Using the GRL-C2 USB PD Tester and GRL-PSP Power Analyzer software from Granite River Labs, we can see that the downside of shrinking the size is a much higher temperature. The maximum temperature of the Anker PowerPort PD Nano 20W Charger is a very uncomfortable 69.9 degrees C while the Apple 20W USB-C Power Adapter hits 56.4 degrees C. Anything over 50 degrees C can potentially cause burns depending on how long the skin is exposed to that temperature, so definitely be careful with the Anker PowerPort PD Nano 20W Charger when it gets that hot.
Also, unlike the Apple 20W USB-C Power Adapter, the Anker PowerPort PD Nano 20W Charger also does not recover quickly after an over current protection (OCP) event, meaning that a device that accidentally triggers OCP may not be able to recover and continue charging.
The Anker PowerPort PD Nano 20W Charger is great if you need something small and portable while on the road but the Apple 20W USB-C Power Adapter might be better at the home if there are young children around and you are concerned about them touching hot objects.
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