Here is a quick tip from François Beaufort to test the battery health of your Chromebook. All you have to do is enter the Chrome OS command line using Ctrl + Alt + T and enter the following command:
That will run a (very) short test and tell you how good your battery is now.
My Samsung Chromebook Series 5 550 shows 69% and I found at least one more 5 550 user with similar results on Google Plus. Pixel users seem to get around 90 – 95, and there are people reporting CR48 still holding up at 100%. Test your battery health now and let me know in comments!
A quick note on Batter Health from Wikipedia:
State of health (SOH) is a figure of merit of the condition of a battery (or a cell, or a battery pack), compared to its ideal conditions. The units of SOH are percent points (100% = the battery’s conditions match the battery’s specifications).
Typically, a battery’s SOH will be 100% at the time of manufacture and will decrease over time and use. However, a battery’s performance at the time of manufacture may not meet its specifications, in which case its initial SOH will be less than 100%.
So, what’s your number?