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How is the state of linux power saving (i.e., mobile battery life) in 2021? Last time I checked you could expect to get almost 2x the battery life on equivalen

How is the state of linux power saving (i.e., mobile battery life) in 2021? Last time I checked you could expect to get almost 2x the battery life on equivalent hardware with Windows or Mac OS.

TobTobXX 5y ago
Can't comment on mobile, but I've set my laptop to sleep after 10min of inactivity and 3min after lid close and it lasts the whole day (4.1Ah). I'm not using it for 8h straight, but rather a combined 3h or sth probably but with this aggressive sleep settings it easily stretches some 8h and I don't feel afraid of it just going out at the end of the day.
abdullahkhalids 5y ago
When I bought my T440s in 2013 (8 years ago now), I could push it to 18 hours with wifi off. And could get 10 hours plus with wifi. I seriously doubt Windows or Mac OS would have gotten much more juice out of it.
- ryantgtg 5y ago
  I currently use a T440S, with Arch Linux, and fairly recently replaced batteries. I feel like I only get 5 hours or so. Although if I’m on my work computer, with my T440s open next to me and I’m lightly using it throughout the day then it easily lasts all day, with like 30-40% remaining at the end of the workday. My biggest beef is that the replacement batteries these days seem bad - even brand new Lenovo brand ones degrade really fast. My assumption is that they’re not being manufactured anymore, and so a “new” battery is actually new old stock and has been sitting around for years. I am tempted to upgrade to a newer laptop.
  - sudosysgen 5y ago
    New batteries won't lose capacity over time. A lot of "new" batteries are just knockoffs, but there's no way of knowing without opening them. If you want good aftermarket batteries, KingSener has a solid reputation. Only go for aftermarket batteries that are upfront about being aftermarket and are open about the cells they use and well reviewed, or for sealed Lenovo batteries in original packaging. I recently bought a brand new, sealed 72Wh original battery. It sat sealed for so long the batteries went down below 3.1V per cell and the pack locked itself. Looking at the self discharge curves I'd expect this to be the case for any actually new battery. To make it work I had to open the battery and use a specialized charger to give it 0.1A of current until it got to 3.3V per cell, and I then programmed it to charge at 6A, after which the battery pack decided to start up.
    - ryantgtg 5y ago
      Thanks. I’ll try that brand. I buy mine from Encompass, the official seller of Lenovo batteries. So they shouldn’t be knockoffs, nor unsealed. But, one battery went from 90% health down to 30% in the course of six months. And they’re not cheap!
ohazi 5y ago
Generally pretty good. With tlp and a 5.10ish kernel, my T480 handles light web browsing at 3-5 W depending on display brightness (wqhd display). Heavier websites, high-res video decoding, etc. will bring it up to 7-10 W. Maybe 20 W when compiling something, or when attempting to use the (worthless) Nvidia GPU (which I leave powered down most of the time). It has a dual battery setup with a 24 Wh internal battery and a 72 Wh external battery (I use the bulbous 6-cell, but you can get a thinner one if you prefer), so even when setting the charge stop thresholds at 80% to preserve cell lifetime, the computer easily lasts all day on battery. That being said, it would be easy to find a random laptop that either idles at something stupid or that can't go to sleep properly because of just one wacky peripheral, making Linux power management seem bad. Half the battle is picking the right starting point (e.g. a Thinkpad), and then setting everything up so you can actually measure the power in all of the different states so that you can actually confirm that your setup works properly before relying on it and ending up disappointed at the airport.
- robmsmt 5y ago
  if you could point to how you configured your power management that would be great
  - smoldesu 5y ago
    "sudo tlp start" :)
    - ohazi 5y ago
      Start with this. If there are peripherals you don't use (something as small as a Bluetooth adapter or as large as a GPU), figure out how to power them down, and get the computer to put them in that state by default. On ThinkPads (and probably on others), you can monitor the instantaneous power consumption by poking around in: /sys/class/power_supply/* There are widgets that can monitor this for you and alert you if anything seems amiss, but I just have a script that puts some text and symbols in my menu bar: https://github.com/ohazi/dotfiles/blob/master/bin/battery.sh https://github.com/ohazi/dotfiles/blob/master/bin/battery.sh You can use this to confirm that (for example) your wifi card is actually powering down when you ask it to.
sudosysgen 5y ago
Nowadays Windows consumes more power than Arch Linux with KDE given a processor underclock and power saving tweaks. On my X250 with a 72Wh external battery I can get 14h of battery life without sacrificing much of anything.

