Can anyone say with any authority whether it is possible to overcharge the Iphone 3g battery. I have seen different opinions, but nothing authoritative. Some suggest that the Iphone has sophisticated battery circuitry that goes into trickle charging after the first two hours and then when the battery is full, switches the charger off. Can anyone confirm this?
Many thanks...

Well granted you can't overcharge any of the other recent Apple products, I don't see how this would be any different.

It stops charging once full.

You can leave it plugged in via USB or AC and it stops.

It is impossible to overcharge a battery via a charger with nearly any gadget on the market today.

The iPod touch (so probably the iPhone) charges 80% of its battery in the first hour, and completes a "full" charge in 4 hours, according to Apple. This is because of the nature of batteries, as they become more charged, their resistance goes up and so they charge slower. This makes it impossible to overcharge a battery. When people say they overcharge a battery they generally mean they put to higher current in the circuit or similar.

Would it be ok to leave your iPhone charging 24/7? That still wouldn't wreck the battery?

I think that's what has happened to my Macbook Pro, it has been charging in my room for a few months now, I never turn it off because I have it hooked up to my TV and I use front row every night until I fall asleep. I probably could turn it off when I wake up, but I never do.

Anyways, my point is my Macs battery used to last 3 hours and now it only lasts 1.5 at best.

It's not even 18 month sold.

When your battery is full, it switches from battery power to AC power. Its not a case of it draining to 99% through use, and then recharging to 100%. Once its full, its full

Have a read through Apple's recommendation for conditioning a battery. This supposedly re-calibrates your battery.... and maybe will get some more life out of it.

I did it recently with my MacBook Pro and now when it's plugged in it says "(Charged)" up top and doesn't continue charging. It never did that before, that I noticed.

My MBP currently says charged too.

It's just that I think I may have wrecked the battery life by keeping it turned on and plugged in 24/7.

I'll have a look at re-calibrating the battery though.

If its turned on and plugged in all the time it doesn't use the battery for power, it draws it directly over the power cable.

Cool. I was wondering this too. I just purchased the 3G dock and have it connected to a power source. When I come back from work, I just whack it in the dock and let it charge.

I know there is no "memory" cycle, but is it wise to just charge it when only a little bit has been drained/depleted everyday? I am trying to run the battery dry at least once a month...

One cycle can be done in various ways.

If you drop from 100% to 0, back up to 100%. That's one.
If you drop from 100% to 99%, top up to 100% and do that ten times. That's one.

See what I mean?
If you keep plugging it in daily (which is what I do too) even though you've lost 5% or whatever it is... it isn't one cycle, it is a fraction of a cycle.

Perform a few fractions and you've got a whole number.

I also charge my iPhone daily/sync and every then and again I let it drop to 5, 10-20% (red) before topping up. I've been doing this for over a year with the 2G iPhone and again with 3G no problems.

Had it for over a month now (3G).

Thank you. Nobody really explain to me a cycle really is.

Until I got an iMac, I had been using an HP laptop for about 4 or 5 years. In the beginning the battery was good, lasted about 2+ hours. But I left it plugged in to the electricity for a long time without using the battery alone.

Now, if I try to use the laptop on battery I might get about 20 minutes off the battery.

I don't think this applies so much to iPhone's or iPod's (different battery types maybe?) but with laptops I now know that it's recommended that you use the battery every so often. Let it run down all the way and then charge it all the way up again. Also, if you are not using the battery (ie. using AC power for long periods) then take the battery out. This was suggested to me by either a Microsoft or an HP tech a couple of years ago.

I've always ran my MacBook on AC, and hadn't noticed much difference. I do run it dry once a month. And I think I managed to get 3 hours watching movies on a full charge of battery.

Anyway, the iPhone isn't meant to last more than a few years anyway! I think by the end of it's battery cycle (I am guessing 2 years), a new one would come out, my contract would have finished and I would upgrade to iPhone 3/3G