Battery drain tests (3G vs 4G vs screen vs idle)

[sperho]

I was curious about battery drain on my phone under a few different conditions so I ran a few tests and thought I would share the results. I got curious about battery drain after doing some testing showed that Light Flow, with my configuration of multiple notifications allowing the LED to cycle colors, was causing excessive battery drain by keeping the phone out of Deep Sleep. I get a lot of notifications during the work day and battery was going a lot faster than I though it should have been. I've since stopped using Light Flow and am pleased with idle times and battery life compared to when I had LF enabled.

Percentages and times were calibrated from a screenshot using Photoshop CS4 Extended using the measurement tools (basic pixel = length stuff) and the screenshots are below. I did the 4G Netflix test twice to see how repeatable this kind of measurement was and the drain rate was within 0.1% of the first time I ran the test. Not bad.

Test conditions:

1. I left bluetooth on for these, wi-fi off, and screen on auto brightness.
2. All tests were performed in a dim room and the screen brightness was low because of this.
3. Samsung extended battery was installed.
4. Rooted and unlocked, otherwise bone-stock ICS 4.0.2. Signal for 3G was 2-3 bars. Signal for 4G was 2-3 bars.
5. Data sync was enabled, which includes a POP email account with a 10 min fetch interval, TouchDown for Exchange email with push-enabled, GTalk on, GMail sync on.
6. All tests performed over the course of 2 days (yesterday and today) and tests were performed only after the battery had been off the charger for 10-15 minutes, so its voltage had time to stabilize a little bit.

This test was meant to be representative of how I have my phone set up pretty much all of the time, so your results might vary, but some might find the relative drain rates of interest nonetheless.

I measured the following:

1. drain under only occasional screen-ons with 3G enabled.
2. drain with no screen-ons with 3G enabled.
3. drain with no screen-ons with 4G enabled.
4. drain while downloading a 456MB file from Dropbox with 3G data, screen off.
5. same as 4, but with 4G data.
6. drain while watching 45 minutes of Burn Notice on Netflix over 3G.
7. same as 6, but over 4G.
8. screen on only

My conclusions under my test conditions are:

1. Drain while idling with 4G on is almost 2X that of 3G, but it is not terrible, coming in at only 1.7%/hour.
2. Idle drain in general is surprisingly good despite having push enabled on several services.
3. When transferring a lot of data, 4G is MUCH more efficient than 3G, not because it uses less power per unit time, per se, but because the radio is working hard for a LOT less time on a decent connection.
4. Netflix (or quite possibly, simply video playback) chews the bejeebers out of the battery, regardless of 3G or 4G connection.
5. Screen on drain when the brightness is low isn't all that bad.
6. I am guessing that like the desktop version of Netflix, the Android Netflix app sends more data when you have higher bandwidth connection, thus at least partially accounting for the 38.2%/hour drain rate on 4G compared to the 33.1%/hour drain rate on 3G.

That's about it and YMMV - so remember that before you post...

 

[jbdan]

Great comparo much appreciated!

 

[Sandroidfan]

Appreciate posting this. very thorough and nice testing. I really think battery life is one of the pros of Nexus, not cons. It lasts long enough once it's set up properly. This is not so well known to other phone users and often they perceive Nexus is poor on battery.

 

[dhworph]

I used to pay pretty close attention to my overnight sleep drain. I have done lots of charges to "100% Full" and then do a fresh reboot, unplug and go to sleep. On a 1-2 bar 4G connection, with GPS, Google Sync and backup on, and no background apps other than AVG and the stock 4.0.2 OS, I end up with 88% in the morning - a 12% drain over an 8 hour period - 1.5%/hour. I've seen as low as 1.3% per hour drain on 4G.

On Airplane mode, my drain was from only a total of 1-2% for the whole night.

I can't remember if I tested 3G or not. I didn't notice any difference by just turning off GPS or Sync. However, just turning data off and leaving voice on saves quite a bit of battery too.

 

[sperho]

Full disclosure. I mistakenly measured the 4G data d/l at the wrong location in the picture that I had originally uploaded. I fixed it and replaced the image above with the correct measurement. The drain rate is about 4X of what the picture showed originally, but the conclusion remains the same: large downloads on 4G use MUCH less battery per GB than a 3G download. Slightly higher percentage drain/hour than 3G, not surprisingly.

 

[ExDementia]

Thanks for posting that up! It confirmed my suspicions that LTE battery life wasn't as bad as everyone (myself included) might think.

For the past two weeks I have left 4g on 95% of the time, and only turning it off under special circumstances (like being in a spotty 4g coverage area). My battery lasts me all day every time with pretty moderate usage and throwing it on the car charger when ever I drive anywhere.

 

[sperho]

Made another measurement today. 4G enabled, continuous voice call with 2-3 bars, bluetooth over the first half of the call, then I switched over to the handset only. 16.1%/h. Surprisingly, no significant difference in visually perceivable drain rate between the BT headset portion of the call and the handset only portion of the call.

 

[hlsilver]

Well at least I can be pretty sure there's something wrong with my phone now. Left 3g on while at work the other day and always have good signal. After 3 hours I went from 93% to ~70%. There's no way I should be losing 7-8% per hour while idling 3g on. Originally thought it was because of the Facebook app which destroys battery but I've only opened it once since I downloaded it which was the day before. Guess I'm going back to stock and starting over root/rom...