Can use ipad charger to charge iphone?

Hi David and everyone,

thanks to all of you for helping try to solve some customers' problems.

I do not write very often and have very limited knowledge on the issue so I apologise if what I write my hurt somehow somebody's sensitiviy.

I have recently bought a new iPad mini and before charging it I wanted to be sure what to do since the the guy at the shop told me "never charge an iPad with an iPhone adapter but it's ok to charge an Iphone with an iPad adapter". After having read half of the internet I decide to ask the advice of an Apple advisor.

It turns out that they don't know much about it. I asked him if I could charge my iPad with my iPhone's 5V charger and if I could charge the iPhone with the new 12W charger. His first answer has been:

- First off the iPhone 3G uses a 10V charger. Don't use a 12V on it because we don't want to risk frying it. As for the iPad mini I'm taking a look to see if a 10V will fry it. Bare with me about 2 or 3 minutes please. [...] obviously 5v will charge slower then 10 or 12v. But whatever you do don't use a 10v or a 12v with that mini.

He also told me: to be sure follow this link iPad: Charging the battery

So I told him: If this is the case why is apple selling this adapter saying is good for the mini?

http://store.apple.com/us/product/MD836LL/A/apple-12w-usb-power-adapter?fnode=74

His answer was:

- Awesome. Looks like we have a new adapter to handle the voltage variances and can detect it. If you are getting that specific adapter then according to the tech spec it will work. It doesn't have the model on there to compare with the models that are on that page. It looks like it's different but as long as we sell it and it says right on the sales page will work with the mini then it will work with the mini. What I'll do is pass that reference article up to clarify it a bit as it is a bit confusing. The sales page supersedes my articles since not every article gets updated immediately. Our page does clearly state that all the 5w adapters are compatible with the mini. It looks like we have a new 12v that will work too. I don't think you should be concerned with charging it if you are 100% certain the adapter is a 5w adapter.

So I now turn out to you. I have an iPhone 3gs and an iPad mini. Can i bloody charge them with the same adapter, i.e. the A1399 model, the last one on this link iPad: Charging the battery.

I am exhausted! Argh! 😀

I know. I need the notifications to see if anyone finds anything wierd with the charging itself not discuss about how Apple can buy lawyers and make their own rules.

The question was:

Can use ipad charger to charge iphone?

Please correct me if I am wrong and this will be my last post on this thread.

Thanks,

Ajay

You can use the iPad charger for the iPhone. They are both the same voltage. The iPad charger can supply more current than the iPhone charger, but each device only draws what it needs. The iPad can use up to 2.1 amps at 5 volts. The iPhone charger can supply only one amp. So the iPad will charge twice as fast with the iPad charger because the charger is capable of supplying that power. The iPhone will also draw what it needs, but that is 1 amp. Even if you put a charger capable of supplying 100 amps, the iPhone would still only take the 1 amp it needs.

The video that has been posted many times demonstrates that: http://www.youtube.com/watch?v=DC4gPxc89Wg

Apple says you can use an iPad charger with an iPhone: http://support.apple.com/kb/HT4060

So unless you believe that Apple is lying so people will use iPad chargers with their iPhone and thus burn out the iPhone so they will have to buy new ones (the "tin foil hat" brigade?) you can safely charge your iPhone with an iPad charger. I would recommend that rather than buying a 3rd party product of unknown safety and capability.

BlueBay wrote:

Would it not make more sense an Apple guru gives us a clear answer to support their products? Apple silence is already not a good sign...!

ARE YOU BLIND? Apple has stated it quite definitively in both their store product description and a Knowledge Base article, both of which have already been posted to the thread multiple times.

http://store.apple.com/uk/product/MD836B/A/apple-12w-usb-power-adapter?fnode=3c

http://support.apple.com/kb/HT4060 (See the table at the bottom).

(My apologies to anyone visually impaired)

This is a very large but also instructive thread about a common misconception.

I think Mr. Finch is totally right. And I would like to add that his explanation also answers the question whether you can use a MacBook Pro Retina power unit (85W) to charge a MacBook Air (which comes with a 45W power unit). Turns out you can, without having to fear anything...

Apple officially states: (http://support.apple.com/kb/HT2346)

<< QUOTE BEGINS >>>

For instance If you have a MacBook (13-inch Late 2009) that normally uses a 60W adapter, you can also use an 85W adapter with that computer. You would not use a 45W adapter with that computer; it would not provide enough power for that MacBook.

Using an adapter of higher wattage than the adapter that came with the computer will not cause the computer to charge more quickly or otherwise operate any differently than using the adapter that came with the computer. The tables further down in this article show the style of connector that initially shipped with each model of MacBook, MacBook Pro, and MacBook Air.

<< QUOTE ENDS >>>

Note that Apple doesn't call the power unit a charger, because as Mr. Finch pointed out long ago, the charging circuit is in the iPhone or iPad or whatever... What we colloquially call a "charger" is in fact just a power unit.

What this conversation diverted to is highly educated people using there qualifications to measure in on the fairly insignificant subject.

I'm sorry I wasn't commenting necessarily on significance that has already been compared quite sufficiently. I was making the accurate statement that the engineers obviously didn't want to accept. The mathmatical equation they tried to shoot down and the reasons they might do this. Engineering is all about mathmatices (laws of physics) especially since they were commenting on it themselves. The question is, how much shorter life does the battery have? Is Merlin 1128 satisfied that the difference in battery life is "SIGNIFICANT" to HIM or not. That's for him to answer. But when engineers get to commenting on the specifics (ignoring mathmatical equations that their education is based on) I feel it necessary to point out their flaw. Why would they ignore their own education.

