What is active GPS effect on mobile devices battery life?

How much does active GPS drain the battery? Without the over开发者_如何学运维head of the gps navigator software. s ay I want to sample the gps every 2 minutes and save it to a file. how much battery power will that cost me?

Will I get 10% shorter life? 20%? ..?

I think this can't be answered that easy without measuring it. But you could measure it. Just try how long it takes to empty the whole battery. Once with GPS and once without.

It will be noticeable by the user. You definitely don't want to do this kind of thing unless it is a feature the user is explicitly aware of and able to clearly turn on and off depending on whether at any particular time they think that feature is worth the impact on their battery.

On my HTC Desire, RunKeeper with GPS always active, battery was near to down after about 5 hours of usage (in forrest).

But the screen was down while it was running, 2 hours of reading pdf drains about 40-50% of battery, so GPS working in background drains about same or less energy than screen active.

When you turn the GPS on, you must wait, depending on where you are, before you get the read, so if you want to save position every 2 minutes, I think GPS will be on about 25%-50% of time. 10 hours of work in background would be max in that case...

Maybe the question about increasing battery life on Windows Mobile using GPS will give some hints, since the device used in test was manufactured by HTC, which is one of the most popular manufacturer of Android Devices nowadays...