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Comment by bryanlarsen | Hacker News Reader

Wireless is usually a lot slower than plugging it in, so i suspect it'd be better on batteries rather than worse.

But the best way to save your batteries is to not charge to 100%.

I wish there were standard software in Android and iOS to limit charge percentage and battery temperature during charging.

It's ludicrous to me that the default behavior is plugging in your phone to a 30W ludicrously fast charger when you go to bed in the evening, where it then climbs to 100% charge and holds there while you sleep.

I should be able to tell it I'd like it to reach 85% charge as of the time my alarm goes off in the morning, timing that in a way that minimizes battery heating. My laptop, likewise, should be able to sit at 85% when on the docking station, potentially even syncing with my calendar to know when I have to leave and might need more battery or a more rapid charge before a meeting.

> It's ludicrous to me that the default behavior is plugging in your phone to a 30W ludicrously fast charger when you go to bed in the evening, where it then climbs to 100% charge and holds there while you sleep.

Apple already does something similar. It's not configurable beyond on/off but optimized battery charging on MBP, iPhone, and iWatch learns when you're normally awake and holds charging at ~80% overnight until a bit before your normal wakeup time. On MBP it holds at 80% most of the time during the day too if it learns you're rarely running on battery.

On Android this is called Adaptive Charging and has been on my Pixels for several years at this point.

> ludicrously fast charger when you go to bed in the evening

This is why I never charge overnight. Just pop the phone on to charge while I'm having a shower in the morning, or in the evening while I'm having dinner. Those time windows seem enough to keep my phone (Pixel 5) sufficiently charged.

> My laptop, likewise, should be able to sit at 85% when on the docking station

Samsung laptops have/had this exact feature, which they called Battery Life Plus[1]

[1] https://web.archive.org/web/20140101070825/https://www.samsu...

>I wish there were standard software in Android and iOS to limit charge percentage and battery temperature during charging.

Apple has this already, android implementations are more fragmented (not just due to manufacturer but due to charge standard, pmic used, and battery subtypes used). LineageOS has a standard feature they've been working on to provide for charge thresholds but it's not in official builds yet (it's good on the devices I've used it though).

Honestly limiting current is probably bad with modern low resistance cells as temperature is elevated longer. Better to get them saturation charge quickly and stop charging unless you need the extra capacity. Also better to use a low voltage charge standard that doesn't need to drop the voltage in the phone.

All modern major manufacturers throttle the charge current if it breaks thermal limits and have a hard cutoff over a certain value (and down also if it's near or below freezing temps)

Is that the default behavior on iOS? I'm not familiar with the details, but I thought there was logic for optimizing charging, IIRC so that it charges quickly to 80% but then slowly to 100%. And once it hits 100%, it's not like it's constantly drawing power to maintain that level.

You are correct, that's "optimized charging" setting, and it is on by default (but if one is inclined to turn it off for some reason, they can do it in settings).

The Pixel line has adaptive charging, which is active when you have an alarm set, and times the phone to be fully charged by the time the alarm goes off. It's unfortunate this does not seem to be a default behavior for stock Android.

I've had Pixel phones for a while now and I just thought that was a standard Android thing.

It took me a while to learn that I should set a one-shot alarm before I put my phone on the charger.

This feature was not very discoverable, so I also wonder how much unnecessary wear and tear I put on my phone from having rapid charges at bed time before I discovered how to summon the adaptive charge cycle.

samsung phones let you do this exactly.

My Motorola Android (Edge+, Android 12) will charge up to 80% when I plug it in at night and then back-mark against the morning alarm so that it is just getting to 100% when the alarm fires.

Asus Zenfone 9 does the same.

Tbh I don't think its worth even thinking about battery life preservation on phones. The battery can be replaced so cheaply that it makes years of charging anxiety not worth it for a few months longer lifespan.

But the inconvenience of replacing them yourself outweighs the benefit of restoring their battery for many people without much experience. I miss replaceable batteries

But you're usually going to have to replace it anyways if you have your phone for long enough.

Does it usually really matter if you have to replace it after 28 months versus after 32 months? The chance that you'll sell/lose/break your phone in that small window just doesn't seem worth worrying about.

I just take it in to the store, go get something to eat, then pick it up again.

Samsung routines can do exactly this. You can customize it to only charge up to 85% (though no way to set 80% or 90% or something) and then have it not charge until two hours before your alarm, either fast charge or slow charge.

This is why you should keep a non-fast charger next to the bed. Something that can only ever do 5V. If you need to charge quickly, plug in somewhere else.

I have a dell XPS laptop where thia feature is configurable in the BIOS

Is there some way to quickly override it so you get 100% charge ASAP? Or do you have to go into the bios and mess about?

> I should be able to tell it I'd like it to reach 85% charge as of the time my alarm goes off in the morning, timing that in a way that minimizes battery heating.

Isn't this precisely what adaptive charging does?

Pixel devices do this if you have an alarm set. Despite having a Pixel device, this doesn't work for me because I use a separate alarm clock (a daylight one). Instead, I just have an old, slow charger beside my bed.

In that case why not use an old charger that only outputs 5V 1A?

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