I got this post from AndroidForums by jreed2560 so credit goes to him/her:
"when the first leaks of 2.1 for the eris showed up, a lot of users noticed that the battery was draining very quickly on their Eris. a quick check in the battery information screen showed that a process called Cell Standby was the culprit. In most cases the phone showed that it was without a signal 50% of the time. In some cases it was around 70-80. A quick trip into Airplane mode for a few minutes, followed by a reboot seemed to be a generally accepted workaround if you are experiencing this issue."
----My Ally has this issue, I get about 6-7 hours of life on light-medium use, your phone should get about 17 hours on HEAVY use. So if you are reaching 15+ hours than you dont have this problem.
Cool, I will have to try that out. I am definitely not getting 15+ hours of heavy use. Battery life hasn't been too terrible but a little more would be nice. Let us know how your other "test" turns out!
Also check out the app called Power Manager Full. You can extend battery life with that.
A comment on Power Manager Full says, "Don't bother with it if 2.x as it has not been updated to take advantage of current API changes." Don't know if those comments apply to Ally, or not.
Here's a couple of things that have helped me.
1) Use an app killer. Yes, you can just go into Settings>Applications>Running services and stop APS from there too. An app is more convenient. I've been using TasKiller and it works really well.
2) I also performed the steps in the initial post and my results have been mixed. I've seen my phone display Cell standby as 67% and 100% without a signal, but I've still been able to make and receive calls, download and search the web fine.
3) Charging. I put my phone on airplane mode and the battery charged to 100% in just about 2-hrs. Last night was the first night that I ran by battery completely to zero%. Phone was purchased last Saturday, so battery is still breaking in. So far I've been able to get about 8 solid hours out of the phone.
4) Unsure if this does anything, but I read a review for another LG phone (Also a slider) where behind the screen, the factory scratch protector/plastic had bubbled and caused buttons to always be pushed. Slide your phone open and remove the plastic strip behind the screen (The area usually covered by the keyboard when closed).
As I type, my phone is at 67% and 100% w/o signal and I'm searching the web just fine.
My battery lasts about 8 hours under moderate use. I tried airpalne mode fix and my "time without a signal" went from 50% to 0%. but my "android system" spiked from 5% to 90%. any ideas? my battery is draining faster now. I also downloaded an ap called "network" that allows me to bypass the #4 other fix. any ideas?