After my HTC One M8’s conversion to the Church of Wireless Charging Only, I decided I wanted to charge even faster. I have a couple of 2 amp wireless bases and a couple of 1.5 amp bases, and my phone is capable of charging at about 970mA on a good wall charger (more if they’d release the quickcharge 2 chargers in the US,) so I set out to find higher capacity receiver coils.

This is a piece on the only three aftermarket USB wireless charging receiver coils I could locate that claimed to be over 500mA. The vast majority of coils just say that they’re a receiver coil, or that they’re 500mA or below.

Receiver coils I own

QI specs that aren't trueGhosts of Chargers Past

We’ll start with this gem from Amazon which claims a charging current of 500mA-1000mA (text on right is a screenshot from the Amazon page). You would be lead to believe from that that this is a 1000mA receiver coil. Nope.

Output is clearly listed on the product as 500mA (see other photo below). Output from the product is about 440mA. It can take more than 500mA input from the receiver, but it’ll only give the phone 500mA.

Cheap-o 500mA receiver coilThis is the product I learned that these things are deceptively labeled – the receiver coil can receive up to an amp, but charge like a slug at 500mA. The charging current you would assume to be the charge that it will deliver, but no.

Unfortunately, most people getting this product will believe that this is just a limitation of wireless – that it’s slow. It’s not, this is just deceptive advertising.

You can charge at full tilt with wireless, just not with this junk.

Bluestar charging on me….

The next is a Qi charger labeled “Bluestar” that claims an output of 1000mA on both the website and the back of the product. I’ll admit I got this a bit because I used to work for a company called Bluestar in Nashville (business ISP), what I should have realized was with that name no good could come of it.

After miserable charge rates on a few devices, I laid this product directly onto four charging bases (sans cases,) and I was lucky if I got 400mA. With the case I was still in the same neighborhood, but this supposedly 1000mA charger was getting less.

Day three of testing it I was getting notice that my HTC One M8 was drawing more power than it was receiving while the screen was off and nothing was active. That’s a charge rate of under 50mA .

The Bluestar receiver coils seem to be sold exclusively at dx.com. I contacted them about two issues – the first that it took nearly a month to show up (this was before it came), and the second issue that it didn’t get half of what it was advertising.

I was informed that 400 out of 1000 was enough for daily use; I told them if they felt that way they could buy it from me as it now took longer to charge my phone than the amount of time I can have it on the charger while sleeping. I got offered a couple of bucks, several emails later and an offer of $4 in dx.com credit (which I’m not shopping at again). I’ve given up on a refund of my $8.something and just posting this here. Don’t buy it.

KR-net to the rescue

The KR-net coil I got came with a case and is not sold any more that I can find. If I’m not mistaken, it’s this receiver coil. It advertises 750mA charging and I’ve now seen it reach 90% of expected. It’s the first coil I got, it’s the one I wanted to ditch for a faster coil, but it works.

Depending on case and orientation (I’ve got an upright wireless charger too), I’ve noticed it can get warm, but it’s never been hot to the touch or warmer than if it were left in a pocket for a while.

Wrapup

That’s it for now. If you run across any aftermarket Qi receiver coils that are one amp or higher, drop me a line. The ability to drop a phone into a charging state while driving and never having to look down to plug in a cord is one of those things I do not want to be without again, but I’d like over 750mA as I also don’t want to be charging for several hours.