Should I leave iPhone on charging cradle all the time?

From what you say it sounds like almost all the iPhone use is while it is connected to a power source. If that's so then yes, it will have a negative impact on the battery, because these battery types like to be continually charged/discharged, even if in small increments each time. All it will mean is that your battery will likely deteriorate faster than normal, meaning that instead of dropping to 80% of original capacity after the equivalent of 200 full charge/discharge cycles, it'll drop to that point in less. How much less isn't easy to predict.

Personally, I'd use it at least 50% of the time away from the cradle if not more.

Copied from this link.

http://www.apple.com/batteries/iphone.html

*+For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month.+*

You can leave it on the cradle all you want. You don't have to.

Use it like you would any other PDA phone or your old cell phone.

I'm not sure exactly what you mean. It can, of course, be used permanently connected to power, but in terms of battery condition, that would not be a good thing. Of course, used almost permanently docked, battery life may not be much of a serious concern, but it will be impacted even so.

I dont see anything wrong with what the guy in the first post is doing. I am sure its off charge a little to drive to work, back home, out to lunch, on weekends, etc...

When I get home and after dinner retire to my usual comfy chair, I plug my iPhone in and use it that way the rest of the night. Then when I go to bed, I turn it off and just let it fully charge over night.

From Apple at http://www.apple.com/batteries/

"Exercise Your Machine
Lithium-ion batteries need to be used for maximum performance. If you don’t use your device often, be sure to complete a charge cycle at least once a month. ...."

It's all about keeping the battery working - while also keeping it within optimum operating temperature as much as possible. Using it regularly away from the charger helps with both.

However, it's not as if the day after tomorrow the battery will fail if not used that way - it's that it will slowly deteriorate, with two possible outcomes: 1, that it will hold reducing charge (in comparison to a well exercised battery)over time, or 2, will hold no charge at all - a fate not uncommon with laptops that remain always connected.

As long as a complete charge cycle is performed at least once a month, no problem. This can be 5% one day and 10% the next or 25% weekly, etc.

"I too have two docking stations, one is the dual dock that is provided with the BlueTooth headset and the other is the single dock. I keep the single at home and the dual at work - primarily because I work with patients who tend to frown when I walk in their rooms wearing a pair of white earbud - they think I'm "somewhere else listening to music" but I'm usually online with my assistant dictating instructions or notes. If I use the Bluetooth then the patient just thinks I'm talking to myself and that seems to please them a bit more. 🙂

When home I'm usually at my computer and my iPhone is docked but here at the office I only dock it when the battery needs a boost. If I listen to music I might dock it but not necessarily. I do spend an hour each evening walking to/from the Marina Baseball Park (I coach softball) and watch a movie or TV show on my way home. Once home tho' I'll dock it if I'm not going out. It is always docked when I go to bed.

Tim...

The iPhone apparently has a polymer type lithium ion battery.

These are a bit different than the previously popular nickel-cadmium type. They don't require charge/discharge cycles, so it's best to keep them "topped off". Deep discharges are to be avoided on any battery, generally speaking. They will charge up again, but they will never be quite what they were before. It's easy to slip over the line into silliness, the battery will require replacement in 2 to 3 years anyway to maintain performance, and I really don't think I want to experiment dragging that last 1/2 mAh out of the battery on a $600 phone a few years from now. Keep it supplied with good juice!

OTOH, leaving nickel-cadmium types semi-permanently on a charger is a serious problem because they are often used for critical back-up applications - and they will probably fail despite the "green light". But Li-ion types are reasonably quick at charging and don't suffer from "memory" effects, and have a high capacity for their size.

The battery manufacturer of Li-ion recommends a complete charge/discharge cycle every 30 charges - note this isn't anywhere near 30 days necessarily! So I would tend to go with the battery manufacturer rather than Apple in this instance, (assuming we are talking about Li-ion) Esp. note this has nothing to do with the battery itself but rather the software for the battery indicator on iPhone, according to the battery manufacturer this helps ensure accurate battery life indication.

Lithium Polymer does not equal Lithium Ion... Do a web search, there's lots of info out there...

I posted this on another thread:

Regularly exercise the battery (and keep it cool as much as possible). Keeping that in mind, the ideal situation is to leave the phone plugged in as much as possible. The iPhone uses a Lithium Polymer battery just like the new MacBook and MacBook Pro batteries.

I have a charger at home and at work. I leave the phone plugged in while sitting at my desk at work and while I am at home. The battery gets exercised daily on my commutes and when I'm running around town. Otherwise, it's plugged in and not counting against my total lifetime charge cycles (just like my MacBook). Which, by the way, in ideal conditions should be well above the 400 number. I personally don't feel my battery is at end-of-life at 80% of the original max charge level, more like 40% to 50% original charge level. But that's a personal preference.

Hi.

_"Lithium Polymer does not equal Lithium Ion"._

Certainly not! They are an improvement. But the question here is whether their charging and use characteristics are the same, and they are.


_"Do a web search, there's lots of info out there..._"

I did, and found that there is a lot of mistaken and/or garbled information being put out, even here on the Apple forums!

Interestingly battery technology in the Li-ion field is changing rapidly - every few months, and the total lifetime capacity of the latest series of batteries isn't known yet. They may well work "fine" after 3 or 4 years, or maybe not. Probably not.

Still, they have similar characteristics with respect to charging. "Regularly exercising" the Li-ion battery is not necessary nor even desirable, EXCEPT to keep the battery indicator/software functioning reasonably accurately on the iPhone itself. This is where I choose to follow the battery manufacturers specifications, notes, cautions and recommendation versus third or fourth hand information from general owners of the device that uses it. I think that makes a certain amount of sense, wouldn't you agree?

For example, it's commonly stated (here) that iPhone users should "discharge their iPhone all the way to zero at least once a month to keep the battery healthy."

What does the battery manufacturer say about this? They recommend a full discharge every 30 charge cycles, which isn't anywhere near 30 days depending on the use level! They go on to say that the battery is quite happy in a mostly charged state - but that the battery indicator will become increasingly inaccurate over time if the discharge is not performed periodically.

According to the battery manufacturer, there is no "memory" with Li-ion, nor are long "priming" charges necessary. (This is why it's OK to leave it on the charger semi-permanently) - any battery is degraded by a full discharge condition. This is especially true with lead-acid type batteries. Oh, they will charge up again - but they will never quite be the same. Trolling or "boat" batteries are designed around this problem.

The point I quoted about Ni-cads is an important one - lots of research by industry (people who use radios/cells and other rechargeables) found that light use over time and constant charging counterproductive - when the item was eventually called upon for a full duty cycle, they failed right away. Oops. Li-ion are advertised as immune from this problem.

For the folks who are complaining about the expense of replacement batteries down the road, consider the value of rechargeable packs - how much are those 4-packs of "AAA" cells right now? 5 bucks? That would add up awfully quick.