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Can use ipad charger to charge iphone?

498723 Views 342 Replies Latest reply: Sep 10, 2013 3:00 PM by ronhenderson2 RSS Branched to a new discussion.
  • deggie Level 8 Level 8 (44,930 points)
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    Nov 7, 2012 3:17 PM (in response to Knert88)

    I charged my iPhone 4 almost exclusively with my iPad charger. Never got overly hot, never killed the iPhone. But you are saying we should believe your girlfriend's experience (1 instance which may no have been related to the charger) over Apple's engineers recommendations?

  • Knert88 Calculating status...
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    Nov 7, 2012 3:46 PM (in response to deggie)

    deggie wrote:

     

    I charged my iPhone 4 almost exclusively with my iPad charger. Never got overly hot, never killed the iPhone. But you are saying we should believe your girlfriend's experience (1 instance which may no have been related to the charger) over Apple's engineers recommendations?

     

    As long as it not getting hot while charging, it's no problem. And I did say it might kill your iPhone battery.

    My girlfriends phone was just an example, my iPhone 5 gets much hotter when charging from 10-20% to 80%(Fast charge stage) with the 10W charger. But with the 5W charger it's "hot", but nowhere near the temperatures when using the 10W.

    My brother charged his iPhone 5 with the 10W for a while, claiming he got better battery life with it, but it got worryingly hotter after every cycle, so he switched to his 5W.

     

    Where does Apple recommend using the iPad charger for iPhone? It's compatible, yes. But that does not mean optimal or recommended.

     

    But by all means, use the 10W to charge the iPhone, it's your phone

  • deggie Level 8 Level 8 (44,930 points)
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    Nov 7, 2012 3:48 PM (in response to Knert88)

    I seriously doubt that Apple's lawyers would allow them to list the charger as compatible if it was possibly going to damage the device in question or it was not recommended. I'll continue to listen to Apple instead of you.

  • Lawrence Finch Level 7 Level 7 (24,600 points)
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    Nov 7, 2012 4:00 PM (in response to Knert88)

    You are clueless. It's not even worth answering. And all of your "points" have already been addressed in this thread. Try reading it.

     

    Think about your house for a minute. The electric service is probably 200 amps. The voltage coming in is 220 volts. So the total power coming into your house is 200 x 220 or 44,000 watts. So why don't all of your 60 watt lightbulbs explode instantly? This is what you are saying when you say a 10 watt power source cannot safely power a phone that requires 5 watts.

  • soldit2u Level 1 Level 1 (0 points)
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    Nov 7, 2012 4:19 PM (in response to Lawrence Finch)

    It's not even worth answering.

     

    all evidence to the contrary...!

     

    Knert88 - you're wasting your time mate - although I'm sure you are experiencing these issue (as I did) Unless Lawrence sees it himself - it's mumbo jumbo - black magic.

     

    I had my last post removed by him complaining and others complaining.

     

    I have several Apple products, I love them - Sadly, I don't have a degree in electrical engineering, which means I can't feel heat from the phone and I  also can't SEE the battery meter either

  • Knert88 Level 1 Level 1 (0 points)
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    Nov 7, 2012 5:10 PM (in response to Lawrence Finch)

    Lawrence Finch wrote:

     

    You are clueless. It's not even worth answering. And all of your "points" have already been addressed in this thread. Try reading it.

     

    Think about your house for a minute. The electric service is probably 200 amps. The voltage coming in is 220 volts. So the total power coming into your house is 200 x 220 or 44,000 watts. So why don't all of your 60 watt lightbulbs explode instantly? This is what you are saying when you say a 10 watt power source cannot safely power a phone that requires 5 watts.

    Hehe, 200A on the main fuse (or 200A breaker in the US) in a house seems a bit high, <63A is normal depending on the electrical system classification. A bit unrealistic example from a senior-engineer... Btw, be careful saying I'm clueless, that is a bit nonchalant as you don't know my level of education.

     

    I know how a standard lithium-ion polymer battery charger IC works, I've made several of them in lab-classes.

    And a regular ALC IC(Advanced Linear Charger IC) regulates the current by this formula: Ireg=Vreg/R1, let's say R1=4.5Ohm

    This makes the IC more sensitive to DC-Source voltage dip, and a lower voltage dip makes a higher charge current.

    My guess is that the 5W DC-supply(charger), has a bigger voltage dip than the 10W.

