[YotaPhone] Amplificator:
My answer is based on simple physics.

Just because the amps are lower doesn't mean it's not bad for the battery.

Wireless charging is way less efficient than any form of wired charging.

What happens to the loss? Well, it gets dissipated as heat - and what is the "big killer" of lithium batteries? ..heat.

For this single fact alone, denying that wireless charging causes more harm than a cabled charging is simply.. well, silly.

The only ones denying this are either unaware of simple science or are lying to you, probably to sell you a charger :p

Yes, every form of charging, even at a theoretical 100% efficiency will heat up the battery due to chemical reactions inside the battery, but the lower efficiency you have the more energy is converted into heat - thus you do more damage and getting even less actual battery-energy out of it.

Simply put: the best charging method is the one that produces the least amount of heat while maintaining a high efficiency - wireless charging is simply not that.

Charging using a cable at 90% means 10% is being converted into heat (not all 10%, but for arguments sake, play along), where as using wireless charging might be at.. 50% depending on different circumstances (probably a lot closer to 70% than 50%, but again, for arguments sake).

This means that the other 50% is just turned into wasted, unnecessary and unwanted heat.

The percentages obviously aren't correct in this example, but it's more to get the point across.

With wireless charging you do more damage (it is subjective as to whether this matters to you) to the battery than you would by using a cable, simply because you create more excessive heat which only purpose is to heat up the battery and surrounding area than actually going into the battery itself.

If we consider the 50% efficiency of the before mentioned example, this means that you would need to charge your device for almost twice as long time as when you use a cable. Not only does it create more heat by virtue of being inductive charging, but it will be doing so for, again, almost twice the time length.

Efficiency also depends on things like distance - the less "perfect" your phone is placed on the charger the less efficient, and thus more wasteful it is.

Google something like "qi wireless charging overheating" and you will see plenty of people reporting on overheating problems when using wireless charging. This is because of all this wasted energy that is dissipated as heat - instead of "filling" the battery it simply heats it, and the surroundings, up.

Despite being made to the same specs, this seem to differ from charger to charger, such as this thread here on XDA would indicate: http://xdaforums.com/google-nexus-5/help/post-qi-charging-battery-temp-t2544768

If you look at the version specifications you see that version 1.2 of the "low power" Qi charging branch which phones are a part of increased the power to up to 15W.

Unless they also worked on the efficiency this would actually mean that version 1.2 does more damage to the battery than 1.0 and 1.1, but for that you would have to dive a bit deeper than the information given in that link.

But as always it's sort of subjective as to what point people will see wireless charging as being too wasteful and/or damaging.

Personally, I don't care because the convenience of wireless charging by far outways the little damage it does to a battery, in my opinion, and the same goes for QuickCharge as well. By the time I would see a noticeable effect on battery life I have probably already bought a new phone anyway :)

If we take Qualcomms QuickCharge for example,I think QC 3.0 is at the point of where people shouldn't really care about the negative impact. If you read the spec sheet for QC 3.0 it's basically a tweaked version of QC 2.0 (well duh) where the power delivery is controlled much better than QC 2.0 was, bringing both the efficiency and therefor speed to a much higher level even though both are rated for 18W.

Some reading for those who still doubt basic physics :p:

http://batteryuniversity.com/learn/article/charging_without_wires

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

http://batteryuniversity.com/learn/article/all_about_chargers

http://batteryuniversity.com/learn/article/ultra_fast_chargers

..and the best of all: https://google.com/ :)

But let me ask you the same question you asked me; and I quote:

..that probably sounded very condescending (which is not how it was intended, of course), but I'm curious as to where you've acquired this absurd idea that Qi wireless charging is the best method of all? It's very likely the worst of all, actually.