i can tell my battery drains a lot faster in 2.2
At first- yes, it drained much, much faster. Then I logged out of the facebook app (as little as I use it, no big deal to log back in when needed, or use mobile site) & adjusted brightness back to 50% (setting had reverted to 100% after manual 2.2 update). Now it's even better than on 2.1. Certainly no problem getting through a full day of fairly heavy use.
Mine is better as well. The first full day I was on 2.2 it was noticeably worse, I had updated facebook at the same time, but didn't like the new look so I reverted back and that fixed my battery issue. Now it lasts a lot longer.
I have done 2 more things to increase my 2.2 battery life...
First I use the SetCPU app to control my processor speed - so it isn't always running at the same Mhz....
Second: I use the free JuiceDefender app.
The combination of these 2 apps increases my battery use during the day dramatically.
The other thing I do is use the stock "running services" NOT any market apps like task killer, etc. I found the market apps burn my battery. I leave the Running Services widget on my front desktop - and several times a day check what's running in the background and it I don't want or use it anymore that day I turn it off. You'd be surprised at how many apps stay 'running' in the background once you 'close' your app.
This mighty combo of 3 things has made my battery life extend dramatically.
A couple of caveats. At home I have wireless so that's what I use on my droid. This alone saves my battery over 3G.
If you live or have your phone in an area that is trying to keep a stable internet signal - no matter what you will burn through your battery.
I just got back from visiting with my family in a rented beach home that had virtually no cell coverage. My phone burned through it's battery in about 4 hours before I realized it. So I had to practically keep my phone plugged in the whole time I was there. Once I got out of that tiny dead zone - battery performance jumped right back up.
So you see there are alot of factors involved in battery performance - hope some of my experiences help answer your questions.
My battery lasts longer with FRG22, and using "OverclockWidget" (free) to under-clock it when it's in sleep mode/screen off, and over-clock to 400 Mhz min / 1 Ghz max when it's running.
I also installed P3Droid's low voltage kernal, and after an hour of watching video/internet surfing in the sun (95 degrees outside), I only used up +/- 20% of battery juice with a max temperature of 120 degrees.
I'm pretty freaking happy with 2.2 and my Droid!!
I experienced the exact same issue. Charging would take at least 8 hours, and the phone would be dead within 3 hours. I was running Advanced Task Killer, uninstalled it, and had the same issue. I had not ever started the FB App, but it was running, and I stopped that. I also tried reducing the Exchange sync frequency. Even still, you could practically watch the gauge go down, and the phone was incredibly hot. You could leave it dark for 60 minutes, come back, the phone would still be hot and you'd have lost at least 25% of the battery. It was so bad, it reminded me of my old HTC Titan running WM6. :P
After backing everything up (Astro File Manager is an easy way for that), I performed a hard reset and data wipe. I did have to re-activate the phone, but since then 2.2 has been running fine, and I am holding a charge as well as ever. Exchange is on push, ATK is still not installed, and everything seems OK. I'm going to slowly go back to playing around with my settings and see if I come across anything else that might have been causing the drain.
The build I am showing is: FRG01B
Hope this helps someone!
I manually updated to FRG01B and have noticed a significant increase in battery life. Yesterday I used bluetooth audio and GPS during a 25 minute run (Cardio Trainer app), wifi for about an hour at lunch, then heavy web and phone usage throughout the day, facebook and twitter apps, and 16 hours after taking off the charger, I was at 40% life. Have achieved similar results each day since updating and couldn't be happier with 2.2. I should note that I wiped the phone before updating so there may be an app or two that didn't get reinstalled.