That's simply not technically possible.
If you put 2 x 5S' side by side that were both on 0% charged, and you started charging them at exactly the same time, one with a standard 5w charger and 1 with a 12w IPad charger, they'd both reach 100% at pretty much the same time.
A 5S that charging faster using an iPad charger is simply placebo.
Yes, because that's
by design. It has the internals to draw a higher charge, unlike any iPhones before it.
Correct, but that's just simply because if you're using it, you're draining what you're tyring to replenish (like drinking a glass of water through a straw, while somebody is trying to fill it up).
You stop drinking, the level goes up faster.
It most certainly is technically possible, given the following conditions. I agree with your first scenario, that no difference will be seen if
all you are doing is charging the battery. That is if the two 5s iPhones are turned off, they both will charge at the maximum allowed which is at the smaller charger's rate and nothing more, by design. However my point, to which you agree in your later point, is that with additional draw from radios, phone, data, gps, that happens in background. The smaller charger does not put out enough to both charge battery at max and run other features. Depending on what apps you have, and how they are set, there can be a lot going on in standby. Calls are being made, data passed back and forth as the phone sits quietly trying to charge. Point in fact, most people would be surprised at how much their phone may be doing, spilling it's guts so to speak without you realizing it.
Since most people will charge their phone in standby, they will see a faster battery recharge using the iPad charger. The iPad charger has enough output to both charge battery at the maximum 5s rate and run radios, gps at same time in back ground.
That is why, I and others have witnessed a faster recharge of the 5s using the iPad charger. This is not a placebo as you suggest. I had measured this when I still had my 5s, and I did not imagine the results. Also note that this will vary due to each individual's location, situation. If you have many apps doing things in back ground during standby, and have apps that broadcast gps in standby, and are in a low signal area such that phone's radios need to broadcast at higher power. That situation will show the most reduced battery charging time using iPad charger because so much power is being consumed from the normal charger on non-battery functions little power is left over for actually charging the battery.
In a sense both parties are correct when saying the 5s does not charge faster, and that it does charge faster using iPad charger. It depends on what else the charger is supporting during the charge. A purist may argue that maximum charging capability for 5s is the 5-6W put out by iPnone charge cube, which is true. Yet the iPad charger WILL IN FACT charge batteries faster under normal (phone in standby) charging conditions because it has enough capacity to power all other function while simultaneously charging the battery at maximum rate. The iPhone cube charger DOES NOT AND CAN NOT both charge at maximum rate and run radios at the same time, and will take longer to charge the batteries under this, usual for most, situation.
For those people placing current draw meters on their charge cable, they also must keep this multiple use of current for charging and radios in mind. Also be aware that battery charge demand by the IPhone circuits varies depending on battery charge state. The phone will demand the full allowed current when battery is very low, 0-5% and will reduce this draw as battery becomes more fully charged. At near 100%, the draw will cycle on and off at just a trickle charge. Apple has engineered the phone, Chargers, and cables to maximize battery life, and idiot proof the charging. You won't hurt your battery, using iPad charger, nor help by only trickle charging. All the charging options allowed are well within best charging practices for LI batteries. Battery University discusses scenarios at extremes of charging, which Apple design does not get anywhere near. The one thing to watch is temperature. Charging with iPad charger, when battery is very low, while playing processor intensive game, with full screen brightness, while Facebook is messaging every 30 seconds in a low signal strength area, will turn your phone into a nice heater. Bad for any LI battery. Have it in a nice tight case to boot and I dare say this is not friendly to your battery life. ��
