Originally Posted by
tech_head Just leave it on.
It does not draw that much power when not connected. It's very low power.
I just leave mine on.
You will need to have an NFC tag or something.
Typically you use bluetooth status to trigger an event.
You could use GPS if it was location based.
You want something to detect when you are in your car to turn on bluetooth for the car..
Chicken and egg......
I used to manually turn my BT on when I got in the car; I had AutomateIt set to turn it off when I connected to my home wifi.
After doing that for a long time I recently decided to just leave it on and see how my battery life was affected. Doesn't seem to have any impact at all so I'm just leaving it on along with the Wifi. This phone has the best battery life of any phone I've had. I can easily make it through a day but I have a back up battery just in case.
It really surprises me how many OEMs are fixing the battery in the case. The battery life is no where good enough for that IMO. I have to have a phone with a removable battery.
I did use NFC tags with my Galaxy Nexus to turn BT on and off but it was more of a hassle than it was worth.