Can use ipad charger to charge iphone?

It was suggested to me that I read this entire thread, which I have finally accomplished, after 3-4 evenings spending at least 1-2 hours per evening on reading this. All in all, I am glad I read this and want to thank the individual who suggested I read this whole "darn" thing. :-)

I have learned a lot and would like to thank pretty much all of the contributors.

Especially the individuals who have the highest qualifications and who have made EE and computer science their careers. I am very glad, though puzzled admittedly as to how much of their own time, expertise and the efforts that these people give donating so much to helping others and their perseverance in threads, especially one like this one!

So I watched the Utube video. That was that I thought. Extremely clear, tested and measured using the scientific approach, etc. I then remembered that I have my own Kill a Watt device and can really quickly check the videos accuracy.. So assuming my Kill a watt is still functioning well, and it is not an old one,

I got some strange readings using it and was wondering if anyone could help clarify them.

As follows)

1) with my 10 watt 5 volt Apple power source connected to KAW (Kill a Watt) and the apple supplied 30 pin cord plugged into my IPad 2 while it was on, the wattage reading was 10.1 watts, some fluctuation to 10.2 watts. This was good and helped to possibly confirm the KAW is working.

2) I unplugged the 30 pin cord from IPad 2 and plugged it into my apple 4 iPhone. Readings I got where 5.8 watts when phone was turned on, 5.5 watts with phone off.

3) plugged my IPhone 4S into the 10 watt source next. Rather new phone. It read 6.5 watts power draw on the KAW while turned on and 6.2 watts when I put it to sleep.

So being confused a bit, I thought of switching power sources. I switched out the 10 watt to my 5 watt apple cube.

1) IPad draw was 6 watts

2) IPhone 4 was the same as it was with the 10 watt source which was 5.8 watts while turned on.

3) my new IPhone 4S still read at the same wattage level of 6.5 watts power draw while on the 5watt cube. as it also read on the 10 watt source. Asleep it dropped to 6.3 watts.

I don't understand yet how the readings all match up to themselves on 2 different wattage Apple Dc power sources which would be perfect except for how does the 4s pull 6.5 watts from both a ten watt and a five watt source.

My apologies if this was too long a post. I also umm... Am one of "those" people who used my IPad charger on my first iPhone 4 and also noticed severe loss of capacity after doing it for a while.

But I suspect that this may have to do with the very poor quality of my grid supplied utility electric power coming in through ancient wires, in a 100 year old building, in a rather rough neighborhood which gets browned out first whenever there are power shortages.

Actually I wonder if some of these other posts about IPad power source adapters burning out their I phone batteries may be experiencing lower quality "grid" supply as well. I have read 3-4 different articles, 3 of them on Wiki, all stating that the power supply on a lot of the grids, especially here on the northeastern sector, has overall very low quality of power.

Because of extreme old age, and an incredibly larger energy demand then when the systems were first built for a smaller population with a lot less air conditioners. same grid which also did fail completely that summer some years back.

Also i read that around my area, when the sinusoidal wave forms coming in on our grid , when they are measured, are not pure sine wave forms anymore, like those that one sees on newer grids further out west.

I guess this is several questions rolled into one long post. I would like some advice as to my readings and what about

The idea that Quality of received mains electric power may be what's affecting some of the internal charging circuitry over time when exposed i phones are being powered using above mentioned quality of power received? Thank you everyone. Cheers!

I did probe though that regardless of which power source I used, the phones did not draw more power from the 10 watt one then they did from the 5 watt one. And that is what this thread's focus sometimes meanders back to. :-)

1. The wattage you measured is what the power sources are drawing from the AC outlet. The ratings 5 or 10 watts are what ite can DELIVER to what's connected to them. To measure that you would have to connect a meter BETWEEN the power source and the phone. The delivered power is always less than what is drawn from the AC.

2. The local voltage can have an effect on charging , but minimal since the phone has a regulated charging circuit

3. The non-sinusoidal wave form may make the device buzz, but won't have any practical effect on charging. To do so, it would have to be so grossly distorted that most electronics attached to the grid would destruct.

