John Galea's Blog

My blog on Gadgets and the like

Samsung S2 LTE power consumption

One of the things missing from my S2 LTE review was power consumption. I needed to wait for a spare battery to arrive to allow me to do the numbers. Well I’ve had time to run the numbers now. I drive a car with a V8. And while it isn’t about to get the fuel economy of a econobox how bad it is depends on how much of the power you use. The V8 is there and if you push it then you eat up the fuel. This phone has two V8s, ok enough of the analogy 🙂 Had to have some fun!

There are two components in this phone that can consume a TON of power. The dual core 1.5GHZ processors are (for now) the fastest things out there. Android ICS does a fabulous job of keeping the second CPU off as much as possible and reducing the clock speed of both CPUs. Almost too good. I think some of the sluggishness of this phone is directly related to this.

The second is the LTE radio. In the past everytime the data rate has gone up on the mobile phones, so has the power consumption. The size of the batteries has not increased proportionally and we as users deal with worse and worse battery life. Personally I would not consider a phone I can’t carry along a spare battery with me for emergencies. A lot of phones today barely make it through a work day without even discussing an evening on top of it.

So for this next series of numbers I am going to concentrate on standby power. The device is just sitting there doing nothing with data on. I’m leaving it alone. I do these runs at night while I sleep to insure I don’t touch it, a call doesn’t come in etc. It also allows me to get enough data to make the data as accurate as possible. While the specific numbers can be very specific to the phone and what’s running, the relative numbers should be similar for other devices. The last time I did an article like this was for me Samsung Captivate Glide.

The phone I am using for this is a Rogers Samsung S2 LTE I727 running Android 4.04.

Let’s review network speeds:
GSM also called Edge or 2G theoretical 220 Kb/s actual around 56-100K
4G/3G also called UTMS theoretical 21 Mb/s actual 3-7 Mb/s from what I have seen/heard
LTE theoretical 75 Mb/s actual 21-55 from what I have heard/seen

I often get people arguing with me about WIFI. So let’s set the record straight. WIFI on this phone and every other phone I’ve run this test on consumes less power than ANY cell data mode. Even edge. On WIFI this phone consumes 0.85% per hour or a projected battery life of 117.7 hours.

Now lets move over to the cell data modes. Let’s start at the bottom of the heap in terms of speed, edge. On this phone it consumes 0.87% per hour or a projected battery life of 114.6 hours. As you can see more than WIFI. Now I will admit that if you factor in the error of these two numbers at best it’s a wash. Now what that means is anytime you can switch over to WIFI do so and you can save precious battery power. I use Y5 to automatically turn WIFI on and off based on cell tower connections. This program is well done. It just works. Set it … and forget it 🙂

On 3G/4G (I can’t set the phone for one or the other so this is a blend unfortunately) it consumes 1.37% per hour or a projected battery life of 73.1 hours. So compared with edge 3g/4G consumes 56.80% more power and costs you a projected 41.5 hours of battery life. Wow.

On LTE it consumes 2.17% per hour or a projected battery life of 46.1 hours. So by comparison this is 149% more power (or a projected cost of over 69 hours of projected battery life) than edge and 59% (or a projected cost of over 27 hours of projected battery life) more power than 3G/4G.

Now one of the more unfortunate things is Android does not allow you to automatically change your network mode so this is a choice you will have to make on a given day. What’s more important network speed or battery life. Crappy decision to have to make. One of the reasons you can’t automatically change the network mode is because the cell radio has to be powered on and off to change the mode.

Now one of the things you can do automatically is turn data off. Let’s have a look at that:
On the 3G/4G network turning data off goes from 1.37% per hour down to 0.43% per hour saving a projected battery life of over 158.2 hours! On the LTE network turning data off power consumption goes from 2.17% per hour down to 0.63% per hour saving a projected battery life of over 112 hours!

Now this can be done easily by programs automatically. Battery defender for example will turn data off and quickly turn it back on when the screen is turned on. You can even program a range of time for it to be active such as while your at work. They use this for night time mode which just seems bizarre to me. Night time the device is more often than not plugged in.

Juice defender on the other hand
cycles data on and off reducing the demand on the battery. And again when the screen is turned on data is turned back on. The default for balanced mode is to turn data off every 15 minutes. So theoretically this should be capable of saving as much as 14/15s of data. I ran a test overnight and battery reduced from an average of 2.17% per hour down to 1.81% per hour. Looking at the logs sometimes it noted that it left data on because it noted something was using the data. The savings were a meagre 16.8%

Hopefully this article gives you some areas to focus on if you are trying to conserve power on a given day.


November 16, 2012 - Posted by | Android

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