Wifi auto reconnects when I dont want it to

Wifi uses less battery than 3G. Also, if you have low-usage data plan, you *want* to default to using wifi.

Don't change it or both your data usage AND your battery will suffer.

If you want to, you can shut off wifi when NOT in the vicinity of a known wifi source.

Even then, it's been reported there's negligible battery drain even if you leave wifi on all the time.

I personally keep my wifi off when away from home. But I use Tasker, which turns my wifi on and off automatically, so I don't even think about it.

 

Settings > WiFi Settings > Options Button > Advanced > WiFi Sleep Policy. Only way I've found around it.

 

Agree with both of the posts above. If you really want to turn it off, it sounds like your Wifi Sleep policy is causing the behavior you noted.

However, Booklover is correct and you should reconsider turning Wifi off if the alternative is maintaining a 3G connection.

That said, if you want to have both 3G and Wifi off that will use even less power (of course)