Linux @lemmy.ml Floopquist @lemmy.org 2mo ago

Linux: How to use energy better in general by fine-tuning laptop battery?

Hello,

I just found out about TLP - a module to download with apt, which is a good utility for maintaining the laptop battery. You can set a minimum charge value, and a maximum charge value. But it is not sufficient for my use case. My question is - is there any utility I can use to discharge the battery WHILE connected to AC?

The reason behind this is: I want to use the solar power during the day to charge up the battery to 80 or 90% and then discharge the battery in the evening to 15-20%. Afterwards use AC power again. The solar energy during mid-day is cheaper and available in abundance.

On a big level with many computers this could make a good impact on the energy network, or am I wrong?

14 comments

Some laptop battery firmware allows you to force discharge even when connected to AC, and if your laptop can use the tlp recalibrate or tlp discharge commands then yours is supported.

I use this to power my thinkpad servers off of their own batteries during a power outage, to reduce load on my UPS. Great feature.
- Interesting setup. How would you tell your Thinkpads if there's a power outage?
  
  The ups has data output to my firewall/router via usb, which the baremetal servers all connect to via apcupsd. When the ups loses or regains AC power, it broadcasts a message to all of them and they're each scripted to act accordingly: laptops run on their own batteries, vms migrate over to laptops, non-vital hardware shuts down, etc.
I don't know but is that power actually worth more than battery cycles due to discharging and recharging?
Sounds like a smart socket might do what you need, externally, with some coding.
- Thank you, I like the idea. Will research in this way.
I've got a 2021 Dell laptop. In uefi, you can set charge times and type of charge, 50%,80%, full, and smart. I think it's in like 1/2 hour blocks by day. By that I mean on (day of week) from 9:30am to 6:00pm charge full, different day may have different settings. .
modern laptops are like 8w right? it's probably a few orders of magnitude lower than the power consumption of your appliances
- The converter says "Output: 65W" So it would be something, and a good place to start as the battery is there anyway and is plugged in all the time too, anyway.
  
  That's the absolute maximum output, a typical laptop uses more like 2-6W while running.
  
  Plus cycling the battery like that will wear it out faster, and they're generally only rated for 500 or so cycles. The replacement cost would likely easily over come any savings.
Well, you will have excess solar power during the day, so just keep it plugged in to the solar while solar is available. Then, just unplug the laptop in the evening until you get to 15-20%.

Trying to force the laptop to discharge while plugged in is colossally more trouble than it's worth.
- Unplugging by hand is a bad solution. I want to have this even when I am not at home, it has to be automated.

14 comments