iPhone 15 can limit battery charge to 80%. Does this mean there’s now battery passthrough? - eviltoast

I limit my laptop battery charge to 80% with a third party software tool. Laptops can generally bypass the battery and directly power themselves from the wall.

Does this new 80% battery limit setting imply that the new iPhones are able to do the same? Implication would be less battery wear while docked on a desk/in a car or due to long “AAA” gaming sessions, since it will draw power direct from the wall rather than using the battery as a middleman.

  • hermes2000@infosec.pubOP
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    1 year ago

    You’re right that batteries can’t be both in a “charging” and “discharging” state at the same time. However, a workload drawing 1 A from a battery and a charger supplying 2 A leads to net gain of 1 A, aka “charging”.

    It isn’t both charging and discharging, it’s just in a state of charging, despite the workload it’s performing. Likewise, the battery can provide 2 A while only being charged 1 A, leading to a state of discharging.

    So, a battery can totally power a device while simultaneously being charged, which I believe is how iPhones currently operate. The battery is always in the power path. Willing to be wrong, that’s just my current understanding.

    • FiendishFork@artemis.camp
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      1 year ago

      The battery is not always in the power path. I thought that was how it worked for a long time but got clarification from a writer at anandtech who used to do SoC deep dives. When plugged in the iPhone is directly powered by the wall adapter, excess goes into the battery.