From one engineer to another: thank you. Seeing someone offer this explanation while simultaneously interchanging Wh and W was making my head hurt.

Simple lesson kids: in this situation, concerning I = E/R, E is the only variable, and all USB chargers are likely regulated to 5VDC output as long as the input falls somewhere between 10-15VDC.

Furthermore, most devices containing lithium battery chemistry have additional charging circuitry built into the device, so even if you tried to feed it with a higher rail voltage, the phone's internal charger control should regulated to the necessary float level for the battery.

Quick tip: if you ever lose a charger, just go to a hotel front desk and tell them you lost one. They almost always have a big box of orphaned charges that you can dig through. Been doing this for 15 years...and have donated a few to the orphanage as well. Works 90% of the time, and if they say no, just go to the hotel next door....

Lots of great info here I wanted to say thank you to those who keep their calm and post in a respectful manner. My situation may be a little different but I thought I'd share anyways.

At work I use my iphone 5 to tether to my laptop which I use all day to browse online, occasionally stream soccer or hockey or basketball games etc. now this is sort of a rant I guess but I'm very frustrated with my iphone 5 at work. Its not the phones fault but I am in a very low metal clad building so the signal isn't the best. I am usually at 1-3 bars 3G unplugged. As soon as I plug in the phone it drops 1-2 bars hovering between edge and 3G. Now that's just me whining that my iPhone 3GS , 4 and 4s never had that signal drop plugged in but it is what it is I guess I just wanted to explain my situation leading up to today (which relates to the thread a bit).

So my routine for the day goes..

1. Get to work. Power off and plug in the phone for first 2 hrs.

2. At break turn on my phone and unplug it so I get best signal possible.

3. Watch battery sink like an anchor. During a 20 minute brea I can watch it go from 100 to about 70%.

4. Plug back in.. Power off or airplane mode. Hope for as much charge as possible. Or if I'm still connected ill deal with the disconnects and lag and plug the iphone in while tethering. If being used while tethering my battery will hold or slightly drop in % plugged in.

5.. Repeat every break etc until later in the day I'm at <5% where I have to stop tethering and power off and charge.

SO end rant about my battery usage and drain issues lol but today I thought maybe I would go out and buy a iPad charger and I did. I've learned that perhaps it won't do anything but kill my battery but I believe there is sufficient evidence to support that nothing will happen. I had hoped that maybe the iPad 10w charger I bought would allow more faster charging to be able to keep my battery up while being used but ill find out Monday.

After absorbing a lot of info on how the charging works .. I'd tethering is a big drain would it make sense to wish that with a 10w charger my phone will at least remain at its charge level while being used or actually charge during use due to the extra juice available ? I hope that even makes sense :o

I think it's matter of designed battery "charge rate" rate vs "charge capacity" and designed battery heat dissipation.

I can only assume an iPhone charge circuit has two modes. Allow full charge capacity i.e., trust the max charger amp output of 1 amp from 0 to 90% charge then switch to trickle mode from 90 to 100%. I observed these two modes from a downloaded iPhone charging application.

Given the above, charging at a max of 1 amp from an iPhone charger will not exceed the charge amp threshold of the battery for designed heat dissipation and other unknown factors that may influence battery life.

Should twice the flow be allowed by the charge circuit in the iPhone, the charge gates are wide open i.e., the charge circuit design assumes 1 amp max output but still accept a two amp flow, may induce extra heat in the battery thereby negatively impacting battery lifespan.

The charge circuit may prevent overcharge, but may not regulate the charge rate.

Keep in mind that yes, heat = work = watts. But we are dealing with constant input volts. Therefore, max amp flow is the variable here. I would think that voltage drop across a given battery type and battery resistance plays a role here as we'll, but these specs are unknown to me.

AYRONSENNA,

That sounds really good, I think that the 10W charger (if you bought it at an Apple Store, it might be a 12W because Apple 'updated' it to charge better the new iPads).

