How to check if my battery is healthy?

Question

My Lenovo ThinkPad T61 is rather old, and a couple of years ago I had to replace the battery as the old one was dead. Now the replacement battery seems like dying a slow death, but I get conflicting data from xfce4-power-manager. So I'm wondering if there is a way to check whether the battery is healthy.

The symptoms are as follows:

• The power manager indicates that the battery is fully charged
• If I disconnect the AC charger, then the battery status jumps to 47% or similar in less than 5min
• And in less than 15min the laptop runs out of juice and shuts down

I tried to check upower data:

root@malou-laptop:/home/liv# upower --enumerate
/org/freedesktop/UPower/devices/line_power_AC
/org/freedesktop/UPower/devices/battery_BAT0
root@malou-laptop:/home/liv# upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:00/PNP0C09:00/PNP0C0A:00/power_supply/BAT0
  vendor:               SANYO
  model:                92P1137
  serial:               885
  power supply:         yes
  updated:              Wed 19 Feb 2014 09:35:37 PM CET (23 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               fully-charged
    energy:              70.38 Wh
    energy-empty:        0 Wh
    energy-full:         72.42 Wh
    energy-full-design:  71.28 Wh
    energy-rate:         26.561 W
    voltage:             12.4 V
    percentage:          97.1831%
    capacity:            100%
    technology:          lithium-ion

I also looked at ACPI data:

root@malou-laptop:/home/liv# cat /proc/acpi/battery/BAT0/info 
present:                 yes
design capacity:         71280 mWh
last full capacity:      72420 mWh
battery technology:      rechargeable
design voltage:          10800 mV
design capacity warning: 3621 mWh
design capacity low:     200 mWh
cycle count:          0
capacity granularity 1:  1 mWh
capacity granularity 2:  1 mWh
model number:            92P1137
serial number:             885
battery type:            LION
OEM info:                SANYO
root@malou-laptop:/home/liv# cat /proc/acpi/battery/BAT0/state 
present:                 yes
capacity state:          ok
charging state:          charged
present rate:            0 mW
remaining capacity:      70380 mWh
present voltage:         12400 mV

But I cannot pinpoint anything suspicious: the design capacity and last full capacity seem healthy to me.

So is there some other utility that could indicate whether the battery is working as expected, or needs replaced?

Solution 1

I don't know why you're looking for corroborating evidence from the system, when you have solid empirical evidence. The battery won't hold a charge. Period, end of story.

I'd be happier if I saw a high charge cycle count. Lithium ion isn't good for more than about 500 charge cycles.

Another datum, which won't appear in the places you've been looking, is how much of the laptop's usage life on this new battery has been while plugged in, and whether it's frequently gone through a full discharge/charge cycle.

Too many people use laptops as if they were small desktops, leaving them plugged in most of the time. This is not healthy for the battery. The analogy I like to use is that a toy balloon will last longer if you blow it up only part way, rather than blow it up as far as it can go and leave it there. A full charge on the battery increases some of the stresses on it.

Solution 2

You can also check the battery health by using the inxi tool with this command :

$ ./inxi -Bxxx
Battery:   ID-1: BAT0 charge: 39.5 Wh condition: 40.3/47.5 Wh (85%) volts: 10.8/10.8 model: PA5109U-1BRS type: Li-ion 
           serial: FA80 status: Discharging

and check the condition value.

Solution 3

full explain options and example

on Ubuntu, you can open the Power Statistics application from the Dash. Look at the “Laptop battery” section. “Energy when full” is how much power your battery can currently store when it’s fully charged. “Energy (design)” is how much power your battery could originally store when it’s fully charged.

Divide “Energy when full” by “Energy (design)”, multiple the result by 100, and you’ll get a percentage. For example, in the screenshot below, we’d do the following math:

(44.8 / 54.3) * 100 = 82.5%

This means the battery currently holds 82.5% of its original capacity. That’s not too bad. You won’t be at 100% unless you just purchased a new laptop. But if it’s low—under 50%, for example—and you aren’t getting much time out of your battery, you may just need to replace the battery.

If you don’t have the Power Statistics application on your Linux distribution, you can get this information via a few terminal commands.

Open a Terminal window and run the following commands:

cat /sys/class/power_supply/BAT0/charge_full

cat /sys/class/power_supply/BAT0/charge_full_design

Divide the first number by the second number and multiple by 100 to get the percentage of the battery’s original capacity. For example, for the screenshot below, we’d do the following math:

(5901000 / 7150000) * 100 = 82.5%

This means the battery is currently at 82.5% of its original factory capacity.

By Chris Hoffman.

easiest simple explanation and example

Comments

[landroni]

What does cycle count: 0 indicate? That the sensors do not report this info?

[derobert]

@landroni Yes, most likely 0 just means it isn't tracked, or at least isn't reported by ACPI to Linux.

[GPraz]

Should we charge the battery only up to 50-60% then let it discharge for better lifespan?