Doesn't appear to be a battery problem - iPhone 3GS
20 - 30 minuten
The iPhone only turns on when connected to a power source (wall or computer via USB). If I unplug the device while it is on the iPhone immediately dies. When plugged in and running via wall power the phone comes up and says it needs to be connected to iTunes. When connected to iTunes it says it is in recovery mode and needs to be updated which never succeeds.
I attempted replacing the battery since it appeared to be the more reasonable cause. iFixIt had fast shipping and the product was as marked. Very happy with the iFixIt experience however after replacing the battery the iPhone still has the same problem. I left the battery to charge overnight via wall power but still no change.
I assume this is a circuit board issue at this point. I've checked the battery connections and ensured that it was making good contact. I've tried another battery and no change. Thinking this may just end up being spare parts at this point.
I purchased a battery from Amazon that was cheaper however it showed up being the wrong model number leading me to purchase from iFixIt. While the battery didn't fix my problem I do recommend purchasing via iFixit. Fast and accurate product delivery!