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OsakaTom
Jul 22, 2011, 11:27 PM
Just picked up an an 'ultimate' 13" i7 2011 MB Air, and proceeded to run a stress test/battery run-down.

Stress/Battery Test:

Settings: I set brightness at ~65%, keyboard backlight at 50%, WiFi on, Bluetooth on, speakers off. Aside from Chrome, nothing extra was installed beyond what comes with Lion. In one Chrome window I ran a looping 720p Youtube video. In a second, I ran Pandora, playing through a radio station. iTunes was open on a second desktop, as was mail, albeit minimized. Finally, a single Safari window was open and running a timer. Perhaps not surprisingly, the fans kicked in at full gear through almost the entire test.

Results: Under these conditions, from a full, fresh charge, the system managed 2 hours 24 minutes.

So, MacRumors community, does this seem about par for what we should expect for relatively heavy (Flash) use, or does this seem a bit low? I know running Flash won't get anywhere close to the 7 hour mark Apple reports, but less than 2:30 seems a bit low...

I'll update the thread with a more standard test to see if my Air's battery is on the short side. It should also be noted that before I started the test, the battery life indicator was only reporting 4 hours life, which is a bit odd.



miles01110
Jul 22, 2011, 11:28 PM
Seems reasonable to me.

calvol
Jul 22, 2011, 11:39 PM
That seems low. It would be good to know what the CPU temp was during the test.

kenwalton
Jul 22, 2011, 11:45 PM
This doesn't sound out of line to me. I just upgraded to this same model myself from a 2010 13' Ultimate MBA.

Keep in mind these things:
* Flash shreds batteries on these machines. Even a little bit here and there cuts down battery life significantly.
* 720p video sucks a lot of battery.
* Chrome uses up more battery than Safari.

If you were using enough juice to keep the fans running the whole time, you were using it at a rate that would deplete the battery in less than 3 hours.

Try this:
* Turn off bluetooth
* Turn the brightness down to 40%
* Close chrome and keep a few tabs open in Safari with a flash blocker enabled.

Under these circumstances you should easily be able to surf the web casually for 6-7 hours or more. I was once able to get 9.5 hours like this on my old MBA, and this one feels similar. My battery is showing 6:44 right now with 88% remaining.

PaulWog
Jul 22, 2011, 11:49 PM
11-inch would likely get closer to 1:45 doing that.

Sounds about right I guess.

Though battery life is somewhat of a disappointment. I think. It's alright but Apple really does advertise the absolute maximum on their "up to". It would be better of they were a tad bit more realistic. I could only get the "up to" rated amount if I turned off wifi, turned off bluetooth, turned screen to lowest brightness, turned backlit off, turned off sound, and only did word processing.

On my 11-inch I'm getting something like 3 hours with Wi-Fi on browsing the web. I have flash blocker too. That's with about 50% brightness and backlit off.

ender21
Jul 23, 2011, 12:04 AM
I wonder what the difference would be if you re-ran the test exactly as you did the first time, but this time run the same 720p Loop with Flash Disabled and using YouTube's HTML5 feed instead.

unagimiyagi
Jul 23, 2011, 12:05 AM
Not being faceitious:

Take the manufacturer's claimed battery life and multiply it by 0.6 or 0.7

That's the real world life that you're going to get. That's been my formula and it helps to set expectations. Doing what the OP said, I fully would expect to get his apallingly low battery life. I find that under load, apple's laptops have identical battery life to any run of the mill windows pc. Apple is really good at saving juice when the computer is idle only. When you're under load, you are governed by Intel's power draw designs. So I have concluded that if you are a heavy multitasker and do cpu-intensive things, there's really no point in looking at battery life when laptop shopping because laptops won't differentiate themselves as much under those situations. They will all disappoint you. The only way you can get long run times doing stuff under heavy load is by throwing more battery watt-hours at it (increase the supply end of things). So you have to get an extended battery. Or just plug in. Plus when you throw in the fact that battery run times degrade drastically over time anyway, perhaps battery life is overrated. I will still conclude that Apple has the best runtimes currently available per watt-hour. So it's not like Apple's runtimes are wrong, it's just that there is no tech right now to address using a laptop under load and give you the 6-7 hours.

christophermdia
Jul 23, 2011, 12:33 AM
few hours for me online and I have 6:10 left....

OsakaTom
Jul 23, 2011, 12:37 AM
Funny, in one sense, I'm somewhat happy that my results don't seem terribly out of line (didn't get a lemon!). On the other hand, that is somewhat unfortunate that high load really, really destroys battery life. I imagine the i7 is likely knocking down the lifespan a bit too, as most of the reviews seemed to test the i5 version. That said, the system was still incredibly responsive when I checked it a few times during the test.


A couple other notes on the test: I used Chrome instead of Safari to avoid actually installing Flash (Chrome has it baked in). I wanted the YouTube feed to automatically loop, so I used the Flash player and youtuberepeater. I used the Pandora Flash player, not the HTML5 version, but I do have access to the HTML5 version.


I plan on running a few more variants, and I'll post the results, including a 720p H264 rundown, a Spotify streaming + light use rundown, and a second, no-Flash stress test (and spot check temps). So long as this can safely achieve 5-6 hours with either Pandora HTML5 or Spotify + light web browsing/word processing, I'll be happy!

