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Reiger

macrumors regular
Original poster
Jun 8, 2007
158
0
Netherlands
I'd like to use an iPad charger to charge my new iPhone 4. However, only if this won't damage the iPhone. I know that the iPad charger provides more power, so this will charge the battery faster. Is this harmful? Both chargers have the same USB connection.

I can't find any Apple Support page about this issue. Using Google I can only find people who want to use an iPhone charger to charge the iPad, which is ok but slow. Both the iPhone 4 and the iPad are not yet for sale in the Netherlands, so calling Apple didn't work.

I hope someone with the same issue, can help me :)
 

androidpopjr

macrumors newbie
Jun 22, 2010
20
0
On apples website it says the charger works with all ios items. I've done it since April, and nothing bad has happened to me.
 

3460169

Cancelled
Feb 18, 2009
1,293
212
The iPad charger has a higher output wattage (I think 10 watts) due to the iPad having hefty charging requirements. However it is perfectly fine to use the iPad charger with iPhone. If anything it'll likely charge the phone a bit faster.
 

jdong

macrumors member
Nov 24, 2008
33
0
Yes, it is! In fact it's safe to use the little iphone charger to charge the iPad too. If you take apart the charger, you'll notice there's a USB controller in there. The chip negotiates the maximum safe current with the device.
 

matt15f

macrumors member
Jun 16, 2010
44
0
I do it all the time, and it does seem to charge the iphone faster than the iphone charger.
 

Zimmy68

macrumors 68000
Jul 23, 2008
1,989
1,606
I just wish Apple would have made the iPhone 4 fit into the iPad dock, like the 3GS does.
 

sithbrach

macrumors newbie
Jun 18, 2011
2
0
Let's look at the relevant science.

Ohm's Law: http://en.m.wikipedia.org/wiki/Ohm's_Law

http://en.m.wikipedia.org/wiki/Volt


That tells us what the 5v x 1 or 2A translates to. It would indicate that twice the wattage is coming out of the iPad charger (W=V*A) and twice the current (I=V/R).

As I understand it, the block acts as a transformer: http://en.m.wikipedia.org/wiki/Transformer

So, it takes the 120V*15A=1800W power from the outlet and converts that power so that it will be transmitted at a much lower rate, giving the device less of that wattage.

I'm not sure if the earlier post by someone was trying to say that the iPhone has a particular resistor of it's own and so any different level and rate of power would simply dissipate, but wouldn't that still be stressful on that resistor?

I think, in the end, one would be better off spending the couple of bucks for an iPhone charger.

If there was absolutely no difference, then why would they make different chargers with different values? There would only be a need for stronger chargers for larger, more powerful devices, but the inverse (using that more powerful charger for a smaller, less powerful device) wouldn't make any sense.

Just use the corresponding charger.
 

mortenandersen

macrumors 6502
Apr 9, 2011
412
20
Norway
Back to the first question, please!

Ohm's Law: http://en.m.wikipedia.org/wiki/Ohm's_Law

http://en.m.wikipedia.org/wiki/Volt


That tells us what the 5v x 1 or 2A translates to. It would indicate that twice the wattage is coming out of the iPad charger (W=V*A) and twice the current (I=V/R).

As I understand it, the block acts as a transformer: http://en.m.wikipedia.org/wiki/Transformer

So, it takes the 120V*15A=1800W power from the outlet and converts that power so that it will be transmitted at a much lower rate, giving the device less of that wattage.

I'm not sure if the earlier post by someone was trying to say that the iPhone has a particular resistor of it's own and so any different level and rate of power would simply dissipate, but wouldn't that still be stressful on that resistor?

I think, in the end, one would be better off spending the couple of bucks for an iPhone charger.

If there was absolutely no difference, then why would they make different chargers with different values? There would only be a need for stronger chargers for larger, more powerful devices, but the inverse (using that more powerful charger for a smaller, less powerful device) wouldn't make any sense.

Just use the corresponding charger.

Back to the first question again, please: Is it safe to use an iPad charger to charge the iPhone 4?

This last post above is confusing in the light of all the contrary experience from the other posts.
 
Last edited:

Gav2k

macrumors G3
Jul 24, 2009
9,216
1,608
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5)

Yes it is safe. If u buy an iPad charger from apple the box states it's for the iPad iPod and iPhone.
 

Blinny83

macrumors member
Feb 10, 2011
86
1
Seems like my iPhone charges a bit faster with the 10 watt iPad charger. The reason for different chargers is obvious if you've ever tried to charge an iPad with an iPhone charger or a USB port though.
 

OllyW

Moderator
Staff member
Oct 11, 2005
17,196
6,799
The Black Country, England
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5)

Yes it is safe. If u buy an iPad charger from apple the box states it's for the iPad iPod and iPhone.

It also tells you the same thing on the Apple Store.

It even has a nice picture just to make sure. :D

Screen shot 2011-06-19 at 14.14.14.png
 

ghostlyorb

macrumors 6502a
Jan 9, 2010
920
0
Virginia, USA
I'd like to use an iPad charger to charge my new iPhone 4. However, only if this won't damage the iPhone. I know that the iPad charger provides more power, so this will charge the battery faster. Is this harmful? Both chargers have the same USB connection.

I can't find any Apple Support page about this issue. Using Google I can only find people who want to use an iPhone charger to charge the iPad, which is ok but slow. Both the iPhone 4 and the iPad are not yet for sale in the Netherlands, so calling Apple didn't work.

I hope someone with the same issue, can help me :)

I was skeptical at first.. because of some bad reviews I read. But one day I had no other charger except my iPad charger. It works. Charges just as fast.. or faster (I'm not sure). Using it right now, actually. haha.
 
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