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This is not true.

Once the battery is fully charged, you'll notice the icon in the upper-right changes from the lightning bolt to a plug. That means the phone is running on power straight from the outlet. You can't "overcharge" the battery.

For a more in-depth explanation of all things iPhone battery, see this thread: https://forums.macrumors.com/threads/525741/

What I'd it shows the plugin sign and my percentage is at 98%? It has went down from 100% to 98% and I've left it plugged in.
 
i went into an at&t store this past fall and they told me u can hurt ur battery.

They said it depends on the charge. They said certain chargers do not have the proper chip build in to prevent multiple recharge cycles.
 
I got my iPhone 3G the day it was released and have never had a battery issue with it. I use it all day long and at the end of the night put it in the Apple charger base and it sits in the charger all night long. When I am at home it is also usually in the charger base if I am working on the computer. I also carry a charger plug with me in my backpack for the rare occasions where I may need to recharge. I have probably only needed to use the plug for that purpose a few times. Mostly I use the plug to sync the iPhone with the computer. At this point I've had the iPhone for over a year and a half and have not experienced any degradation of the battery at all.

With the new iPhone expected in June or July I don't think I'll see much degradation, if any, before then. Unless the batery completely fails all of a sudden I think I can live with it a few weeks or months until the new iPhone is launched.
 
i went into an at&t store this past fall and they told me u can hurt ur battery.

Yes! Because when I have hardware issues with phones, electronics, etc. I go to my at&t store with my questions and expect the best, most correct answer EVER!:rolleyes:

/sarcasm, don't take an at&t rep's advice, EVER
 
Yes! Because when I have hardware issues with phones, electronics, etc. I go to my at&t store with my questions and expect the best, most correct answer EVER!:rolleyes:

/sarcasm, don't take an at&t rep's advice, EVER

wait.... so when ur phone is malfunctioning u take it to the maker? Huh... I have a Palm Treo on sprint... im not sure where a palm store is.... I have always just taken it to the sprint store and had them work on it. They always seem to know what they are doing cause the problem always gets fixed... "seem" being the keyword.

sarcasm. Sorry. Had to do it.
 
Last time I checked, Sprint ≠ AT&T. I'm not sure if you've had any experience with AT&T's reps earlier than your little "visit", but they aren't the sharpest crayons in the box. If you had problems with your Palm, I'm not sure what would have been so difficult about calling them directly. I'm just the person who would rather not waste money driving to the store and would rather call the manufacturer directly.
 
I have an iPhone 3GS and i have been looking for answers about this, i have some time with the iphone and i found out that is better not to let the battery percentage go below 40% before you charge it again, if you let the battery drain it will be bad for your battery lifespan since this is bad for lithium-ion batteries, i've heard that when The iPhone is plugged in the charger it does not use the battery at all but uses the AC power from the connection and it is charging the battery at the same time, i don't know if this is accurate.....

The one thing i know is that it doesn't matter if you keep the iphone plugged in the charger, it will recognize when the battery is full and will not overcharge or overheat, but it is recomended not to keep it connected more than 12 hours because it will still be charging from time to time 1% or so
 
I have an original iPhone and macbook whose batteries are in pristine condition after 3.5 years (ie. they pretty much still act like new - esp my iPhone which I must say I'm quite impressed - best rechargeable battery I've ever owned!)

When i asked about laptop batteries at the apple store they specifically said that leaving the laptop plugged in basically causes repeated charging cycles and WILL actually reduce the lifespan of the battery.

I kept my macbook plugged in while "docked" at my desk traveling with it several times a week for the first year. Over the past 2 years, it pretty much stays home and stays plugged in.

when I go out into the field 3 or 4 days a month, the macbook is used sufficiently enough for it to drop to almost 0% which keeps it in better condition (ie. it is a good idea to completely discharge the battery at least once a month)

the only conclusion I've come to is because the light on the plug is almost always green, no cells are ever charged when it is at 100% thus not damaging any cells.

if the iphone battery is anything like a laptop's, I would think it could be an issue.

I thought the same thing to be true in the reverse. For the first 3 years, my iPhone had been discharged daily and charged nightly via USB. It is only in the last 2 days I decided to leave it plugged in 100% using a wall outlet (to use an app that requires I turn off auto-lock)

It gets noticeably warm which is my concern.

anyone know definitively if the original iPhone
  1. has a circuit to stop supplying juice after it hits 100%?
  2. changes [battery charging] behavior whether or not auto-lock is on?

for the record: the iPhone is in Airplane mode and WiFi and bluetooth are off
 
For what it's worth, I've left a 2nd-generation iPod Touch (2009) plugged in continuously for months on end with no adverse effect on the battery. It wasn't even turned on once during all that time. The first time I turned it on, the battery discharged completely in less than an hour, but after a full recharge it worked like new again.
 
before i replaced my iPhone 4 32gb i had the thing for about three years. my girlfriend (at the time) and i were both new to the iPhone world and were doing as much research as possible.

aside from how you charge the phone, whether or not you draw a lot of power from it allows the battery to last much longer. i, unlike the other posts here, never allowed it to go to 0% (although i believe its something I'm going to try doing) and i experienced amazing battery life overall. it didn't noticeably start losing charge life power until i bought my new iPhone 5s 64gb in april 2014.

so certain things i did was (although others don't seem to mind it) i always unplugged the thing if it hit 100%, i found no reason in allowing it to stay plugged in past full charge. in addition, if you're connected through your wifi and the phone is sleeping (screen off) it'll stay around 95-100% for hours on end (if you don't plan on using it) so i don't see much point in leaving it plugged in to make sure you have a lot of battery.

also, don't ever use 3rd party chargers. always use apple materials. i find it pertinent to not give your phone a reason to hate you.
 
First of all, you will find countless opinions of "the best way" to maintain your battery, whether it be a phone, tablet, or laptop battery. In my humble opinion, if you just use common sense and use the battery as a normal person, you will not notice a difference in performance.

This is not to say that a number of factors do not affect battery lifetime. But in the long run, you will not gain much by being the "perfect" lithium-ion battery owner. The difference will be miniscule.

With that being said, leave your device plugged in as much as you want. Some say that is bad, and that you want your battery always within its "happy range" of 15-85% or some BS like that. Here's a personal anecdote: I've owned an iPad for 3 years. I also work every weekday. I don't bring my iPad to work...no need for it. I use it on the weekends and after work. The rest of the time, the iPad is on the charger. When I use the battery, I notice absolutely no degradation of the battery as compared to when I first purchased the iPad. In fact, the battery life I get on my iPad still impresses me and I am more than pleased with it.

In short, just use your device like a normal person and don't worry.

*Disclaimer: there are some common sense things to worry about, many of which were already mentioned, including don't leave your device in the sun, and be wary of 3rd party chargers since the amperage might differ. One more item that may not be very common sense but is important is do not use car chargers...the voltage in a car charger fluctuates when you start/stop the car and accelerate/stop accelerating, and the voltage jumps are very bad for the lithium battery.
 
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