[Nexus 5 Accessories] pedxing:
I can't take credit for the idea, a number of people in the forums have done something similar. But I thought I'd document my build so others could follow along.

The concept is to have a nice qi wireless car dock but with a twist. Utilizing the small metal disks in the back of the nexus 5, we can make the whole thing lock on magnetically. True one handed operation with no wires.

Here's what you need:

One small qi wireless charger like the lg wcp300. (I also tried the goosewhite charger but it was dead on arrival).

An old or new car mount that can be adapted.

Four half inch by one sixteenth inch neodymium magnets. I picked up 10 from amazon for $6.

Black plastidip spray (available from home depot or Lowes).

(Possibly) a small amount of household sealant to smooth any rough edges.

Epoxy or strong glue

Double sided tape

Tools:

Electric drill or dremel tool

Screwdriver

A vise is convenient

Calipers or a good ruler

OK. So here's what we're going to latch the magnets to:

The disks are in a line down from the camera lens...25mm from the lower edge of the lens to the center point of the first disk. From there all the disks are in a square 36mm on a side, center point to center point.

This is important because that's where you have to place the magnets on the charger.

Next let's look at the charger.

OK now let's mess that little guy up.

First let's see how thick the plastic is that the top is made out of. My idea was to drill into it so that magnets can rest flush.

If you peel back the little feet you get access to four screws.

Now we can open it up.

I quickly learned that on this charger there was no room between the qi coil and the case to place the magnets in the inside. So on to plan b. I measured the plastic and found the thickness was under 2mm. Hmmm. The magnets are about 1.6 mm. Not a lot of room to maneuver. I decided to go for putting a groove into the top of the case for each magnet. This would at least minimize the distance between the coil and the phone as much as possible which should lead to optimum charging.

With a pencil, I marked the center points of each magnet location and started making my grooves.

I free handed the above with a small grinder bit on my drill. The bit wasn't a half inch so it got a little rough at times but it was doable. Here the magnet in the groove.

The magnet sits in the groove about half way... All I had to do was remove about one thirty second of an inch of plastic for four slots.

The above shows how only a small amount of the magnet is not flush. It's really close to flush.

Here's that step done. It's a little rough but not too bad. Glue each magnet in with a dab of epoxy or gorrila glue or whatever you have handy.

So now let's polish it up. If your grooves are pretty then you won't need the sealant...I put some on to smooth out the edges. Sorry didn't get a pic of that step.

Now let's get ready for the plastidip.

If you've never used it, it's great. It's a spray on rubber that will give the charger pad a non slip texture to ensure the phone won't slide off even on the most bumpy roads. The half inch magnets are quite strong but we're talking sheering force here. You need some grip. The half inch size helps also due to increased surface area.

First let's tape off the bottom.

And start spraying.

Pro tip: the hand spray attachment is awesome. So let's see what we got.

This is four light coats.

Next I used a mount I had from my gnex days and never could sell. Some dremel work later and presto a nice sized mount.

To attach the charger I opted to use some 3m auto trim tape. This is super strong and heat proof. Also it's reversible unlike epoxy. A little dental floss sawing between the two pieces and the charger is removable.

A couple of strips and we're done.

And here it is with the nexus 5 on it and charging.

Thanks and let me know if you have any questions.