Wednesday, May 12, 2021 - link

    You'll never get what you need by relying on a private corporation - if you want actual utility, you'll need a government subsidy or non-profit or something. The population is never going to "learn to make the right choices", that day is never coming.

    What's needed is several different models of fully-featured Linux phones. Won't happen.
  • ozon - Friday, May 14, 2021 - link

    There's microSD slot on the 8 Flip. Saw it listed on the Asus page. Reply
  • nicolaim - Thursday, May 13, 2021 - link

    No wireless charging: lame. Reply
  • JfromImaginstuff - Thursday, May 13, 2021 - link

    You do realise that wireless charging is still very inefficient Reply
  • ads295 - Thursday, May 13, 2021 - link

    I think there should be a law forcing it to be named "wired wireless charging" until we can transmit at least 5W of power over a distance of 1 metre. Reply

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