# Low battery capacity

## FrostyX

Hi I am confused about my battery. I used to have laptop for 4-5 hours on battery and now it is almost two. I checked acpi -i and wondered.

```
Battery 0: design capacity 4125 mAh, last full capacity 1967 mAh = 47%
```

 May I throw battery to the trash and buy a new one ?

But I am interested about another thing. One and half year I used ArchLinux and everything seems fine. Last six months I am using Gentoo and I have this problem. Can I ruin my battery because of wrong configuration (some bad power management settings) on my Gentoo?

Thanks

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## NeddySeagoon

FrostyX,

What you are seeing is the battery capacity reducing with charge/discharge cycles.

Its a feature of Lithium-Ion batteries.

Lithium is toxic and expodes on contact with water - recyle the battery properly for your own safety.

The battery charging is not controlled by your distro, charging is controlled by a special battery controller chip that measures charge in and out.

Battery life is affected by the condition of the battery, its state of charge when discharge begins and the load. Your operating hours on the battery will be reduced considerably with poor power management settings.  This does no harm to your battery though.

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## FrostyX

So if I understood correctly. With the worst power management settings on my Gentoo I can reduce operating time on battery, but I can't destroy it (for example speed up losing capacity). Right ?

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## mbar

How old is the battery/laptop? Can you estimate how many charge/discharge cycles you did?

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## cwr

Gentoo won't damage your battery - no linux distribution will - but some distros may be

better at power-saving than others.  I don't think Gentoo is especially poor in this

respect, and most of the battery handling is anyway built into the hardware, so the

most likely cause of your problems is an ageing battery.

My current battery has lost about 8 percent of its full capacity over two years, and I have

some ten year old batteries down to 30 percent of initial full capacity.

The best approach would be to find a way of checking discharge rates, and see how much

power the different OSes use.  In a recent Gentoo look under /sys/class/power_supply/BAT0

and there should be some helpful information.

Will

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## FrostyX

I have original battery in two years old ThinkPad SL510.

There is some informations from /sys/class/power_supply/BAT1

```

cd /sys/class/power_supply/BAT1

$[FrostyX  BAT1]-> cat cycle_count 

0

$[FrostyX  BAT1]-> cat energy_full

23860000

$[FrostyX  BAT1]-> cat energy_full_design 

51840000

$[FrostyX  BAT1]-> cat energy_now 

7430000

$[FrostyX  BAT1]-> cat voltage_min_design 

10800000

$[FrostyX  BAT1]-> cat voltage_now 

12481000

$[FrostyX  BAT1]-> cat model_name 

42T4708

$[FrostyX  BAT1]-> cat technology 

Li-ion

$[FrostyX  BAT1]-> cat power_now 

26401000

```

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## cwr

Yes, well, it looks as if your battery is down to around 45% of it's original capacity, which

in two years use surprises me.  It might be worth asking around, or digging through

Google, to see if this machine often has battery problems. As I said, my current (elderly)

Thinkpad has lost about 8% in two years from a replacement battery.

Anyhow, that's why your laptop endurance is about halved.

Sorry - Will

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## dmpogo

BTW,   from time to time manufacturers have recalls on batteries,  check with your laptop maker, you may be lucky.  Usually batteries last longer than two years, but death in two is not unheard of.    Also,  laptops often comes with windows tool to "restore"  battery capacity (they do it but several charge-discharge cycles),   which sometimes helps to get back a bit of full-charge capacity.

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