Originally Posted by E-Phone
One way to test this is to have "Wi-Fi on" on one day and "Wi-Fi off" another day and see how much more is used on the day the Wi-Fi was on.
So today I decided to do just this. Normally I do not leave Wi-Fi on unless I'm going to be using it - really just a few minutes a day most days. But today I turned it on shortly after unplugging the 8900 after it's nightly charge and left it on all day long. Today was a more or less typical day - normal email volume, some texting, several phone calls but nothing too long. It's now the end of the day and I have had both Bluetooth (my car connects via Bluetooth and I often transfer a call to a Bluetooth headset when I get one so I have always left Bluetooth on all the time) and Wi-Fi on all day long. I now have 70% of charge left which is just about typical for a day like today.
In other words - though in theory I must believe that running another radio will drain the battery faster than not running it, I honestly can't see any noticable difference in battery life.
The phone is an AT&T 8900, 18.104.22.168 OS.