Looks like it was the cellular radio using up the battery rather than the wifi. Not all phone features make use of wifi, and the phone is constantly searching for or communicating with a cellular tower for various purposes.
Ok so if I understand it and correct me if I am wrong, the wifi would be more for data on the phone and the phone still is searching for a good signal from a tower via the radio and not doing calls over wifi?
That is correct — at least for my phone. Obviously, if you want to make sure as to which way the data goes, you would have to turn off the cell connection. For my phone, when I put it in airplane made, that turns off all connections, then I can turn on the individual connections that I want. But, with both the cell and wifi on, data requests go thru any established wifi connection, and the cell connection is still used for phone calls and sms messages.
Bottom line tho — each of those connections you have on, you are adding the the battery drain.