Can use ipad charger to charge iphone?

Your analysis does not contribute any useful information. APPLE states that the 2.1 amp charger is compatible with the iPhone. Unless you are into conspiracy theories and believe that Apple says this so they can sell more batteries, that should be sufficient.

As an engineer you know (I hope) that the current supply capability of a power source only limits the maximum current that can be drawn from the source. Each device connected to the source only draws what it needs. That's why you can have a 200 amp panel for your incoming power, but not instantly blow all of the lightbulbs in the house.

You may have also missed the post that links to a video of someone actually measuring the power consumed by an iPhone being charged. As an engineer I hope you believe in actually measuring, and not just hypothesizing. The video shows that the iPhone consumes 5 watts when connected to a 1 amp (5 watt) iPhone charger, and also consumes 5 watts when connected to 2.1 amp (10.5 watt) and 12 watt iPad chargers. Here's a link to the video: http://www.youtube.com/watch?v=DC4gPxc89Wg

I also did my own measurements, although not as precise. I charged my iPhone from a known state of charge (20%) to 100% using the iPhone charger. During the high current charge cycle I measured the temperature of the phone with a laser thermometer after 30 miutes. I repeated the test using the 10 watt charger. The charge times were the same, to within a few minutes, and the temperatures were likewise.

Ahh, nearly forgot to mention that I have been charging my iPhone 4S with a 10 watt Apple power source for the past 18 months, with no issues.

I reviewed this thread, Lawrence, to make a decision about a car charger, dual 2A ports or one with 2A and 1A. I admit that I did not find the Youtube video and I agree that is seems the internal charging circuit does limit wattage.

Still a slow charge from a USB cable connected to a PC, every so oftern is likely to extend the life of the battery.

So in the end, I saved $10 and I can only recharge 1 iPad at a time in my vehicle. The world did not come to an end. I understand Ohm's law, but not everyone does. The purposes of discussions like this is to help one another find information that may not be readily available.

Thank you for the YouTube link, but you hostility is not needed, nor is it intimidating. Try being helpful, not a know-it-all.

Hi ActionJunky,

I would suggest that you post your findings in a separate thread with the specific titling that your response refers to. This thread is about charging a phone with an iPad charger.

Since your post is specifically addressing your findings concerning car chargers, and you hope it that they will help someone looking that kind of information, I can promise you, they won't find it buried here. Nor would they even look here to see if that kind of information was contained somewhere in this rat's nest of nattering negativity, misinformation, indignity, and refusal to acknowledge actual results which, in some cases, go all the way back to January of 2010....

So, since you put in the effort, why not make it useful to others who may be looking for just that information!

Cheers,

GB

Wow, curious I am about the original question. Then reading on about engineers, degrees or PHD's, whatever... I was sucked in to who's right or wrong and how they can prove it. The way some of you elaborate on, or justify why and how your correct as to the function of the two chargers in question is interesting. Honestly, I only read about half the thread, that's all I could handle. I just want to share my personal experience with the 5w charger vs the 10w charger on my old iPhone 4. Clearly the 10w charger does charge faster and generates some noticeable heat. The 5w charger does its job, taking longer. I charge my phone every night on a 5w charger, by noon the battery is down to 50% or less, by the time I get home from work, the phone is almost dead. This is when I reach for my 10w charger, knowing it will charge fast. From my personal experience, I think the 10w charger has shortened my batteries lifespan. The phone is over 2 years old and should be replaced anyway. Currently I now have a charger in nearly every room of my house. Personally I am waiting for the next phone to be released in a few months, once I have that, I'm going to stick with just the 5w charger. The iPad mini came with a 5w charger (not a 10w), the 10w is old, dated, discontinued, and bad for an iPhone. (My opinion).

I live on the west coast in the Silicon Valley (where Apple was founded), and I'm just a measly electrical contractor. All the formulas your rattling off about current, demand, resistance, Ohm's law - whatever, is interesting to hear from your doctorate or engineering perspective. The fact is, nobody cares. There was initially a simple question that needed a simple answer.

