I just read this article in my researching the battery drain problem reported by “upgraders”  (ie from the 3gs)

At the end of the article,  some “battery life tips” are basically irrelevant to this problem,  which is that 3gs users who have upgraded to iOS4 have IMMEDIATELY experienced a stark contrast in battery life from what they had prior to the upgrade.  For example,  I basically never turn off my 3gs since getting it in November.  The only times it has been off is on the rare occasion (maybe 3 times in 7 months) when I have had a lockup.   If I go to bed with a 100% charge on my phone,  sit it on the table next to my bed,  in the morning it still has 98-99% battery.  Last night it fell from 100% to 66%,  no calls,  no nothing.  I read one article that suggested turning off email account PUSH.  So I’m trying that. So far, so good.  38 minutes have gone by,  and the phone is till at 66%.

The following “tips” ,  apparently suggested “solutions” for this problem,  are irrelevant to this OS upgrade problem.

Tips for better battery life

While the issue gets sorted out, with rumors of a potential software fix in the mix, there are a number of ways Apple recommends extending battery life on its iPhone and other devices.

Top on the list of Apple’s tips is keeping the iPhone out of the sun or a hot car. The phone works bests between 32 degrees Fahrenheit (zero degrees Celsius), or freeze point, and 95 degrees Fahrenheit (35 degrees Celsius), or just plain uncomfortable.

Never have done this,  so IRRELEVANT

Apple also recommends making sure the phone is updated with the latest Apple software because their engineers are always looking for ways to use battery life more efficiently.

Always done this,  so IRRELEVANT

Other tips are to optimize your Phone’s settings, such as turning off Bluetooth if you rarely use it or maybe lowering the screen brightness just a tad.

Bluetooth is and has always been OFF,  so IRRELEVANT

Worst-case, iPhone battery replacement is an option if a presumably older device can no longer hold a charge. Such replacement might fall under a warranty or protection plan for free, but otherwise getting a new battery costs $79

Battery has been fine,  and was immediately before the upgrade.  

Battery lost a percent after 40 minutes following the aforementioned settings change (turning off email push).  So I will presumably lose 10% or so overnight at this rate.  Still a problem,  given that the loss before was 1-2%

Is the New iOS4 for the iPhone 4 a "Power Vampire" that is Draining Batteries? | TechNewsDaily

I’ll be interested to see what is discovered. 

Maybe I should “hold it different” and “lay it on my nightstand different”