Anyways, I am really looking forward to see how your iPhone 5 does while tethering and charging with the 10W charger. This is my guess: It will definitely charge the battery (I mean, it will increase your battery charge level) while tethering, however, the iPhone might get hotter than when you plugged it with the 5W charger.

Will keep an eye on this thread by Monday evening!

You could connect a 100 watt charger to the phone, and it would still only charge at the 1 amp (5 watt) rate. Because the "charger" is not a charger, it is a 5 volt power source. The charger is built into the phone. There's a video in this thread that demonstrates this. It shows the power supplied by the charger on a wattmeter. And it is the same 5 watts using the 5 watt charger or the 12 watt charger.

Mr Finch I fear you are correct. I will try anyways just to see what happens since I already have it (bought it earlier in the day before I searched this thread).

One thing I felt like mentioning is that we have the wall chargers around the house. For the iPad and our iPhones. We also have a iMac we bought in 2009 or 2010 its the 27" version. Perhaps we are completely wrong but we both believe the iMac charges our stuff much faster. I just asked my wife and she believes it like its a fact. I remember last year when I had the iphone 4 me and the wife would sometimes race to use the iMac cable so we can get our phone on it.

Ill admit I didn't watch the video I ended up continuing to read the posts. Ill watch it now. My last hope for a good signal at work without killing my phone battery is to get a signal amplifier and try to get an antenna mounted somewhere high. If I can get a little better signal for 3G or even lte with it plugged in ill be happy as can be.

You can never, ever trust your "sense" of the facts. Humans have very strong biases that makes them see what they expect to see. People who say it's warmer from the iPad charger may be doing other things different, like taking it off immedately after the charge wraps up rather than waiting longer and having the phone cool. Hard science is hard.

>> One of my friends said, if a wire is a pipe, Voltage is water and the current is the pressure at which it gets the water through the pipe/wire.

You got it wrong. Voltage is the pressure. Current is the flow. You decide how much flow to draw. Drawing more flow decreases pressure somewhat.

Imagine an inflatable structure that inflates with water. It is rated for 100 gpm at 5 psi. Your faucet outputs 5 gpm at 40 psi. Can you fill it, yes, but you better be paying attention near the end. That is what charge controllers do.

>> Forget about the charging circuit for a minute here. This is a theoretical question(I am not asking you to perform it). If I pull out the battery off the phone and provide it 12v, it will most likely kill the battery

Well keep in mind lithium batteries typically have internal charge controllers. The controller would probably either shut off to protect the battery, or PWM down to the correct voltage. Assuming you bypass that... eventually yes, but you would have some small amount of time where the battery would charge very, um, robustly before it overheated. In fact this is exactly how quick charging is done. My 15 minute niMH charger has a fan on it to cool the batteries.

>>> So now you see why they sell car chargers, motorcycle chargers, and ones with variable charging rates. Please explain that one why their is not one charger for all car and motorcycle batteries.

Because copper costs money and for different modes. Burst current to assist engine cranking; quick charge but it will eventually overcharge so you must mind it; and slow charge that you can leave on 24x7. Welcome to life before charge controllers.

>>> What voltage does a car alternator put out?

Varies by accessory load and charge load. A just-cranked battery is very hungry and pulls the voltage down. Yes it pulls the voltage down on the alternator output pin. It's not all wiring losses. Once everything balances out should be 13.8v but the better regulators also compensate for temperature (I forget the rate). The best have a temperature probe inout so you can stick a temperature probe inside the actual battery box. This is more of a big deal on locomotives.

>>>> Should twice the flow be allowed by the charge circuit in the iPhone, the charge gates are wide open i.e., the charge circuit design assumes 1 amp max output but still accept a two amp flow, may induce extra heat in the battery thereby negatively impacting battery lifespan. ... The charge circuit may prevent overcharge, but may not regulate the charge rate.

No, that is wrong. The charge circuit DOES regulate the charge rate. An intelligent charge controller which does that is mandatory for lithium ion batteries. That is not the wall cube. That is inside the phone and quite possibly inside the battery itself.