Apple wants us to continue emptying out our pockets for the next device, these things aren't designed to last for decades. Use whatever charger suits your needs, slow, fast, 10w, 5w, warm, not so warm. Who cares? Use it up to its full capability then throw it away and go buy a new one. That's what I do.

The 3ph 240v questions what's his name was asking about - I'd be happy to answer, and have questions for him. Otherwise, hope sharing my experience helped someone somewhere.

Cheers

Wow, curious I am about the original question. Then reading on about engineers, degrees or PHD's, whatever... I was sucked in to who's right or wrong and how they can prove it. The way some of you elaborate on, or justify why and how your correct as to the function of the two chargers in question is interesting. Honestly, I only read about half the thread, that's all I could handle. I just want to share my personal experience with the 5w charger vs the 10w charger on my old iPhone 4. Clearly the 10w charger does charge faster and generates some noticeable heat. The 5w charger does its job, taking longer. I charge my phone every night on a 5w charger, by noon the battery is down to 50% or less, by the time I get home from work, the phone is almost dead. This is when I reach for my 10w charger, knowing it will charge fast. From my personal experience, I think the 10w charger has shortened my batteries lifespan. The phone is over 2 years old and should be replaced anyway. Currently I now have a charger in nearly every room of my house. Personally I am waiting for the next phone to be released in a few months, once I have that, I'm going to stick with just the 5w charger. The iPad mini came with a 5w charger (not a 10w), the 10w is old, dated, discontinued, and bad for an iPhone. (My opinion).

I live on the west coast in the Silicon Valley (where Apple was founded), and I'm just a measly electrical contractor. All the formulas your rattling off about current, demand, resistance, Ohm's law - whatever, is interesting to hear from your doctorate or engineering perspective. The fact is, nobody cares. There was initially a simple question that needed a simple answer.

Apple wants us to continue emptying out our pockets for the next device, these things aren't designed to last for decades. Use whatever charger suits your needs, slow, fast, 10w, 5w, warm, not so warm. Who cares? Use it up to its full capability then throw it away and go buy a new one. That's what I do.

The 3ph 240v questions what's his name was asking about - I'd be happy to answer, and have questions for him. Otherwise, hope sharing my experience helped someone somewhere.

Cheers

Thanks for that link, but I'm certain that there will still be people who won't believe it and who will believe it is a scam by Apple to shorten the life of iPhones so you have to buy a replacement.

The same information in different forms has been posted many times in this thread, along with actual measurements (including one on video) showing that the iPhone draws the same amount of power from a 5 watt and 12 watt adapter. Yet there are still people who claim that the 12 watt charger charges the phone faster. How can it possibly do that if the input power is the same for both adapters (as clearly demonstrated in the video?)

I've linked to the video yet again: http://www.youtube.com/watch?v=DC4gPxc89Wg

Well, as I said somewhere around a billion posts ago.....I've been charging my iPhone 4 with my iPad charger for the last 5 years and 10 months, and the battery is still going strong.

That is impressive. Especially as the iPad has only been released for just over three years.

If anyone is interested in anymore anecdotal evidence, I've been using an iPad charger on an iPhone 4 and 4S for the last couple of years without any obvious detriment. Interestingly, my company BlackBerry Bold 9900 will only charge from a 1A plug, and refuses anything stronger (I can only assume it has a more fussy power management IC than Apple devices).

Just seeing if anyone was paying attention....😁

You will notice that you are the first one to actually catch it! No, actually, it was a typo....meant to put a 2 in there instead of a 5....

On my numeric keypad, the 5 is right above the 2....

Thanks for pointing that out!

