So I had a jailbroken 3g. Everything was going well but my battery started to drain very fast.
I'd leave the phone in my pocket during school and it'd be dead by the end. I'm wondering
if it's just the charger I have(Which I'm going out to buy a new one) or because cydia or
another program is running in the background which is killing my battery.

And yes, I've done all the things necessary to preserve battery like turning down the brightness,
manually fetching data, turning wi-fi off, etc.