Join Now

A software engineer living in Vancouver, Canada - http://www.antonypranata.com/

Always Remember that Mobile Device has Limited Battery Power

antonypr | 24 April, 2007 05:30

Recently I had a strange problem with my Nokia E61 device. The device needs to be charged every day. I was quite sure that the battery was still okay. The device was relatively new, about 1 month old. Before it happened, I could use my device for 3 - 4 days without charging.


I thought it must be from one of the applications that I have installed recently. I suspected one of the applications that I have just installed. Then, I decided to uninstall it (I am not going to disclose the name of the application). What happened after that? The problem with my battery was solved. I can use my device normally.


Why did it happen? Apparently, the application installed a server that runs in the background. I am not sure what the server is doing, but it empties the battery very fast.


As a mobile developer, how can we avoid this? Forum Nokia has a good paper, S60 Platform Effective Power and Resource Management. I won't repeat everything here; just highlight some of the important points:


  • Continuous timers, ticking too frequently (for example, more than once every five seconds), can adversely affect power consumption.
  • If an application is moved to the background, it should, where appropriate, be paused and timers should be stopped.
  • The backlight shall not be kept on without a good reason. It is turned off after a short period of inactivity is to conserve power; therefore overriding the system defaults should only be done if there is a compelling reason.
  • Communication technologies, such as Bluetooth and WiFi, should be used carefully, as there is always some drain on the battery when any network interface is active.
  • The camera has to be powered off when it is no longer used. Even if the camera is not being actively used, it is still consuming power if it is not powered off.


Please, always remember that mobile device has limited battery power. It is not the same as desktop world where the power is "unlimited".

Symbian C++ | Next | Previous | Comments (5) | Trackbacks (0)

Comments

Re: Always Remember that Mobile Device has Limited Battery Power

mgroeber9110 | 24/04/2007, 11:02

I think it might still be worth documenting the application that did it somewhere, not to "name and shame", but because I suspect that there are quite a few undocumented "quirks" in S60 that affect power usage in an undocumented way.

My favourite example are audio streams - if you open a CMdaAudioOutputStream, play some buffers, and then just let the queue underflow (i.e. you supply no more audio data), but do not call Stop() on the stream, the audio hardware stays open, and drains the battery in about half a day.

This behaviour was introduced only with the 6620 and later phones, but to my knowledge has never been explicitly documented anywhere.

So even for developers, the only way to learn about this may be through user feedback, and collecting feedback from the field.

Re: Always Remember that Mobile Device has Limited Battery Power

antonypr | 24/04/2007, 18:20

antonypr That is a good point.
Unfortunately, I didn't do more investigation about that particular application; so I don't know exactly why it drains the battery so far. What I noticed is that my battery life are back to normal after installing it.

Re: Always Remember that Mobile Device has Limited Battery Power

luis-junior | 25/04/2007, 06:14

luis-junior Great topic!
I might say that you shouldn't care about battery's life as it is LiPo (lithium-polymer)...

Re: Always Remember that Mobile Device has Limited Battery Power

stichbury | 24/04/2007, 20:13

It's interesting that this isn't something that Symbian Signed can easily regulate, so the potential for "hungry" apps is still there despite the quality checks performed. I guess in this the criteria CON-01 Task List "The application can be closed through the task list" could cover it, since the server couldn't was running and eating battery - unless you *were* provided with the option to stop it?

If you can't tell us what the app was, have you contacted the creator and reported it?

As complete aside, I had a similar experience with my E61 recently when I went to Europe with a Canadian SIM which wasn't enabled for roaming. I kept my phone on so I could use it to get contacts, set alarms, tell the time etc, even though it wasn't on a phone network. And I left the profile in General. The battery life fell to about 24 hours, even when I turned off bluetooth and WiFi. The reason must have been that the phone kept trying to register on the network. As soon as I switched it to offline mode, all was well again. It was my own fault for not "making the connection" (pardon the pun) and doing so earlier, but couldn't the phone software determine the problem and stop trying to get onto the network after a certain number of attempts?

Re: Always Remember that Mobile Device has Limited Battery Power

antonypr | 25/04/2007, 07:49

antonypr Jo, you are right that there might be a server still running even though we can close the application. I believe this was the case in my problem too. I didn't see application running in the task list. I'll try to contact the developer and see what their comment.
You must login to post comments. Login
 
 
Powered by LifeType 
     
     RDF Facets:
     
     
     qfnZtopicQUqfnTopicZcppQ
     qfnZtypeQUqfnTypeZBlogContentQ
     qfnZtypeQUqfnTypeZBlogE45ntryQ
     qfnZtypeQUqfnTypeZCommunityContentQ
     qfnZtypeQUqfnTypeZWebpageQ
     qmarsZlanguageQUxhttpE3aE2fE2fswE2enokiaE2ecomE2flanguageE2d1E2fenX