Question Wireless Chargers

Dylan Beckett

Respectable
Jul 12, 2021
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2,245
Hello

Please note - I've never used Wireless charging - ever.

I've read manuals for some gadgets saying that you shouldn't charge things like Android phones and/or True Wireless Headphones.....

A) On the same Wireless charging pad as another item (or more than one other item) at the same time; and/or
B) You shouldn't have Wireless charging pads anywhere near each other (at least 30 cm way from each other); and/or
C) You should have them far far away from damn near anything electrical, or with Radio/Wifi/Bluetooth signals - TVs, Phones, PC's, damn near everything?

As I mentioned in another thread - is this just covering themselves legally or is there something to this?

For your replies - please list which letter above - you are referring to - I would really love to hear what you think about all 3x as I don't know what to believe as it sounds over the top ?

I need to know as I plan to buy some Wireless charging pads for myself, and my family and I was intending to get Wireless charging pads that can charge multiple items at once.

So, is this a bad idea, or not?


So, I might want to charge all of these at once; or a combination of these at once on the same pad
e.g., 1-2x Android phones, True Wireless Headphones, and a Wireless Guitar tuner etc all at once (or a myriad of other junk I might buy) etc.

I want Fast Charging ideally - is this a problem with lots of devices?
Does it divide/share the charging power for every item you add?

Is there some term to clearly state that a Wireless Charging pad can charge multiple items or specifically 'this many' at once - e.g. something equivalent to MU-MIMO for Routers?

I assume most Wireless Charging pads have their own power adapter; is this better than using USB from a PC or something else?
Is it ok to buy USB Wireless Charging pads?


Any advice on what to look for, what to avoid and any quirks I need to know - please let me know!


Thank you for your help
 

Aeacus

Titan
Ambassador
A)
Those wireless charging pads are designed to charge one item at a time. Putting several items at once on them, drops the current too low, whereby it can interrupt the entire charging and also damage the chargers/batteries of the charged devices.

Unless the wireless charging pad specifically states, that several devices can be charged on it at once, don't do it. Or you can disregard this warning, do it, get lucky for a while, until something pops and releases the magical smoke.

B)
Reason: EMI interference.
Further reading: https://www.techtarget.com/searchmobilecomputing/definition/electromagnetic-interference

C)
Same reason as with B).

Any advice on what to look for, what to avoid and any quirks I need to know - please let me know!

Further reading: https://www.wired.com/gallery/best-wireless-chargers/

Saw quite a few dual- and triple-wireless chargers there.
 
Personally I don’t wireless charge anything that isn’t through a magnetic connector. The efficiency of Qi isn’t very good once you start misaligning the coils and without something to latch the coils in perfect alignment ( like MagSafe) you’re just losing power. Even with perfect alignment you’re talking 75% efficiency, without it you’re talking 50 and lower.
With fast charging too you have to remember that near all the wastage power exits as heat which is bad for your battery. So if you’re charging at 40W you’re looking at getting 20W of charging with 20W of heat.

Most pads I’ve seen just use USB