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Comment by khasan222 | Hacker News Reader

15+ hours of battery life on all of them? I would upgrade my machine for that alone.

Like most PC manufacturers, Lenovo's exaggerates battery life claims. 15 hours is basically if you're idling the machine at minimum brightness with bluetooth and wifi disabled.

For example: Lenovo claims that my 7th gen X1 Carbon has "up to 18.3 hours" of battery life. Typically my laptop uses 5-10 watts. It can go as low as 2.5 watts if I dim the screen to its lowest setting, close all applications, and disable the radios. The battery is 52 watt-hours, so that would be 20 hours of "usage" before it runs out of juice. Really though, I get 5-12 hours depending on what I'm doing.

This is one of the many reasons I keep buying Apple laptops. Their stated battery life claims are usually pretty close or at least reasonable enough. Then I hear all these types of things about PC manufacturers are it just makes paying more for a MacBook a little less frustrating.

Luckily, there are usually third party reviews with accurate battery life claims, at least for more popular laptops (like any ThinkPad). You're right that Apple does do a good job of accurately advertising battery life. On the other hand, since thermals aren't great on most MacBooks, some of Apple's performance statistics are only accurate for the first few minutes until the processor starts to thermal throttle.

how long does it last while asleep? i can close my macbook and come back to it days later and she always boots right up. just curious if the thinkpads are similar

Macs will suspend to RAM and write the RAM state to disk, then use the RTC to wake up 1-3 hours later and power off the RAM to save battery.[1] Resuming from disk takes 5-10 seconds while resuming from RAM takes a second, which is why OSes don't just suspend to disk.

The generic name for this behavior is "hybrid sleep" or "hybrid suspend". It's when the laptop does everything it needs to hibernate (suspend to disk), but then just suspends to RAM.

Almost every laptop is capable of this. The limiting factor is software support. You have to deal with different hardware RTCs, different disk encryption setups, swap partitions vs swap files (and how big they are). It's complicated enough that I decided it wasn't worth configuring, so my laptop loses 3-4% of battery life overnight. That said it is possible on Linux, especially if you use a swap partition instead of a swap file in an encrypted disk.

1. https://support.apple.com/en-us/HT202124

I find the battery life in Lenovo laptops degrading very quickly, comparing to Apple macbooks. I used X1C 4th gen as well as X1 Extreme extensively, and their batteries are pretty close to dead, only delivering ~1-2 hours of work. At the same time, I'm typing this from a 2016 MBP, which is alive and well, batter is good enough still.

Maybe it's just Linux, which I run on Thinkpads. Overall as a system though, the difference is drastic, not in favour of Lenovo.

There has been also complaints that if you have 4K display in Lenovo you are loosing quite much battery life. I haven't seen any definite tests about this though.

Much of the degradation comes from keeping the battery at full charge for long periods of time. Apple improves long-term battery life by lying about battery percentages and only charging once the battery gets below 90-95%. There's even a new option to only charge to 80%.

I get the same behavior in Linux with TLP.[1] I run "tlp setcharge 75 80" and my battery only charges to 80% (and only starts charging if it goes below 75%). If I think I might need power for a longer time, I can run "tlp fullcharge" and wait for it to fully charge.

TLP remembers these settings across reboots so I don't have to think about it.

1. https://linrunner.de/tlp/

My X1C6 is ~2.5 years old, and I still get around 7 hours of battery. Screen is usually quite low brightness as I live in the UK and it's mainly terminal/VSCode/browser.

I used to have a couple of things tweaked like TLP etc but when I reinstalled from scratch with Fedora 32 I didn't do any of that. Still get awesome battery life, i'd definitely buy one of these newer Thinkpads in a year or so.

Lenovo's battery life promises are worthless, I'd confirm with a 3rd party review. My Thinkpad X1 is supposed to have a 9.5+ hour battery life. I have never seen 4, usually 3.5.

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