iPhone 6(S)(+) Lightning to USB-C Charging?

EchoSierra

macrumors newbie
Original poster
Mar 29, 2015
14
0
Boston, MA
I know that my 6S+ has the hardware to charge faster at 2.1Amps. I also know that it is too old to take advantage of USB-C Power Delivery.

If I get a USB-C to Lightning cable, will it:

1. Still charge at 2.1Amps if I plug it into a non-PD USB-C port such as on an HP EliteDesk 800 G4 (which has a USB-C 3.1 Gen 2 port, which, if I'm reading it correctly, can provide up to 3Amps)?
2. Charge at 2.1Amps if I plug it into a power bank with PD? (Specs on power bank says PD can charge at 5V/3Amps) Will the PD negotiate 2.1Amps or will it just slow charge at 1Amp because my phone can't use 3Amps?

I'm asking because I'm thinking about buying a cable to leave in my office at work (and since I could just plug it into my work computer and wouldn't have a brick, my coworkers wouldn't be able to just "borrow" it).
 

cynics

macrumors G4
Jan 8, 2012
11,554
1,873
The most all iPhones including the 6S and 6S+ support 2.4 amp @ 5volt.

iPhone 6S
Screen Shot 2020-01-12 at 6.02.06 PM.png


That is a 12 watt power source btw, 5 volt X 2.4 amp = 12 watt.

The current (amp) capacity of a port or charger is inconsequential, that is more of a testament of the quality of the charger than anything. The iPhone 6S/Plus will use up to 2.4 amps as long as the voltage is maintaining ~5 volt (12 watt). This would happen even if it was 100 amp @ 5 volt.

The problem prior to USB C is 12 watt from 5 volt dc power source down a USB 2 wire is maxing out/exceeding the spec (the reason for MFi). I could only ever get 2.4 amp charging with a high quality 6 inch lightning cable plugged into a charging station that had a the capacity to maintain 5 volt. There is an inherent difficulty moving high current with low voltage through tiny cable conductors. The slightest amount of resistance from even a the length of 3+ foot cable (even high quality) is enough to cause a voltage drop causing the iPhones iPhone to reduce current consumption to maintain 5volts.

For example this is a 5 volt 2.4 amp charger. Its capable of exceeding 12 watt (12.2). However going down that brand new OEM Apple branded lightning cable the simulated load is only receiving 10.5 watts due to the voltage dropping to 4.4v.

IMG_6989.JPG IMG_6990.JPG

That is 2.4 amp but a mobile device with a voltage regulator like the iPhone wouldn't allow the voltage drop (not good for the device). That is due to the length of the cable.

The benefit from using USB C is the chargers and cables are based on higher specs. Fast charging is technically higher voltage with lower amps (ex 18watt = 2amp @ 9volt) but even the 5 volt legacy spec are typical beefy enough to support 2.4 amp @ 5 volt and the cables have heavier gauge conductors allowing for the current to flow easier.
 

AppleHaterLover

macrumors 68020
Jun 15, 2018
2,036
2,040
It will charge faster with any current laptop. However I'd recommend getting the $19 12W iPad charger. Been using it since long before USB-C was a thing and it was not much slower than current 18W USB-C charging.
 

HEK

macrumors 68040
Sep 24, 2013
3,454
5,959
US Eastern time zone
While the information provided is factually correct, it begs the question of relevancy regarding the charging of a cell phone.

Optimizing cable type and wire diameter to reduce resistance of low voltage current would have negligible observable consequence, save for the very few super critical users.

Now if we were trying to optimize the detonation potential of a subcritical Plutonium pit in a backpack type fission device with properly designed Beryllium reflector, such attention to detailed physics would be warranted.

just saying.........💥🤷‍♂️
- - Post merged: - -

 

EchoSierra

macrumors newbie
Original poster
Mar 29, 2015
14
0
Boston, MA
The most all iPhones including the 6S and 6S+ support 2.4 amp @ 5volt.

iPhone 6S
View attachment 888239

That is a 12 watt power source btw, 5 volt X 2.4 amp = 12 watt.

The current (amp) capacity of a port or charger is inconsequential, that is more of a testament of the quality of the charger than anything. The iPhone 6S/Plus will use up to 2.4 amps as long as the voltage is maintaining ~5 volt (12 watt). This would happen even if it was 100 amp @ 5 volt.

The problem prior to USB C is 12 watt from 5 volt dc power source down a USB 2 wire is maxing out/exceeding the spec (the reason for MFi). I could only ever get 2.4 amp charging with a high quality 6 inch lightning cable plugged into a charging station that had a the capacity to maintain 5 volt. There is an inherent difficulty moving high current with low voltage through tiny cable conductors. The slightest amount of resistance from even a the length of 3+ foot cable (even high quality) is enough to cause a voltage drop causing the iPhones iPhone to reduce current consumption to maintain 5volts.

For example this is a 5 volt 2.4 amp charger. Its capable of exceeding 12 watt (12.2). However going down that brand new OEM Apple branded lightning cable the simulated load is only receiving 10.5 watts due to the voltage dropping to 4.4v.

View attachment 888240 View attachment 888241

That is 2.4 amp but a mobile device with a voltage regulator like the iPhone wouldn't allow the voltage drop (not good for the device). That is due to the length of the cable.

The benefit from using USB C is the chargers and cables are based on higher specs. Fast charging is technically higher voltage with lower amps (ex 18watt = 2amp @ 9volt) but even the 5 volt legacy spec are typical beefy enough to support 2.4 amp @ 5 volt and the cables have heavier gauge conductors allowing for the current to flow easier.
My main question is; with the Apple USB-C to Lightning cable, will USB-C-PD support the legacy spec and max it out giving me the most current that my phone can handle, and will the USB 3.1 Gen 2 spec without PD do the same?
 
Last edited:
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