An iPhone X wireless charger upgrade

for the Quad Lock Pro Bike Phone Mount

Having done a lot of long distance cycling, my phone battery often gives up early. In dry weather, I can charge it on the move with a simple USB cable/charger. When the weather turns for the worst, the charge connector can quickly get wet/contaminated leading to intermittent charging. There is nothing worse than seeing a "battery low warning" when your legs are already about to give up!

Update on iPhone 12

After two years of reliable operation with my iPhone X, I have recently upgraded to an iPhone 12 and found the charger does not work. It seems that the 12 is less sensitive when initiating a connection and I have found it unreliable on other commercial chargers as well. Reading around, this is a common issue - maybe Apple forcing the use of their proprietary Magsafe system?!

I plan to experiment with the distance from coil to phone as I think this is the key parameter and may need to change the charger board. I will update the design once working again.

Instructions

This module replaces the blue part of a Quad Lock Bike Mount Pro which can be bought for around £25:
https://www.amazon.co.uk/Quad-Lock-Bike-Mount-Only/dp/B008O0USLO).

It allows an iPhone or other phone supporting Qi Wireless charging to be continuously charged simply by attaching it to the mount. No need to plug anything in and the legendary secure locking action is maintained with the charger able to be pushed down to unlock the phone.

The Qi Wireless Charger PCBA can be purchased from Amazon for ~£7:
https://www.amazon.co.uk/gp/product/B07DC3JL89

The Quad Lock's plastic shaft is just the right size to fit insider the coil (18mm) but the black magnetic shield will need to be opened out to enable this. I used masking tape and then nibbled away with small handheld cutters to avoid cracking the brittle ferrous material.

Clean the PCBA and coil thoroughly with isopropyl alcohol and then apply multiple layers of nail varnish to seal, protecting them moisture/contamination/humidity.

The coil and charger PCBA should fit snugly inside the housing. Fit a USB cable and then use a glue gun to fill all remaining space and to glue the two halves together. Once cooled, remove any excess with a sharp knife. Apply a number of layers of clear nail varnish to fully seal the enclosure, particularly in the central hole where the shaft will pass through.

###To install it on the mount:
Remove the metal screw from the middle of the Quad Lock mount and take off the top black part, blue part and spring. The spring will need to be cut to about half its original length due to the thicker charger - remove small amounts until it feels right. Replace the top black part and use an M5 nylon screw and nut (inside the body - peel away the rubber to access) to hold the parts together securely.

*** IMPORTANT ***
Make sure you replace the original metal screw with one made from plastic (e.g. https://www.amazon.co.uk/gp/product/B01HY2ZCBI) Due to the inductive method of charging, a metal screw (ferrous or not) will rapidly heat-up and focus the field in the centre and could lead to damage to your phone! I damaged the NFC on my own phone before realising so be warned!!

###Design
The parts were designed using FreeCAD - my first time using the tool and I was impressed at how easy it was to use.

The parameter based approach was very useful for getting the precise dimensions for the latch and for snugly fitting the wireless charge module.

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