Did you miss a session from GamesBeat Summit Next 2022? All sessions are now available for viewing in our on-demand library. Click here to start watching.

When I used to write comprehensive iPhone reviews, the most time-consuming tests were some of the most important: battery evaluations to see how long each device would last under real-world conditions. Apple typically made certain guarantees — different numbers for 3G and 4G talk time, internet access, and video playback — but as dedicated reviewers discovered, Apple’s official numbers weren’t always accurate. Sometimes, devices ran significantly longer than promised for some tasks, while shutting down prematurely in others.

I’ll share two behind-the-scenes secrets here: First, conducting these tests fairly and consistently is a truly awful process for reviewers; god bless those who devote days to these measurements, because those who don’t typically rely on those who do. Second, battery life is particularly important at the dawn of any new cellular generation. As of today, 5G connections can under some conditions rapidly drain phone batteries, potentially leaving commuters without sufficient power when they return home from work, and millions of other users — executives, employees, or students alike — with nearly dead batteries before nightfall unless they’re recharged mid day.

Early Android 5G phones anticipated this concern by including larger batteries than their predecessors. But the first 5G iPhones instead went in the opposite direction: The iPhone 12, 12 Pro, and 12 Pro Max actually have smaller batteries than last year’s models, and Apple added an iPhone 12 mini with the same 5G functionality but substantially less battery capacity. It’s no coincidence that Apple has clammed up on cellular battery life claims for iPhones. Having previously shifted to suspiciously soft “similar to last year’s model” battery metrics for prior iPhones, Apple then discontinued publishing cellular battery life measurements on its annually updated Battery Test Information page.

Verizon’s massive 5G marketing campaign has hung on the words “5G built right,” implying superior network performance thanks to faster millimeter wave 5G towers. But the network also depends on 5G devices built right, or at least well enough not to leave users with worries of mid day battery problems. Apple’s choice to go with smaller iPhone batteries this year could be their unexpected Achilles’ heel — a critical performance dimension missed by early reviewers who don’t put in the testing time, even though battery life is really important to actual users. The iPhone 12 mini may be “the world’s smallest, thinnest, lightest, 5G phone,” but it could also have the shortest run time, a potentially huge problem for people expecting a full day of normal use.

I repeatedly used the word “could” because this is a hugely unusual situation in so many ways. People in some countries, notably including the U.S., have at least temporarily cut back on the commuting cycles that traditionally strained phone batteries five days a week. Moreover, 5G isn’t some monolithic evil here, killing every iPhone battery equally; very significant network differences will force some 5G phones to maintain two cellular connections at once and/or use extra power for 5G downloads, while others might actually see lower battery drain with 5G than 4G, at least in some places and situations.

Apple tried to make the issue moot by offering four different devices with three different battery sizes, leaving customers with the decision of how much they’re willing to compromise battery performance. Early battery tests performed by Tom’s Guide covered only the midrange iPhone 12 and iPhone 12 Pro, which notably contain the same battery and have the same 5G hardware. Each model ran for two hours less when using 5G than 4G, yet the two phones delivered different 5G and 4G numbers: The iPhone 12 Pro on T-Mobile’s network ran for over 40 minutes longer on 5G and an hour longer on 4G than the iPhone 12 on AT&T’s network. Whether that’s due to T-Mobile’s use of standalone 5G, which isn’t dependent on a simultaneous 4G connection, is an open and potentially complicated question, offering just one hint as to why Apple didn’t make any 5G battery guarantees to its international customer base.

Even so, you can get a general sense of the models’ battery characteristics from regulatory documents, which have revealed that the iPhone 12 and iPhone 12 Pro have 2,815mAh batteries, roughly 7.5% to 10% lower in energy capacity compared with the 3,110mAh iPhone 11 and 3,046mAh iPhone 11 Pro. Upon release next month, the iPhone 12 mini will have a 2,227mAh battery — a stunning 28% smaller than the iPhone 11’s, and 21% smaller than the iPhone 12’s — while the iPhone 12 Pro Max will have a 3,687mAh cell, down about 7% from the iPhone 11 Pro Max’s 3,969mAh capacity.

When pressed by reporters, Apple generally says that year-to-year battery capacity drops don’t matter for any given iPhone sequel, since there may be efficiency gains elsewhere, such as a new CPU, a better screen, or updated software. But the Tom’s Guide tests suggested a 53-minute 4G shortfall from the iPhone 11 to iPhone 12, versus a one-hour 4G improvement from the iPhone 11 Pro to the iPhone 12 Pro. Network differences could account for these disparities, but so could other factors — a bunch of other factors that would no doubt confound independent testers.

Due to reported manufacturing challenges, we’re around three weeks away from the first iPhone 12 mini and iPhone 12 Pro Max tests, which will reveal just how much less 5G time the mini delivers, and how much of an advantage the Max offers over the smaller Pro. As I noted above, battery life is of particular concern at the dawn of any new cellular generation, and the apologist’s typical suggestion — “just turn 4G off” last decade, “just turn 5G off” this decade — defeats the point of buying new hardware. People have every right to expect that their brand new iPhones will be fully usable and perform as marketed when purchased, and thanks to carrier promises of rapid 5G buildouts, should expect even better performance over time.

If I was purchasing an iPhone now to use for the next three years, as is currently typical for smartphone investments, I would absolutely want to know the 4G and 5G battery performance before making a long-term commitment. Additionally, years of experience have also demonstrated that day one battery life will likely drop to 80% within two years of regular use, possibly leading to performance degradation. In other words, an iPhone that starts with 8 hours of talk time will deliver closer to 6 hours of power in the middle of its lifespan, and even if the performance isn’t throttled, users may consider pricey battery or full device replacements even if their phones are otherwise entirely usable.

In part because of its bigger (but not biggest ever) battery, the gigantic iPhone 12 Pro Max may well wind up being a smarter purchase this year than its Plus- and Max-sized predecessors were in years past, while the small battery in an iPhone 12 mini might make it substantially less wise than it is cute. But only proper testing will let users know for sure. To those of you who are running (and re-running) the 4G and 5G tests this year, I wish you godspeed, as our eyes shall surely be upon you in the weeks ahead.

VentureBeat's mission is to be a digital town square for technical decision-makers to gain knowledge about transformative enterprise technology and transact. Discover our Briefings.