What is a realistic expectation for C720 battery life?

Eric2015
Eric2015 Member Posts: 1 New User
edited November 2023 in 2018 Archives

New out of the box, my first C720 never got more than 4-5 hours of battery life.  I did the full discharge then full recharge to try and recalibrate the battery, but no improvement.  So after contacting Acer they said this is a problem.  So I exchanged it at the same store I bought it.

 

Now my 2nd C720 I put on the charger for 12 hours before using it.  For about the first 15 minutes it showed estimates of 10-12 hours.  However this dropped quickly to 4-5 hours in about 30-40 minutes of use (just browsing the web).

 

I should mention I keep the screen brightness at a minium <50%.

 

Chrome OS Version:
V 36.0.1985.126
Platform 5841.74.0
Firmware Google_Peppy 4389.86.0

 

SW indicator says battery is at 88% and 5:21 time

battery_test shows:
Battery is Discharging (83% left)
Battery health: 98%
Please wait..
Battery discharged 1.2% in 300s.

I exchanged the first one at the store because of this problem.  Did they just get a bad batch?  Or are my expectations too high to really see 8.5 hour battery life with regular use?

 

Everyone else seems to say they get great battery life, but what does "great" really mean?  Can I watch a 8.5hr long movie?  Can I play a 3d graphic excelerated game for 8.5hrs?  Or can I just type text with screen at 20% for 8.5hrs?

 

Thanks,

Eric

 

__________________________________

Additional references to battery life and what I expect but don't seem to get:

http://www.trustedreviews.com/acer-c720-chromebook-review-battery-life-and-verdict-page-3

says: "intensive testing streaming Netflix continuously on default brightness it can get up to the 6-7 hour mark"

 

http://arstechnica.com/gadgets/2013/10/review-acer-and-haswell-give-chrome-os-the-battery-life-it-deserves/2/

says: "Our light Wi-Fi Web browsing test loops a set of webpages at the rate of one every 15 seconds until the computer dies. With the screen brightness set to 50 percent, the C720 lasted for 11 hours and 40 minutes, better even than Acer's optimistic estimate of 8.5 hours and much better than the six-ish hours managed by the Chromebook 11. The C720 does have a dimmer display than the Chromebook 11 though—with the brightness cranked to 100 percent, the C720 lasted for 8 hours 7 minutes, a still very impressive number."

Answers

  • IronFly
    IronFly ACE Posts: 18,413 Trailblazer

    i have nearly the same battery life as the reviews.

     

    i mainly use it to browse here and there and right now i have around 6 hours of battery life with 72% of charge.

    I'm not an Acer employee.
  • systemBuilder
    systemBuilder Member Posts: 3 New User
    edited February 2018
    I own a c720 i3 with 4GB of RAM.  This model would use the most power of any c720 model.  My laptop is pretty old (3.5 years), and is still using the original battery.  Log into your laptop, hit CTRL-ALT-T (capital T), and it opens the crosh shell.  Type "battery_test 0".  My chromebook, when fully charged and when at 60% brightness, has an estimated battery life of 4:30, with a battery_test of 88%.  Lately I have been running down the battery all the way to zero, which is a very bad thing for the battery.  A toyota Prius runs the battery from 60% to 40% and then recharges, to get an 8+ years battery life.

    To make your battery last as long as possible, ALWAYS use a charger whenever you can.  Try to use the battery only once every other day.  A typical Li-Ion battery loses a lot of capacity at 500 cycles, and is gone at 1000 cycles, so if you tend to run down your battery twice a day, you might get only 1.5 years out of your battery. 

    New batteries cost $32.95 on EBay and they are trivial to install.  Just remove all the screws on the back of the laptop (including the 12th screw which is UNDERNEATH the Acer try-to-scare-our-customers label), then use a guitar pick or soft butterknife to gently pry off the back (go all the way around there are at least 10 plastic latches.)  Then it's just 2 screws to release the battery & disconnect the connector, and then reinstall all 14 screws and you are back & running in about 5-8 minutes of work.  The c720 is a dream (i.e. really trivial) to work on, it's just 7 items sandwiched together (top-cover, LCD, bezel, keyboard assembly, motherboard, battery, back-panel).  

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