Why does GPS suck so much battery?

[kfergiez]

So, I'm just curious as to why the GPS location services suck so much battery? My Garmin etrex vista takes two AA batteries, and has stayed running for a full day of hiking, plus the next day, and the day after that. That was something like 22 hours of constant usage.

Even on the box of my Garmin it has listed somewhere around 20 some odd hours of battery life.

So, if my garmin can stay connected to GPS satellites for that long, why can't my phone?

 

[Applejuiced]

Maybe because your garmin is bigger and just does GPS?
And you iphone is a cellphone, with GPS and tons more things.

 

[chr1s60]

Using GPS on the phone makes it work harder. Your Garmin is meant for GPS and that is all it runs, which is why the battery lasts so long. Using the GPS on the iPhone means that on top of all the normal operations (cell signal, screen power, and any data you may be transferring for emails or apps) the phone also has to be constantly using data to update your maps application, as well as powering the GPS in order to constantly recalculate your position. I would also guess that the screen on your Garmin requires very little battery power to operate compared to the iPhone. From my experience, the GPS on the iPhone works much better when used in a car where it can be plugged in. For use away from a power source you may want to consider a backup battery or a case with a built in battery.