The batterylife of the iPhone 3G is not so good. Many threads have been posted about this. But I've got a very specific question regarding pushing or fetching MobileMe services and doing this using wifi or 3G. Please hear me out... I use the iPhone with MobileMe’s push functionality. Where I live (the Netherlands) my 3G reception is excelllent (full bars). However, I do have wifi turned on. Apple states on its site that the phone will last longer using wifi than 3G. However, that’s using Safari to browse the web. I’m curious about the battery impact of push and pull (or fetch) email. I can find on the web that in general push is more battery efficient, than pulling on a high interval. Only which interval is that? 15 minutes? 30 minutes? I don’t know. But coming back to the first part. I’m also wondering whether push using 3G is more power efficient than through wifi. It seems to me that it has to connect to wifi every time, while the 3G connection is there permanently. So that’s using power anyway, while wifi is sucking up additional power, especially on very low data-consuming services such as MobileMe’s push functionality. I’m doing some tests on my own iPhone. However, it’s hard to compare. Because I’m using it as my phone, I cannot create identical conditions, which makes the results more or less worthless. What I've found out so far, is that there seems to be a slight edge to turning wifi off, to increase batterylife when using pushmail. I'm currently testing fetching email every 30 minutes. However, this is only for the purpose of testing, since I'd rather use pushmail (and contact and calendars). What are your thoughts about this?