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[HOWTO] Make your own magnetic qi car charger dock

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By pedxing, Senior Member on 18th November 2013, 01:49 AM
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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

Electric drill or dremel tool
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.

Sent from my Nexus 5 using Tapatalk
Last edited by pedxing; 18th November 2013 at 02:22 AM.
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18th November 2013, 02:42 AM |#2  
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Nice work. Thanks for the pictures and the walk through. Would like to see some pictures in the car when you install it. Have you been able to find a 90 degree angle micro USB connector so you can possibly hide the USB cord? Looks nice though. The best one I have seen yet.
18th November 2013, 04:40 AM |#3  
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Great mod!

I was looking at the picture of the phone. Do you know how big the magnets/metal plates that are surrounding the charging coil? I want to do a similar mod, and I was thinking of getting magnets that are the same diameter as the ones on the phone itself.
18th November 2013, 06:45 AM |#4  
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Great post. I'm really not the DIY type, so I might struggle sinking the magnets in, but I really want a magnetic car mount, so maybe I'll try...
18th November 2013, 07:23 AM |#5  
bradputt's Avatar
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wow, what a simple and elegant way.

no more clamps and stuffs.

good one~~!!!!
18th November 2013, 07:32 AM |#6  
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Microscopy gromean
Great post!!
18th November 2013, 02:09 PM |#7  
pedxing's Avatar
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A couple of more pics from inside the car...

To answer questions:

I think the metal disks in the phone are 10 mm diameter. I believe that quarter Inch magnets would work fine.

I was planning to hardwire the USB cable but switched fuses are few and far between in my car. I used the last one for my radar detector. Maybe I'll vampire off of the cig lighter port that's already there.

Sent from my Nexus 5 using Tapatalk
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18th November 2013, 03:26 PM |#8  
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Originally Posted by pedxing

A couple of more pics from inside the car...
I think the metal disks in the phone are 10 mm diameter. I believe that quarter Inch magnets would work

BAsed on the FCC photos, the disks are 6mm in diameter.

They are between 36 and 37mm apart, at their centers.
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18th November 2013, 06:52 PM |#9  
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Very nice job! I will build one of these attached to a RAM ball so I can use my existing mount. I much prefer the one handed operation. But I will build it sans charger.

But a word of caution... I built an in vehicle cradle out of a WCP700 last year about this time. Come Summer, it was unusable to charge the phone under heavy use (screen and GPS on). Battery temperatures just got too high. Unless you can mount it in a location where the A/C can directly blow on it for cooling, you will prematurely toast your battery. I think there is a very good reason why OEMs don't offer one of these fro their phones.
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18th November 2013, 07:17 PM |#10  
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How good do the magnets hold it? I don't want my phone flying off it if I hit a pothole

Sent from my Nexus 5 using Tapatalk
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