The iPhone XS and Max do fine on the battery life test, but fall short of one Apple claim
The new iPhone XS Max carries a two-cell L-shaped battery with the largest ever capacity on an iPhone - 3,179 mAh - but don't get too excited. Judging from our benchmark test results, and Apple's official stats, the company's battery life champ is shaping up to be the iPhone XR due to its lower display resolution.
A couple of teardowns later, we now know the exact 2658 mAh capacity of the battery pack in the iPhone XS, too, and it is slightly smaller than the 2716 mAh pack in the iPhone X. Moreover, the iPhone XS is housing a unique single-cell L-shaped battery.
The L-shaped one in the iPhone X is actually two individual cells with a separator between, but this thing is bent out of shape around a corner, and packed neatly together. It's still a tad smaller than the unit in the X, though, and we'll see how this corner-ed design performs in the long run.
Apple's official iPhone XS Max vs XS vs X battery life stats
As you can see in Apple's official stats above, the iPhone XS Max should score better battery endurance than the XS, which in its turn should score about the same as the iPhone X before it. We found these claims to largely hold true - the iPhone XS Max managed to keep the lights on for 9 hours and 34 minutes in our grueling test that mimics pretty well what you would get as screen-on time in real life, and is even a bit optimistic under heavy usage scenarios. The iPhone XS scored about an hour less - 8 hours and 37 minutes, almost as long as the iPhone X lasted, so we'll call it even.
Apple's iPhone XS Max vs XS vs X battery life stats held true in our test, but not the claims vs iPhone 8 Plus
Where Apple's claims fell apart, however, is comparing the official battery life stats of its new handsets against its reigning marathon runner the iPhone 8 Plus. That one is still sitting at the top of our iPhone endurance chart with 10 hours and 35 minutes, or, the exact opposite of the XS Max advantage that Apple lists against it.
Granted, our script simulates mixed usage on 200 nits of screen brightness, rather than simply measure video playback or browsing separately as Apple does, but we were still a bit miffed to find this result.
As far as the other Android flagships, they aren't far behind despite their higher display resolutions, as they also have larger battery packs on average. When that's not the case, though, our own power efficiency comparison found out that the higher a phone display's resolution, the shorter the battery life if we average out their capacities.
The XS has a unique single-cell L-shaped battery
We tested them with the stock Apple brick that comes in the box, and found out that you will need the whopping three hours and a half to top the "largest ever battery in an iPhone." The XS is also no joy in that respect, with a bit over three hours.
This is borderline criminal compared to most Androids whose fast chargers come in the box and don't require you shell out $68 extra for the privilege. Oh, well, next year is not an "S" upgrade, so something has to be left for the 2019 boxes, too.
Long story short, if you want the best battery life on an iPhone, you'd have to wait for the XR. It has better endurance stats than the XS Max with its bigger pack, and the XR's "low-res" 828p display is the reason for what will likely turn out to be the best ever battery life on an iPhone, according to Apple's own specs sheet.
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