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swyxtoday at 5:07 PM6 repliesview on HN

> The battery is wearing out a bit, but it started out life with so much runtime that losing a few hours doesn't seem to matter.

this is my exact opposite experience. my M3 Max from 2 years ago now has <2hrs battery life at best. wondering if any experts here can help me figure out what is going on? what should i be expecting?


Replies

varenctoday at 8:26 PM

As others have said, keep the battery in the 80%-30% range. Use the `batt` CLI tool to hard limit your max charge to 80%. Sadly, if you're already down to <2hrs, this might not make sense for you. Also prevent it being exposed to very hot or cold temps (even when not in use)

I type this from an M3 Max 2023 MBP that still has 98% battery health. But admittedly it's only gone through 102 charge cycles in ~2 years.

(use `pmset -g rawbatt` to get cycle count or `system_profiler SPPowerDataType | grep -A3 'Health'` to get health and cycles)

1123581321today at 5:30 PM

What is your maximum capacity in Settings > Battery Health? What processes are running with significant CPU? What's the typical temperature of the laptop according to a stats app? (Temperature is a good proxy for general energy use.)

I'm typing this on an M3 Max; its max battery capacity is 88%. I've got some things running (laptop average temp is 50-55C, fans off), screen is half brightness, and it's projected to go from 90% to 0% in five hours. I don't usually baby it enough to test this, but 8-10 hours should be achievable.

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hmottestadtoday at 7:42 PM

My M3 Max can burn through battery much faster than my M1 Max ever could.

And some apps are really inefficient. New Codex app drains my battery. If you are using Codex I recommend minimizing it, since it’s the UI that uses most power.

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0_____0today at 6:32 PM

Charge habits with batteries make a huge difference. If your use pattern is that once per day, you take the device from 100% to 10%, you put a lot more wear on the battery than if it kind of hovers in the 30%-80% range for example, or if it just hangs out nearish top-of-charge all day when you're at your desk.

Hot take: people should get used to, and expect to, replace device batteries 1 or 2 times during the device lifetime. They're the main limiting factor on portable device longevity, and engineers make all kinds of design tradeoffs just to make that 1 battery that the device ships with last long enough to not annoy users. If we could get people used to taking their device in for a battery once every couple of years, we could dramatically reduce device waste, and also unlock functionality that's hidden behind battery-preserving mechanisms.

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Analemma_today at 6:37 PM

I set Claude loose on my computer and said “why is my battery life so bad?” and it found an always-running audio subsystem kernel extension (Parrot) which didn’t need to be there and was preventing the CPU from going into low-power states. My battery life got noticeably better when I deleted it.

I’m not even sure how it got installed, possibly when I installed Zoom for an interview once but I don’t know. Point is, at least in one case, AI can help track down battery hogs.

speedgoosetoday at 5:31 PM

Also check which apps use the energy.