iPhone 7/Plus Equal spec chargers charge at different rates?

[lorkp]

I charge my iPhone 7 with the following:
a) MBP 3.0 USB port—up to 2100 mA (the iPhone gets "extra operating current")
b) standard iPad charger—up to 2400 mA
c) Anker car charger—up to 2400 mA

All can charge at a speed higher than the iPhone will receive. My phone is jailbroken and I've observed the charging rate through the BatteryLife app. I noticed that the MBP is pretty conservative—maybe 1100 mA usually—while the iPad and Anker is more aggressive—1300-1500.

The MBP seems to take in account overall juice going to the phone, i.e. if the phone is doing something intensive, or if the brightness is cranked, the charge rate goes down. The iPad charger does this too, but the overall cap seems to be higher. The Anker charger is the "dumbest" and charges at a relatively constant rate no matter what.

Anybody have an idea as to why? With some chargers, can the iPhone more intelligently "ask" for power in the interest of protecting the battery or something?

Thanks

 

[jav6454]

iPhones that do not have fast charging cap their charge rates at 1A. Doesn't matter if you use a charging with a higher capacity. Your mileage may vary on other factors such as battery drain state. A more drained battery tends to charge faster than a battery with more juice left in it.

 

[cynics]

Normal. However there is a bit to know...

USB standard is 500mA from a computer for charging, or at least it used to be the standard. This would protect the computer from legacy devices that were capable of drawing more power than they should.

Macs can bypass that limit based on a request from an iOS device from 500mA to 1100mA. This is why a PC couldn't charge an iPad, at least very well but a Mac can and its also the reason you see exactly 1100mA which is its max it will charge.

2100mA is going to be total capacity. So if you have multiple devices plugged in you get a max of 2100mA collectively.

iPad charge and Anker are being limited at the iOS device itself since there is very little "logic" in the wall wart.

Aside from that their a lot of variables like mentioned, from current charge state and temp to the cable being used itself.