Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Lithium-based Batteries are not supposed to constantly sit a maximum charge. This damages them and reduces their lifespan. This is why some people take the battery out when using the laptop plugged in; but I don't want to do this, because then a power outage could cause data loss.

On the Samsung N150 netbook, there is a BIOS SETUP option to set the max battery charge level to 80%. Then you can leave the netbook plugged in, with the battery installed, and still preserve the battery's lifespan. I want to do it with my HP G42-230BR laptop, which does not have such a BIOS SETUP option. It should still be possible with software, right?

I have Googled and did not found how to do it:|linux+partial+charge|recharge+battery+life

Do you know how to do it?

Thank you very much for your attention

share|improve this question
Looks like a duplicate of… – Ed Manet Sep 25 '12 at 18:59
@EdManet Thank you very much for pointing it out, and sorry for the duplicate. But that other question is also without answer, so I am still waiting for an answer. – Jorge Sep 25 '12 at 19:43
Check out the first answer to this question. It pretty much dispels the myth of battery life:… – Ed Manet Sep 25 '12 at 19:45
That "myth" did not come from a chain email; it came from… and was confirmed by Ars Technica and Life Hacker:… also, I cannot imagine that Samsung engineers would have the trouble to ship "Samsung battery life extender" (which does what I want) if it didn't help. – Jorge Sep 25 '12 at 20:13

There is 80% charge and there is 80% charge.

Electronic equipment (cell phones, laptops, etc) require a certain minimum voltage to be able to function. Simpler devices, like flash lights, can function down to near zero charge (albeit whether usable is another question)

When manufacturers state that a battery should not fall below 80%, they talk about the kind of depletion that you get when you use a battery till it is completely flat, eg due to a continuous drain, such as by flash light globe.

A cellphone, or laptop however would cut out long before this... probably even before a battery reaches this 80% limit. This is due to the internal resistance of the battery going up, which causes a voltage drop under load. If the battery is near enough to fully charged, e.g above a certain threshold, this voltage drop doesn't show up when using a simple meter to test battery charge, as these meters does not put enough load on the battery to cause the internal resistance to have a real effect.

Cell phones and such have "intelligent" managed batteries to be able to report to you how long you can still use the battery, e.g before it reach the threshold where the internal resistance causes the supplied voltage to go too low to be able to power the device.

So there are two measures of battery charge:

  1. That reported by the battery indicator on the cellphone is "time until battery reaches cut-off threshold"
  2. The actual amount of charge resident in the battery, regardless of whether it can be used by a specific device.

This complicates the whole situation: How do you control the device to not use the battery below a certain threshold (Type 2 above), when that threshold is measured on a different scale compared to that reported by the battery level management circuitry (Type 1 above)

I'm quite sure there is no way to do this, but in all likeliness your device will never deplete the battery to below the 80% manufacturer safety margin, so this is not a real issue.

share|improve this answer
This is the exact opposite to what the OP is asking. Read the question again. – Benubird Oct 29 '14 at 7:43

Slightly duplicate of How can I limit battery charging to 80% capacity?, but I won't mind. And for those that say the 80% thing is a myth, that's not what Jorge ask for; he wanted to know how to enable it, whether or not it's a myth...discuss that elsewhere.

If you don't have an option in your BIOS, it's difficult to impossible to override the hardware in your computer without the proprietary company that made your computer (HP) making a special script for you. Look for something like that, otherwise, it won't work.

Maybe look in your BIOS again. Maybe also (if you are daring enough), to update your BIOS. This is tricky, but I will not explain it here. That MIGHT allow you enable this setting. I still think that it would be in your BIOS if anywhere, check over it again. If you do update your BIOS, ensure it's a newer version, AND that it includes the "enable batter saver" option that you want (you may have to read the update notes (bleah!)).

Hope this helps! If it does, +1 me :).


share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.