Difference between revisions of "Template:Battery Testing"

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===Understanding Laptop Batteries===
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__NOTOC__
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The rechargeable batteries that power today's laptops are much more complex than the batteries typically found in other consumer electronic devices. They use sophisticated chemistry and control circuitry to maximize their runtime and longevity across years of use and potentially hundreds of charge/discharge cycles. Understanding their behavior - especially ones that have seen significant use - can be difficult but is very important for our Laptop Build processes. This guide is intended to help you measure and interpret a battery's vital signs and determine how much useful capacity remains.
 
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'''Checking the State of a Battery''' <br>
 
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&#9744; To check and monitor the state of the battery, open a terminal and type: <br>
 
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<code>
 
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watch -n3 -d cat /proc/acpi/battery/*/*
 
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</code>
 
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* The window should now display many lines of information about the battery that refresh every 3 seconds or so. The most important lines to look for are shown below with values taken from a healthy battery as an example. Other lines have been intentionally left out of this example and replaced with a '''-''', but will appear in real-world use. Real-world values may be significantly different, use different units, or missing entirely.
 
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'''Example'''<br><code>
 
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design capacity:      5200 mAh
 
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last full capacity:    4331 mAh   
 
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-
 
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design voltage:        11100 mV
 
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-
 
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charging state:        charging
 
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present rate:          1549 mA
 
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remaining capacity:    3679 mAh
 
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present voltage:      12358 mV
 
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</code>
 
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'''Battery Capacity'''<br>
 
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In this example we can see from the difference between the <code>last full capacity</code> and <code>design capacity</code> that the battery has seen some use but still has about 83% of its original capacity. If the <code>last full capacity</code> is less than 30% of the <code>design capacity</code>, the battery may end up being too worn out to function correctly. <br>
 
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'''Charging'''<br>
 
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We can also see from the <code>charging state</code> and <code>present rate</code> that it is charging at a healthy rate, and we would expect the value for <code>remaining capacity</code> to increase steadily until it is at or near the value for <code>last full capacity</code>. A battery will typically charge slower and slower as it approaches its <code>last full capacity</code>; when it is fully charged the <code>charging state</code> should change to <code>charged</code> and the <code>present rate</code> should be at or very near <code>0 mA</code>. <br>
 
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'''Battery Voltage'''<br>
 
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You may also have noticed that the <code>present voltage</code> is actually somewhat higher than the <code>design voltage</code>; this is normal for a healthy battery, and when the battery is discharging the value will drop initially then settle in around or a bit below its <code>design voltage</code>. If a battery has
 
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===Battery Charging and Testing===
 
===Battery Charging and Testing===
 
'''Confirm the Battery is Fully Charged''' <br>
 
'''Confirm the Battery is Fully Charged''' <br>
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  watch -n3 -d cat /proc/acpi/battery/*/*
 
  watch -n3 -d cat /proc/acpi/battery/*/*
 
</code>
 
</code>
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*If the battery seems like it is healthy and charging normally, check the '''Start''' box next to Battery Charge on the Keeper Label and let it finish charging. <br>
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*If the battery seems like it is healthy and charging normally, check the '''Start''' box next to Battery Charge on the Keeper Label and let it finish charging. <br><br>
  
 
'''Test Battery Life'''<br>
 
'''Test Battery Life'''<br>
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&#9744; When the battery is fully charged, open a terminal and run the following command: <br>
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&#9744; When the battery is fully charged, open a terminal and run: <br>
 
  <code>batterytest</code><br>
 
  <code>batterytest</code><br>
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*Open a second Terminal ('''hint:''' press '''Super''' + '''T''' to quickly open a new terminal window) and run:
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&#9744; Open a second Terminal ('''hint:''' press '''Super''' + '''T''' to quickly open a new terminal window) and run:
 
  <code>
 
  <code>
 
  while : ; do stress-test ; sleep 300 ; done
 
  while : ; do stress-test ; sleep 300 ; done
 
  </code>
 
  </code>
 
&#9744; Disconnect the AC adapter from the power outlet, but keep it with the laptop for later. <br>
 
&#9744; Disconnect the AC adapter from the power outlet, but keep it with the laptop for later. <br>
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&#9744; Get a '''Battery Testing''' label from the wall next to the testing shelf and stick it to the palm rest of the laptop.
 
<blockquote>
 
<blockquote>
 
'''How it works'''<br>
 
'''How it works'''<br>
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The laptop will run the stress-test in a loop until it runs out of power. For every minute the laptop is on during battery testing, a line of text is logged in a file called <code>bat_mon</code>. When battery test is run again, the script counts up the number of lines of text in the <code>bat_mon</code> file, and outputs the number as the number of minutes the battery lasted.
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The laptop will run 3 minutes of <code>stress-test</code>, then 5 minutes at idle, in a loop until it runs out of power and shuts off. For every minute the laptop is on during battery testing, a line of text is logged in a file called <code>bat_mon</code>. When battery test is run again, the script checks for the <code>bat_mon</code> file and counts up the number of lines of text in the file, then outputs the number as the number of minutes the battery lasted.
 
</blockquote>
 
</blockquote>
 
[[Category:Laptops]]
 
[[Category:Laptops]]

Latest revision as of 13:51, 12 October 2013

Battery Charging and Testing

Confirm the Battery is Fully Charged
☐ Set the laptop on the testing shelf and make sure it is plugged in to a power outlet.
☐ To monitor the state of the battery, open a terminal and type: 

watch -n3 -d cat /proc/acpi/battery/*/*

  • If the battery seems like it is healthy and charging normally, check the Start box next to Battery Charge on the Keeper Label and let it finish charging.

Test Battery Life
☐ When the battery is fully charged, open a terminal and run: 

batterytest

☐ Open a second Terminal (hint: press Super + T to quickly open a new terminal window) and run: 


while : ; do stress-test ; sleep 300 ; done

☐ Disconnect the AC adapter from the power outlet, but keep it with the laptop for later.
☐ Get a Battery Testing label from the wall next to the testing shelf and stick it to the palm rest of the laptop.

How it works
The laptop will run 3 minutes of stress-test, then 5 minutes at idle, in a loop until it runs out of power and shuts off. For every minute the laptop is on during battery testing, a line of text is logged in a file called bat_mon. When battery test is run again, the script checks for the bat_mon file and counts up the number of lines of text in the file, then outputs the number as the number of minutes the battery lasted.

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