By the way, the mathmatical equation you don't care about was demonstrated in kelvinnguyen's comment back in April on the 11th.

Re: Can use ipad charger to charge iphone?

Apr 11, 2013 2:11 AM (in response to emfung)

Very simple.

1Ah = 3600 C (coulomb)

1 mAh = 3.6 C

Your iPhone needs total charge Q = 1440 mAh = 5184 coulombs

Your iPhone has a fixed battery inside. So capacitance is constant. C is constant.

C = charge/voltage = Q / V

V is constant (iPhone/iPad charger supplies 5V)

Q = charge_current x charge_time = I x t

So:

C = Q / V = (I x t) / V

=> charge_time t = ( C x V ) / I

in this equation we have C constant, V constant (5V).

Therefore, higher charge_current will reduce charge_time.

Your iPad charge gives 2.5 amps (compared to 1amp charger), it will charge your iPhone faster.

There is no other side effect from this equation. 🙂

You can go back to the original post to try and make the foregoing comments seem insignificant to the post, but that doesn't make the statements any more accurate that came from the ones that made them. And I don't think you know how much respect I have for such people, even Lawrence Finch, and FMaxwell. I'm sure I could learn a lot from them. I don't know how much I would learn from someone that just wants to make trivial their comments, saying the post was insignificant to scientific accuracy. Oh well, I'm sure you will do well without any further comments from me. I don't have time. BTW, I didn't know we were on the Last Word With Lawrence O'donnel show.

• Now it is confirmed* that It is 100% safe to use an iPad Charger (12W) or (10W) to charge an iPhone (5, 4S, 4 3GS, 3G, and 2G) and iPods (all versions).
• But there is no benefit or disadvantage on doing that b/c it wont charge your iPhone faster or damage your device battery
• Can be used as a replacment only.
• iPhone uses 1 amp current to charge the battery not more than that so there is no over heating issues
• iPad charger can provide higher power (up to 12W) if needed (iphone needs only one amp or 5W)
• I hope this clarifies things a little bit.

* I had a long discussion with a graduate student (Electrical and Material Science Engineerin with thesis on battery life)

I am an Electrical Engineer at an aerospace firm. I design charging algorithms and software for batteries that cost more than the average house.

The incredibly patient Lawrence Finch has consistently been correct throughout this discussion.

In summary:

1. If you believe that your iPhone's battery life was shortened by the use of an iPad AC adapter, you are wrong.
2. If you believe that your iPhone "feels warmer" when charging from an iPad charger, you are wrong.
3. The iPhone charging is regulated within the phone. You could attach it to a power supply capable of 5V at 500 amps and it would not charge any faster or be damaged by the experiment.
4. Your inability to resisting swilling down your entire 40oz. Super Big Gulp in one five minute sitting is not evidence that your iPhone is similarly unable to limit it's intake rate and quantity to what it needs.

I don't care if your sister's friend's brother claimed that his iPhone battery was destroyed by using an iPad charger. I don't care if ScooterBoy426 wrote that his iPhone melted because he used an iPad charger. Keep those stories to yourself and don't pollute this thread with vague, unscientific, anecdotal claims of shortened battery life or 'feeling warmer.'

I am neither as patient as Mr. Finch nor as nice (as you have no doubt noticed), so I will be direct: Unless you have expertise in electrical engineering, then limit yourself to asking questions in this thread and, if an electrical engineer answers your question, saying "thank you." That will go a long way towards increasing the signal-to-noise ratio in this thread.

Noahwhite2014 wrote:

according to my tests, My iPhones are ALL broken internally due to the variance in charging times.

Then your tests are invalid.

In a previous message I wrote: "The iPhone charging is regulated within the phone. You could attach it to a power supply capable of 5V at 500 amps and it would not charge any faster or be damaged by the experiment."

Your iPhone will not charge faster on an iPad power adapter (or any other 5V DC power source) than it does on its supplied power adapter. Lawrence Finch has said the same thing. Therefore, it is no longer a point for discussion; it is an established fact. So let's move on.

Since you don't want to read the entire thread, I will summarize:

• Use of the iPad power adapter to charge the iPhone is approved by Apple.
• Use of the iPad power adapter does no harm.
• Use of the iPad power adapter provides no benefits–other than convenience.
• The iPhone battery will not charge any faster using the iPad power adapter.
• The iPhone will limit its current draw to 1A maximum, even with an iPad adapter than can supply 2A or 2.1A.

Do you have any other questions related to the use of iPad power adapters to charge your iPhone?

emfung wrote:
Hi, I have both iPad and iPhone 4. Can I use iPad charger for iphone and vise versa?

By the way, why is my iPad not charging when connected to computer via USB?

Why does iPhone doesn't show battery percentage on the status bar?

stylinexpat wrote:
I also have an Ipad and an Iphone 4. Anyone else around here using the Ipad charger to charge the Iphone 4? Am wondering if this will harm the Iphone 4?

I mistakenly plugged my iPad charger into my iPhone last night and vice versa. this morning I lost 62% of my iPhones charge in 2 hours doing nothing other than answering a text message. once. clearly this IS harmful to the battery and I would recommend that no one charges their phone in this manner. alternatively I have lost 1% of the iPad charge while writing this response, so also not normal.