iPhone Wireless Charging speed

[Walter_Kai]

I observed a strange phenomenon that I want an answer to:

 

Using a 2A output USB brick or whatever you call it, I got the following observation

- Using a lightning cable, charging current is about 0.9A

- Using a wireless charging pad (let's call it charge pad 1) with ratted output of 10W, the charging current is about 0.4A

- Using another wireless charging pad (let's call it charge pad 2) with ratted output of 10W, the charging current is about 0.5A

 

The strange thing is, I sometimes observe using charge pad 2, the charging current could hit 1.5 to 1.7A, there seems to be something limiting the current when I am using wireless charging often now and then, and I just don't know why.

 

 

Update 1:

The current seems to increase if I place the phone (and the charging pad of course) further away from the power source, let it be the USB power brick or a mobile power bank.

This explains why the wireless charging pad I use at my bed seems to charge the phone just fine everytime, that charging pad is about 2m away from the USB power brick.

I know wireless charging works on magnetic induction, but could the magnetic interference near the power source really be that significant?

 

[Altruist]

Idk if this will help, but doesn't output decrease as the phones nears 100% charged

[Walter_Kai]

2 minutes ago, Altruist said:

Idk if this will help, but doesn't output decrease as the phones nears 100% charged

Yeah it does, I heard it stops at 80% if it gets hot, but this strange habit happens even when my phone is down to like 20% or less

So I don't think so

[MacBook1]

Case maybe?

[Walter_Kai]

6 minutes ago, MacBook1 said:

Case maybe?

Nope, I tried it with and without the case, and this still happens in the exact same way.

[MacBook1]

How odd.