those of you who manage to make it last for over 20 hours, how do you use your phones?
I usually get over 20 hours with mixed use. I can go just under 30 hours if i'm careful.
First things first, i downloaded Gingerbreak and rooted the phone. Then i got Titanium Backup and backed up some stuff then started uninstalling LG apps that i don't need. like Finance and SNS, which has the Facebook, Twitter and Gmail apps.
Then i disable GPS and location tracking. Disable Wifi and just turn it on when i want to use it. I turn off background sync and mobile data. I dont have anything using internet in the background. I update everything manually. I only use 1 widget and that is Memo, the built in notepad because i think it's useful for me.
I usually have the screen set to 50% brightness but sometimes higher outside in the sun or when i want to show off
Most people think the screen is awesome, bright and vivid. Even Iphone 4 guy at my work loved it. When i'm doing something like working and know i won't use the internet on my phone i switch it to 2G only. It save alot of battery.
LG Black is never going to last many days, because it has a bright screen, 1ghz CPU and high resolution. If you want better lasting battery, go with Optimus One with same battery size but only 600mhz CPU, less bright screen and crap resolution.
Right now i am trying out an app called CPU Tuner and it is supposed to save battery by adjusting CPU speed and other things. It needs root.