I have a jailbroken iPhone 3Gs, and it keeps turning off. It will only turn on after I plug it in either to a wall or my computer. After turning it on, it shows the little red lined battery with the "lightening bolt" but then once it actually turns on, it always has most of it's batter full, of not 100%. I can use it all day if I keep using it, but soon as i let it sit for a few minutes it turns off again until i replug it in.

If this helps, I did drop it the other day before any of this happened, could i have jarred the batter loose or something? The screen cracked when I did that, so I ordered a new one that should be here in a few days, i could take a look inside the phone then when I take it apart to fix the screen.

Any suggestions? Thanks!