How is the state of linux power saving (i.e., mobile battery life) in 2021? Last time I checked you could expect to get almost 2x the battery life on equivalent hardware with Windows or Mac OS.

TobTobXX 5y ago

Can't comment on mobile, but I've set my laptop to sleep after 10min of inactivity and 3min after lid close and it lasts the whole day (4.1Ah). I'm not using it for 8h straight, but rather a combined 3h or sth probably but with this aggressive sleep settings it easily stretches some 8h and I don't feel afraid of it just going out at the end of the day.

abdullahkhalids 5y ago

When I bought my T440s in 2013 (8 years ago now), I could push it to 18 hours with wifi off. And could get 10 hours plus with wifi. I seriously doubt Windows or Mac OS would have gotten much more juice out of it.

ryantgtg 5y ago
I currently use a T440S, with Arch Linux, and fairly recently replaced batteries. I feel like I only get 5 hours or so. Although if I’m on my work computer, with my T440s open next to me and I’m lightly using it throughout the day then it easily lasts all day, with like 30-40% remaining at the end of the workday. My biggest beef is that the replacement batteries these days seem bad - even brand new Lenovo brand ones degrade really fast. My assumption is that they’re not being manufactured anymore, and so a “new” battery is actually new old stock and has been sitting around for years. I am tempted to upgrade to a newer laptop.
- sudosysgen 5y ago
  New batteries won't lose capacity over time. A lot of "new" batteries are just knockoffs, but there's no way of knowing without opening them. If you want good aftermarket batteries, KingSener has a solid reputation. Only go for aftermarket batteries that are upfront about being aftermarket and are open about the cells they use and well reviewed, or for sealed Lenovo batteries in original packaging. I recently bought a brand new, sealed 72Wh original battery. It sat sealed for so long the batteries went down below 3.1V per cell and the pack locked itself. Looking at the self discharge curves I'd expect this to be the case for any actually new battery. To make it work I had to open the battery and use a specialized charger to give it 0.1A of current until it got to 3.3V per cell, and I then programmed it to charge at 6A, after which the battery pack decided to start up.
  - ryantgtg 5y ago
    Thanks. I’ll try that brand. I buy mine from Encompass, the official seller of Lenovo batteries. So they shouldn’t be knockoffs, nor unsealed. But, one battery went from 90% health down to 30% in the course of six months. And they’re not cheap!

ohazi 5y ago

Generally pretty good. With tlp and a 5.10ish kernel, my T480 handles light web browsing at 3-5 W depending on display brightness (wqhd display). Heavier websites, high-res video decoding, etc. will bring it up to 7-10 W. Maybe 20 W when compiling something, or when attempting to use the (worthless) Nvidia GPU (which I leave powered down most of the time). It has a dual battery setup with a 24 Wh internal battery and a 72 Wh external battery (I use the bulbous 6-cell, but you can get a thinner one if you prefer), so even when setting the charge stop thresholds at 80% to preserve cell lifetime, the computer easily lasts all day on battery. That being said, it would be easy to find a random laptop that either idles at something stupid or that can't go to sleep properly because of just one wacky peripheral, making Linux power management seem bad. Half the battle is picking the right starting point (e.g. a Thinkpad), and then setting everything up so you can actually measure the power in all of the different states so that you can actually confirm that your setup works properly before relying on it and ending up disappointed at the airport.

robmsmt 5y ago
if you could point to how you configured your power management that would be great
- smoldesu 5y ago
  "sudo tlp start" :)
  - ohazi 5y ago
    Start with this. If there are peripherals you don't use (something as small as a Bluetooth adapter or as large as a GPU), figure out how to power them down, and get the computer to put them in that state by default. On ThinkPads (and probably on others), you can monitor the instantaneous power consumption by poking around in: /sys/class/power_supply/* There are widgets that can monitor this for you and alert you if anything seems amiss, but I just have a script that puts some text and symbols in my menu bar: https://github.com/ohazi/dotfiles/blob/master/bin/battery.sh https://github.com/ohazi/dotfiles/blob/master/bin/battery.sh You can use this to confirm that (for example) your wifi card is actually powering down when you ask it to.

sudosysgen 5y ago

Nowadays Windows consumes more power than Arch Linux with KDE given a processor underclock and power saving tweaks. On my X250 with a 72Wh external battery I can get 14h of battery life without sacrificing much of anything.