Out of curiosity, on a full charge, what sort of times are you all seeing on your Airs?

miles01110
Jul 23, 2011, 12:41 AM
On the other hand, that is somewhat unfortunate that high load really, really destroys battery life.

Did you expect differently? I just assumed it was fairly obvious that higher load = more power = shorter time on the battery.

Aksta
Jul 23, 2011, 12:43 AM
try reallyrefreshing.com for your light browsing battery test. the old macbook air 13" maxed out got 7 hours and 21 with 53% brightness using chrome.

eeptman
Jul 23, 2011, 09:01 AM
try reallyrefreshing.com for your light browsing battery test. the old macbook air 13" maxed out got 7 hours and 21 with 53% brightness using chrome.
Thanks for the web link. I just test my 13" i7 shortly. Here comes the result:

• Google Chrome v13.0.782.99 beta + Flash & Ad block + 50% Brightness + {Mail, Little Snitch, iStat, Moom, Cookies, Caffeine} in background + App Tamer
10% battery life = 48 mins
20% battery life = 1hr 36m

jackyyeow
Jul 23, 2011, 09:11 AM
Thanks for the web link. I just test my 13" i7 shortly. Here comes the result:

Google Chrome v13.0.782.99 beta + Flash & Ad block + 50% Brightness + Mail in background
10% battery life = 48 mins
20% battery life = 1hr 36m

Screen auto dim/sleep?

eeptman
Jul 23, 2011, 09:13 AM
Screen auto dim/sleep?Nope, I use Caffeine to keep screen alive.
And the CPU temp is around 4x~50C

For all MBA users, try a software, App Tamer v1.1d1 to see if you can save more battery life.

http://www.stclairsoft.com/download/AppTamer-1.1d1.zip

OsakaTom
Jul 23, 2011, 10:23 PM
Quick update on a more 'light-use' test:

Running the reallyrefreshing.com test in Safari w/ no Flash (great link!) on Desktop 1, plus Spotify playing, Mail, and a second Safari window on Desktop 2, Bluetooth off. Brightness at 50% (give or take a notch), Speakers at 1 bar, Keyboard Backlight at 2 bars.

(Add in Word or Pages, and this is my use scenario 75% of the time)

10% drained = 36 min
100% drained = 6 hours 15min

Pogopuschel
Jul 23, 2011, 10:29 PM
Quick update on a more 'light-use' test:

Running the reallyrefreshing.com test in Safari w/ no Flash (great link!) on Desktop 1, plus Spotify playing, Mail, and a second Safari window on Desktop 2, Bluetooth off. Brightness at 50% (give or take a notch), Speakers at 1 bar, Keyboard Backlight at 2 bars.

(Add in Word or Pages, and this is my use scenario 75% of the time)

10% drained = 36 min
100% drained = 6 hours 15min
Doesn't sound too bad to me. Would you mind rerunning the test (only draining 10% is okay) without Spotify in the background?

fitshaced
Jul 23, 2011, 10:43 PM
I keep my MBA 13 on full brightness and can surf the web for about 4.5 hours before it gets down to below 10%.

I think I'd only use it for web surfing when on battery if I wanted a long use of it.

Powered for long use for anything else.

But I always want full brightness.

Very happy with the battery.

onthecouchagain
Jul 23, 2011, 10:55 PM
Am I the only one that can't use the Air without at least 70% brightness setting? I'm really comfortable at 80%.

ender21
Jul 23, 2011, 11:00 PM
Am I the only one that can't use the Air without at least 70% brightness setting? I'm really comfortable at 80%.

Wow that's bright. I'm usually at 50% or below. But I do keep auto-brightness on.


@fitshaced - Great name, and like your rig. I have the same lenses as you but went with the 60D.

treynolds
Jul 23, 2011, 11:17 PM
Wow that's bright. I'm usually at 50% or below. But I do keep auto-brightness on.

Second that, I can't stand super bright screen; too much eye strain. I keep it at 50% or below unless I'm outside.

myrison
Jul 24, 2011, 07:50 PM
Quick update on a more 'light-use' test:

Running the reallyrefreshing.com test in Safari w/ no Flash (great link!) on Desktop 1, plus Spotify playing, Mail, and a second Safari window on Desktop 2, Bluetooth off. Brightness at 50% (give or take a notch), Speakers at 1 bar, Keyboard Backlight at 2 bars.

(Add in Word or Pages, and this is my use scenario 75% of the time)

10% drained = 36 min
100% drained = 6 hours 15min

This seems awfully good to me. I have the new i5 13" and ran essentially the same test. 50% key and screen brightness, Spotify running with speakers @3 bars, *Flash enabled, and it died in < 4.5 hours. I'll run a few more tests with and without Flash and post back.

I'd be interested to see others' results as well.

OsakaTom
Jul 24, 2011, 07:54 PM
So, running that same 'light-use' test, this time without Spotify running (so one Safari window refreshing, mail open, brightness at 50% and keyboard backlight on at near minimum), and without a second desktop gives the following results:

10% drain = 48 min

Which is exactly what someone else posted above for similar settings (except I used Safari instead of Chrome).

That would give about 8 hours of run-time!! Which means that first showing on Flash looks to be accurate. Talk about a battery killer. Spotify also does sap up a fair bit of battery use, which is certainly to be expected. All in all, it looks like the Air does indeed live up to it's battery life claims under light use scenarios!