2 out of our 3 iPhones have faulty batteries

We've been running extensive battery tests on our iPhones over the past few days, and we've found something interesting; 2 out of the 3 iPhones that we have seem to have faulty batteries.

Our testing involves a lot of charging the phones, then running them down and charging them again. And we found that 2 of the 3 had significantly lower battery life than the third; this is why when we first published our results for the iPhone battery life, we found that the battery life was just 4 hours. We'll be publishing revised results for the iPhone in the next day or so, but after we had charged and exhausted the batteries on our phones several times, we noticed this: 2 of the phones never reached full charge. See the photo below; you can see if you look closely that the two left phones that the battery bar has not reached the right, and the battery icon is not glowing like the one on the right.

Here's a closeup of the three icons.

As you can see, the two on the left are not fully charged. The one on the right is fully charged, and has a healthy radioactive glow that shows it's at full capacity.

All three iPhones have been left charging for at least 12 hours, so the issue here isn't that they haven't had time to charge; Apple says that the batteries should be fully charged within about 4 hours. What we think is happening is that there is a fault in the phones that means that they aren't getting fully charged; it isn't clear if the battery is a fault, or the charger or the circuitry that controls it. These two phones also have much shorter battery life than the third one; in all of our tests, the third phone has lasted much longer than the other two.

We aren't the first people to notice this; this discussion thread on MacRumors is filled with people who are having similar problems, and a lot of people we have spoken to have had similar problems; many iphone buyers have told us that they have returned or swapped out their iPhones.


All of this begs the question: is there a widespread problem with the iPhones batteries?

We are doing some more research into this, but our experience so far indicates that there may be; two out of three phones having faults is a serious problem, and our  research so far indicates that we aren't alone in this. To be fair, Apple seems to be quite willing to swap out faulty phones; everyone that we have spoken to who has taken their phone back says that Apple has swapped out their phone without complaint, and we'll be trying to do that soon with our phones.

UPDATE: We are running a survey on this issue: you can tell us if you have had similar problems here.