     

    Examples:

    5W delivers 4.5VDC at charge - this makes the charge current 1A

    10W delivers 5VDC at charge - this makes the charge current 1.11A

     

    Not much difference, but it might be enough to make a lot of extra heat.

    And not to mention the IC power/heat dissipation, which of course increases in "overload" situations.

     

    This is just my thoughts around the charger issue, and I might be wrong, but it doesen't make my(and many other) iPhone's colder when I use the iPad charger.

    And of course, this does not happend to every iPhone out there, but the problem definitly exists, even with brand new phones.

     

    So please Mr. Finch, could you explain the reason why many iPhones get hot when using the iPad charger?

  • Lawrence Finch Level 7 Level 7 (24,600 points)
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    Nov 7, 2012 5:24 PM (in response to Knert88)

    Most new houses in the US have 200 amp service; my older house (220 years old) only has 150 amp service, which is only 33,000 watts. Same issue, howeve.

     

    My iPhone gets hot with the iPhone charger. It doesn't get any hotter with a 10 watt charger (3rd party, not Apple's). And I've been using a 10 watt charger most of the time for 3 phones over 5 years, with no obvious detrimental effects. I don't know why you think a 5W charger delivers 4.5 VDC; mine measures at 5 volts. And it doesn't matter, because the charger is in the phone, not in the thing you plug into the wall. The thing that plugs in the wall is a 5 VDC power source (actually, by the USB spec, 4.5 to 5.5 V), not a charger. You could use a 1,000 watt 5V charger and it wouldn't make any difference.

     

    But the best argument is deggie's - If the iPad charger could damage an iPhone Apple's lawyers would never have let the web site list the iPhone as being compatible with it.

  • Knert88 Level 1 Level 1 (0 points)
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    Nov 7, 2012 6:15 PM (in response to Lawrence Finch)

    Lawrence Finch wrote:

     

    Most new houses in the US have 200 amp service; my older house (220 years old) only has 150 amp service, which is only 33,000 watts. Same issue, howeve.

     

    My iPhone gets hot with the iPhone charger. It doesn't get any hotter with a 10 watt charger (3rd party, not Apple's). And I've been using a 10 watt charger most of the time for 3 phones over 5 years, with no obvious detrimental effects. I don't know why you think a 5W charger delivers 4.5 VDC; mine measures at 5 volts. And it doesn't matter, because the charger is in the phone, not in the thing you plug into the wall. The thing that plugs in the wall is a 5 VDC power source (actually, by the USB spec, 4.5 to 5.5 V), not a charger. You could use a 1,000 watt 5V charger and it wouldn't make any difference.

     

    But the best argument is deggie's - If the iPad charger could damage an iPhone Apple's lawyers would never have let the web site list the iPhone as being compatible with it.

    I'm not going to argue about the US house electrical specifications, as a live in Europe, but you have 110V?

    Which requires twice the amp as 220V for the same amount of wattage.. Really of topic, but I had to ask.

     

    I know this doesen't apply to all iPhones, but many of them get really hot when using the iPad charger, this is a fact I know. The reason however, is unknown, and there may be several causes that generates this symptom.

     

    Let me explain you about the "chargers"; they are switchmode powersupplys with PSFC(Power Supply Feedback Circuit), which make super smooth 5VDC at zero load. But super smooth voltage in this context, means "ripple-smooth", not 5VDC at any load. I'm pretty sure you didn't measure the output of the supply when charging you phone, because the voltage is most likely to drop.

    The reason I used 4.5VDC in my example, is because that is the low-voltage threshold of a regular ALC IC, and if the charger should cut the voltage off or it squeezes itself to the maximum. And since the 5W charger is compatible with the iPad, I assume it has a very low threshold, making the charge-voltage close to battery idle-voltage at iPad charge.

     

    First of all, saying something is compatible with something, is a lawyers statement. It's not the most precise statement, and it definitly has some gray areas regarding the technical aspect. Saying something is compatible, means it's capable of something. Is the 10W charger capable of charging a iPhone? Sure! But it's not necessary the ideal charger... Hmm, of course we expect it to be the ideal charger, since it's Apple, but how do we really know?

     

    Second of all, the iPad charger still makes many iPhones really hot, regardless of what Apple says.. There is just too many people experiencing these symptoms. I'm not saying all this just to argue, this is a real problem among many iPhone owners.

