Android GPS Power Saving
While I've been playing with my auto-speed app, I've been flattening the battery pretty quick (not a problem in real use as I'll have it plugged into car charger).
Anyway, I've been religiously switching GPS off when I'm not using it but only discovered today that the OS does this for me :)
Basically, if no app is using GPS - it switches it off - and then switches back on if needed again.
Suuposedlty, the battery drain only occurs if the GPS is left running in the background but you can tell this my just looking for the GPS icon and either manually switching off or closing the app using it.
I haven't done a series of tests to see if this is all true but it sounds good anyway :)
(Should saves a bit of faffing when getting in/out of car :)
I use the GPS when out walking and have had it on for 7+ hours and it probably uses around a third more of my battery life than normal use. Still pretty good considering it uses Google maps including satalite view. When I get a chance I'm going to see how long it lasts with GPS on full time :D