Cheers,

GB

Dear Lawrence, I have an iPad third-generation, and an iPhone 5. In searching for a couple of extra chargers for my iPad, I ran into this query about amps and voltage to charge both my iPhone and my iPad. I purchased my iPad on eBay and it came with the little cube that is typically used for iPhones. I had no idea that there was a difference in voltage on either device. I did notice when I charge up my iPad with the iPhone charger, it takes a day and a half to get a full 100% charge. I only stumbled upon the knowledge that there was a difference in voltage, because the generic wall chargers that I was looking at often stated that they would not support an iPad. Having read this several times from different vendors on eBay, I decided to Google that information and lo and behold, being just a uninformed woman, I realized that the iPad needed a stronger voltage charger. Who would've thought? But it made sense, because the iPad is so much larger than an iPhone, so my common sense kicked in. I ultimately found a dual charger in that one side supports an iPhone charge, and the other port supports an iPad charge. So I purchased it and when it came, I connected both units up and to my surprise and delight, the iPad charged so much faster than it originally had, when I had used the little cube. But I have noticed here on this forum, that your opinion is being challenged by another person who is knowledgable about electrical engineering, and that it doesn't matter that if you charge your iPhone on an iPad charger, it will not make a difference on the iPhone battery. Well my common sense tells me not to do that, because I have noticed the difference in the speed at which the iPad charges on the higher amp plug. It's kind of like putting regular octane gas in a car that requires high-octane gas. That car is going to knock like crazy because it's not running to capacity, and eventually, that 'damage' will ultimately cause permanent knocking within the motor, hence, lowering maximum engine output, but it won't completely ruin the motor. So why would anybody challenge a lower voltage iPhone with that higher voltage plug-in for an iPad that's just going to wear out your battery faster, not to mention what it might do to the device itself after repeated overuse?

Sadly, after over 200 replies of various levels of lack of knowledge, I did not bother to read the wodge of non-paragraphed response that you have posted. Just too much on a Friday evening. Perhaps you could repost bullet points?

I don't believe that you are still discussing this trivial matter for almost a year!

The answer to this question is very simple.

If the charging time using an ipad charger is shorter than the time you charge with an iPhone charger then the iPhone battery will short live!!

And I still didn't make that test... so I can't tell for sure...but if somebody will test it, or if I'll find the time to test it, it would be nice to post the answer and finally end that saga!

omega66 wrote:

I don't believe that you are still discussing this trivial matter for almost a year!

The answer to this question is very simple.

If the charging time using an ipad charger is shorter than the time you charge with an iPhone charger then the iPhone battery will short live!!

Totally, completely wrong. You don't have a clue. And you haven't read the thread. As long as the charge rate is within the ratings of the battery fast charging will not shorten the life of a battery. But this is irrelevant, because the iPad charger does NOT charge the battery faster than the iPhone charger. I HAVE done tests with both, and also measured the temperature of the phone during charging with both. The charge time is about the same, and the temperature as MEASURED (not "it feels warmer") is about the same.

And I still didn't make that test... so I can't tell for sure...but if somebody will test it, or if I'll find the time to test it, it would be nice to post the answer and finally end that saga!

People have made the test, many times, and reported the results. The answer is that the iPhone battery can be charged with either the iPad charger or the iPhone charger. It makes no difference. As the video shows, the power going into the charger is exactly the same with either charger. If the power going in is the same with either charger it is impossible, unless the laws of physics are violated, for an iPad charger to charge the phone faster than an iPhone charger will charge it.

Lawrence Finch wrote:

.

And his silence is worth a thousand words.... 🙂

If only we mere mortals could kill this ridiculously long thread! Never have there been such rantings from such a lacking of basic electronic knowledge.

Didn't take long to prove my theory why this thread hasn't been killed!

1. This is a user-to-user tech support site and Apple doesn't officially post in this forum! You would know that if you bothered to read the Terms of Use you agreed to when you joined.

2. Apple has already unequivocally stated on their web site that the iPad charger can be used on iPhones. How clearer can that get! You would know that if you bothered to read this thread before posting.

I posted a while back that I had issues keeping the iphone 5 charged. I have since found my iPad 2 charger and use it on occasion for faster charges. I had planned to record charging times when I posted last but like everyone else it just never really happened. My % is at 5 and I'm about to charge it from 1% to full with the iPad charger with my new iphone 5 my wife got with the provided iphone charger.

I have to mention that since I've been using the iPad charger my phone dies so fast. I can't go half a day unless I have wifi off.. Lte off brightness on low etc without it dropping to below 10/20%. Its horribad. At 2% now.. About to plug in ... Will take photos !!