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

  • itsjustaprankbro - Wednesday, May 19, 2021 - link

    Yeah, wife also uses S10e. Thought about this phone but she loves wireless charging. There is also the Xiaomi Mi 11 Lite 5G, but also no wireless charging (and no OIS on that one). Sony's compact phones also lack wireless charging, despite costing twice as much. There is only the S20-S21, but those phones have some utterly horrible battery life and performance (minus the Snapdragon models). So I guess, the S10e will have to serve a few more years. Reply
  • BedfordTim - Thursday, May 13, 2021 - link

    It was one of the many annoyances of my Nokia 9. I can't imagine going back to 128GB. Reply
  • yetanotherhuman - Saturday, May 15, 2021 - link

    I use a phone with 64GB and don't give a shit. I guess we're all different. Reply
  • itsjustaprankbro - Wednesday, May 19, 2021 - link

    Silliest comment of the year. If not the decade. Yes, Samsung made 512GB edition of the Note 9. Released 1TB edition of the S10+. And? It keeps releasing the S20 Ultra, S20, S20+, S21 Ultra, S21 and other phones with a measly 128gb storage ONLY. And there is NO dedicated microSD slot (like on the Zenfone 6-7-8), just a hybrid SIM slot.

    If anything, Samsung is pathetic. Yes, I am salty about their decisions because a new S21 costs an insane amount of cash and it has no storage?
  • quiksilvr - Wednesday, May 12, 2021 - link

    Uh, that plastic gasket piece between the metal frame and display is essential for durability. It is actually something you are supposed to have. Removing it is the cheap move, not the more expensive move. Reply
  • Wereweeb - Wednesday, May 12, 2021 - link

    Tell that to people who think a smartphone's function is to look pretty in your hand. Reply
  • eastcoast_pete - Wednesday, May 12, 2021 - link

    The problem with your statement is that it's true and thus makes sense 🙂; unfortunately, many people prefer looks over function. Reply
  • arashi - Thursday, May 13, 2021 - link

    All iPhones are cheap phones to Andrei maybe. ;) Reply
  • eastcoast_pete - Wednesday, May 12, 2021 - link

    Thanks Andrei! I don't like that they dropped the microSD slot; there are fewer and fewer phones in the upper middle and flagship range that have those. Regarding the battery life, maybe ASUS could come out with a Zenphone 8 Lite with everything like this (plus mSD slot, please) , but with the SD 780; plenty fast, much easier on power draw Reply
  • Kangal - Thursday, May 13, 2021 - link

    I agree 100%.
    They can't compete when it comes to Software Updates, or Camera Quality, or Customer Service. So there's no point for them to compete in the Luxury/Flagship category.

    They should've just made ONE variant: QSD 780, 8GB RAM, 256GB storage, and decreased the price by $100 to compete in the High-end category instead. Don't make different RAM/Storage options, or different 3G/4G/5G radio variants... that's a waste of money.

    Their winning strategy against those cheaper Chinese competitors? Just do a clean Stock AndroidOS, have unlockable bootloader, and include the basic features. Basic features are: 3.5mm Jack, microSD, IrDa. Also great features are Front-firing stereo loudspeakers, Flat Display, IP68 protection or User Removable Battery. I know I'd buy it, even with the QSD 780G, as that is actually a Flagship-level Processor, unlike QSD 845 or QSD 768G (or lower).

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