  • Joshmcz06 Calculating status...
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    Nov 8, 2012 2:15 PM (in response to merlin1128)

    EVERYONE!!  I am not trying to argue with anyone but I just want you all to know that MERLIN1128 is correct.  I just dealt with this personally on 2 iphone and the battery life started to die at 5%, then 10%, then 20%. 

     

    So please trust me, this WILL SHORTEN YOUR BATTERY LIFE!  However, apple will replace your phone for free if you tell them the battery is not working correctly no questions asked

    Hope I helped some people out there :)

  • thatdrh Calculating status...
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    Nov 9, 2012 5:07 PM (in response to Lawrence Finch)

    Good thing you only chimmed in...  In a febble attempt to prove that guy wrong...    Now... perhaps that iphone charger is a simple transformer and not a regulated power supply Which many chargers are unregulated, it forcefully applies the charge. In the case of new electronics with self contained batteries, it internal inturrupts the charging circuit from the internal battery..

     

     

    SO in the event that its unregulated and the device has no way to switch off the incoming current, then yes, it will burn up stuff like he stated! The extra unused engergy gets turned into heat..   The primary in the transformer only knows whats its being asked of by the secondary ... So it will put out what its windings are capable of.. So if it could put out 5 watts, then 5 watts is what its putting out and nothing less. That is where the regulation circuit comes into play. 

     

    Hair dryers you used for example are simple devices that pull as much as they can (designed to; based on their winding (or elements).  Televisions have transformers and those are ususally regulated inside.    

     

    SO that dude you're attempting to totally discredit... Well its a bit rude.  He is correct if the charger is unregulated.

  • Lawrence Finch Level 7 Level 7 (24,600 points)
    Currently Being Moderated
    Nov 9, 2012 5:12 PM (in response to thatdrh)

    I suggest reading the other messages. It isn't a charger. It is a 5 volt USB power supply that meets USB specs. The charger is in the phone.

  • modular747 Level 6 Level 6 (15,795 points)
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    Nov 9, 2012 6:38 PM (in response to thatdrh)

    ALL regulation is done IN THE PHONE. Charging rate is determined ENTIRELY BY THE CHARGING CURCUIT IN THE PHONE.  The iPad charger differs only in that greater current can be drawn by the iPad charger as needed. The iPhone charger in the phone  can't use this extra current capacity.

     

    There's no way the iPad charger can charge the phone battery too rapidly or overcharge unless it's grossly defective, in which case it would fry the charging cur hit entirely.

  • Lumens Calculating status...
    Currently Being Moderated
    Nov 11, 2012 9:32 AM (in response to modular747)

    This was exactly my thoughts on the matter, until I read elsewhere that different chargers can have different voltages set on their data lines. This enables attached compatible devices to know what power supply is attached, and its maximum current capability. This in theory could mean that the iPad charger (should I say power supply) would enable the phone to charge at a higher rate.

     

    I didn't have much equipment to hand and didn't have a spare USB connector to hack apart and measure the DC current draw from the chargers. So I measured the AC current draw from the chargers when connected to an iPhone 5. Within 0.2mA both read the same.

     

    iPhone 5 connected to an iPad charger (supplied with 4th Gen iPad) 22.2mA AC when first connected, dropping to 19.2mA when the display turned off. Checked after 10mins with battery at 50% and still reading the same.

     

    When connected to the iPhone charger, as I said above, the readings were within 0.2mA.

     

    This is obviously a very quick and crude test, and I haven't monitored the whole charging cycle but I'm happy to now use either charger for my phone. The resulting DC charging current (using 240V RMS and ignoring the small power supply inefficiency) is 922mA DC, which is well within a 1C charging rate.

  • itsgitty Calculating status...
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    Nov 17, 2012 1:25 PM (in response to emfung)

    Hey guys, it looks like the consensus is that the iphone regulates the charge and it doesnt matter if the charger can provide more power or not. I believe this but at the same time I am confused.

     

    When I use the iPad charger with my iPhone, my phone charges significantly faster and gets hotter as well. How can this be explained? If the iPad charger doesn't allow more current/power through than the iPhone will allow, which should be the power that the iPhone charger gives, how does the iPhone definitely charge more quickly and get hotter?

  • soldit2u Level 1 Level 1 (0 points)
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    Nov 17, 2012 1:35 PM (in response to itsgitty)

    When I use the iPad charger with my iPhone, my phone charges significantly faster and gets hotter as well.

     

    Hallelujah!

     

    That's all I've been saying from the start

     

    Plus, my charge depletes much quicker when charged with the iPad charger - what about yours?

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