If you put a low flow shower head on your shower... It will slow down flow. If I then replace all the pipes in your house with pipes twice the size, your low flow shower head flows exactly the same as it did before.

>>> Since you have such expertise answer these questions too. What voltage reading will you get on a 220 volt 3 phase piece of equipment coming in from testing supply to supply? What reading will you get testing one supply to ground? Do you need a neutral wire to use this 220 bolt 3 phase piece of equipment ?

Trick questions. You already specified phase to phase as 220v. You did not specify wye (defined by having a neutral, in the middle of the Y) or delta (defined by no neutral). On wye the ground is usually at the same potential as the neutral (220 divided by sqrt(3)...) but there is no standard for ground location, it can be any wire, phantom locations (wild leg, center of delta) or ungrounded. Ungrounded is awesome if you're trying to make 600vdc.

>>> What size light bulbs do they use for an L train that ONLY has a 600 volt power source coming in?

They used 120v bulbs wired in series in sets of five. Bulbs are specially designed to snuff 600vdc arcs.

After 1920, L-cars got a 32v battery circuit charged by a 600v MG set or chopper. Some or all bulbs run off these, these are obviously 32vdc. Nowadays they are fluorescent and are moving to LED.

You did ask :)

When I use my iPad charger on my iPhone I am visited by paisley alien creatures from the planet Zeutron.
Apple's lawyers are OK with this.

Seriuosly, though, this whole argument is ridicluous. If this were the case I would not be able to use batteries in my caera that supply higher current levels... (measured in amperes) The large ones would blow up my cam. That in itself should be the end of this thread...

He did ask. But why did you actually go to the effort to answer him? :-)

Excellent response by the way. A very good narrative indeed.

As for voltage levels on L Trains, the last time I checked, I am pretty sure I saw Apple's webpage entitled Using IPads in that address bar somewhere near the top of this entire thread.

Did anyone else notice this?

If only people were actually hard wired to look at the facts instead of continuing to assert their false beliefs on the rest of us... Well said, Michael.

Since the topic in this discussion seems so often ignored, I am going to paraphrase William Paley, the 18th-century English Christian Apologist. This quote has been misattributed very often to Hubert Spencer.

"There is a principle which is a bar against all information, which is proof against all arguments and which cannot fail to keep a man in everlasting ignorance — that principle is contempt prior to investigation."

I actually first came to this discussion believing erroneously that the charger was in that pretty empty power cube,

I actually did watch the YouTube Video, I saw soon that I was wrong, I learned a whole bunch of new and exciting stuff when I was faced with the simple truth, I have a kill a watt meter just like that real nice guy in the YouTube video had, and guess what? Mine read pretty much the same wattages as his. Lesson Learned. Next Please?

I dont think anyone is just going by their belief, they must be observing something different or else this thread wouldnt have attracted so much attention. No one is debating the fact that the Ipads charger can be used on the iphone. But every person that came in here has noticed that the Ipad charger is charging their phone at a much rapid paste and many have also noticed that their battery is draining much faster after they used the Ipad charger. When you have one person claiming this, it may not hold much weight, but there are many that came in ehre asking the same.

I plugged in two iphones one to USB and one to ipads charger, and indeed using the ipads charger is charging at a much faster pace, maybe its my USB thats not putting out but its what I have infront of me.

I also did notice after charging with the Ipads charger my battery was draining quicker, and once again confirmed by setting both battery brightness on both phones to be the same and the phone that was charged using the ipads charger was draining faster. I did a battery reset and the issue was gone and started draining at a normal pace again. These are all observations reported by many and not just one person. But yea we can use the Ipads charger as Apple claims, these are facts, the end result has caused one one of the longest threads on the floating around the internet. Why? Somehow people reporting what they observe as turned into a bullying match on here. Now the slower you charge a battery the less capacity it looses per charge cycle. This goes for any battery, consider these old things weve been taught when people are reporting they noticed their phone is depleting much faster after using the Ipads charger, rather then being so arrogant. Although Apple states you can use their Ipad charger on the iphone, after what I experienced and from ym personnel experience, I wouldn't do it unless in an emergency.