It seems that my iPhone 3G stops charging when I power it off. Sometimes it will fully charge when I power it off, and sometimes it doesn't. What could be causing this? I'm using the wall charger that came with the phone.
You know, maybe you're right, but I could have sworn it has fully charged when powered off in the past. Last night I was down to 10% battery. I plugged it in, shut off the phone and went to bed. When I turned it on this morning it was at about 50% battery, so it did charge a little while it was powered off, but only half way at most.
Why not just turn on Airplane mode? Does it harm the phone by having it in sleep mode? Why do people turn them all the way off? I don't think the iPhone was meant to be turned off... just sleeping. It's better for the battery to keep the iPhone on and always charge even if the battery is hardly moved.
On a regular night I put airplane mode on and plug it in. I think of the night I turn it off a break for my iPhone. Not that it needs one. It's more of a break for me so that I'm not on it all the time on that particular night. I just put it away for a little awhile. It's not harmful both ways. Asleep makes no difference to turning it off, I just do it by habit and preference.