Apple Airpods Pro not charging on a wireless charger - solution

Hello, everyone!

I had this problem that Apple Airpods Pro did not charge on an off-the-shelf regular Qi compliant wireless charger. It charges for a minute, but then the charger starts blinking red error, and Airpods stop charging.

However, it happens so that I am an electronics engineer, and I was building a wirelessly-chargeable wristwatch at the same time, and I experienced the same problem with my device. After communicating this problem with guys from Wurth Elektronik, who also make wireless charging coils, we figured out where the problem is. If the charging coil is much wider than the device, the wireless energy goes around the device and heats it up from all sides. The device heats up to over 45*C, and its thermal protection triggers, halting the charging process to prevent Li-Ion battery from damage. Therefore you have 2 options.

1. Buy a smaller wireless charger that has outer dimensions approximately the same as your Airpods Pro case. You can find such chargers on eBay, they have a special shape where Airpods Pro case fits in perfectly. In a smaller charger, there is a smaller coil which makes a more narrow, focused energy field which goes straight into Airpods' charging circuitry, instead of going around it.
2. If you already have a regular wireless charging pad, put some non-metallic padding between it and your Airpods Pro charging case. 2-3mm should be OK. This way you locate your charging case further away from this strong field, so it gets weaker and heats your device much less. Charging circuitry still gets enough energy to charge, it just does not overheat.

BR

Andris