When your WiFi is disconnected, it really isn't using a lot of power. It isn't really transmitting much, only sniffing around every so often to find out what hotspots are nearby. The amount of power used is negligible.
I have some personal experience with this.... Back when I had my SIII (and to some extent my Nexus 5), I became obsessed with trying to squeeze everything I could out of the battery. I fiddled with all manners of things using automation apps like Tasker and Llama. One of those was disabling WiFi when it disconnected and turn it back on when I was around a known hotspot. Turns out that toggling the Wifi adapter actually did more harm than good as the power it used ended up being more than just letting it sit there, waiting for something to connect to.
05-06-2015 11:51 AM