Forum: General Topics
I was just wondering if anyone had done any experimentation on battery life/drain whilst using TMJ.
Any ideas, what would the relative drain in the following situations be (I've put them in order of what I would guess to be greatest to least).
1) TMJ with bluetooth switched on and web-access running
2) TMJ with web-access disabled, but bluetooth on
3) TMJ with web-access disabled, bluetooth on, but the GPS device switched off (eg whilst indoors)
4) TMJ with web-access disabled and bluetooth turned off.
5) Phone in standby (TMJ not running).
I'm most interested in any differences between 2,3 and 4. Wondering how to conserve battery life during breaks/when indoors with the minimum amount of faffing around with my phone.
In general I think I agree with the order that you've listed the situations in, although a lot of this would come down to individual phones and how they handle their own energy savings.
- Some phones maintain the web connection constantly (I'm thinking BlackBerry here, maybe others), so TMJ transmitting every 5 minutes or so is unlikely to have a massive effect on battery.
- Web access energy use may vary depending on 2G or 3G, and can also be worse in low-signal areas where the phone has to 'shout' more!
- Bluetooth is pretty energy efficient, but disconnecting from the GPS will help a little (if you don't need it at the time). One point here is that on SE phones you should use the TMJ Menu/GPS/Disconnect option (unless exiting TMJ altogether), rather than just switching off the GPS device. This is because TMJ will otherwise keep trying to connect to the GPS every few seconds, which will use a burst of bluetooth energy each time.
- Backlight off, obviously...!
- Running TMJ in 'minimized' mode in the background can also help significantly - the screen rendering on most phones only occurs when the app is in the foreground. There should probably be a step 4.5 in your list to account for this.
- Scrolling around the maps (both vector or raster) can increase the memory use and memory card read/write activity, so might also affect energy use.
In your scenario of conserving battery life when on a break/indoors, to make things easy I would probably leave Web Enabled, but tick Web/Only Send on New Trackpoint. Disconnecting the GPS should then effectively disable web as well since no new trackpoints will be created (but scrolling the map will still use the web if its not already cached). Then minimise TMJ (on the K770 press the hangup button and possibly then select Minimise). You may also be able to set a home-screen shortcut to automatically maximise TMJ, simplifying startup...
Failing all that, I generally have a mini charger on me if I'm out for a while, just in case - a day out without the car will generally involve a pub stop at some point, who usually seem quite relaxed about the use of their power points (or should that be power pints)!!
I haven't performed any official observation or made any records, but I have noticed that on my Nokia E52 TMJ is the application that uses less power then any other. I usually used it with both WEB and Bluetooth GPS on and backlight on while driving. For my last journey I was very surprised that for around 2 hours and about 130 km driven I haven't even used 1/4 of my battery! As you know many factors are important like battery age and I also it's very important whether the WEB access is over 3G or 2G/GPRS!
I can say from me experience. I used many map apps, eg. Google Maps. I can say that TMJ consumes the lower power amount.
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