Testing Apple Chargers & Adapters: Wattage Performance Results

[BSPBSP]

Let me preface this by saying that I am aware of the tests regarding slow vs fast charging effects and that the savings of slow charging might not outweigh the convenience gained by using fast charging.

In any case, as of today, Apple is selling quite few adapters, charge cables, and pucks and I was curious what charging wattage the difference adapters would produce, so I tested the ones I have after I was unable to find specs for some online.
I tested these for iPhones, Apple Watches, iPads, and Macs with consistent results.
The following accessories were involved in the tests:
- Apple USB C to USB C Cable (1m)
- Apple USB A to Lightning Cable
- Apple USB C to Lightning Cable
- Apple USB C to USB A Adapter
- Apple Lightning to USB C Adapter
- Belkin USB A to USB C Cable

Please see table below for configurations and outcomes for iPhones, iPads, Macs:

Charger Wattage	Charger Side Adapter	Cable	Device Side Adapter	Output
5 W	-	USB A to Lightning	-	5 W
5W	-	USB A to Lightning	Lightning to USB C Adapter	5 W
5 W	-	USB A to USB C	-	5 W
12 W	-	USB A to Lightning	-	12 W
12 W	-	USB A to Lightning	Lightning to USB C Adapter	12 W
12 W	-	USB A to USB C	-	8 W
20+ W	-	USB C to USB C	-	20+ W
20+ W	-	USB C to Lightning		20+ W
20+ W	-	USB C to Lightning	Lightning to USB C Adapter	20+ W
20+ W	USB C to USB A Adapter	USB A to USB C	-	8 W
20+ W	USB C to USB A Adapter	USB A to Lightning	Lightning to USB C Adapter	5 W

For Apple Watches, the results are much simpler:
All USB C charge pucks enable fast charging of Apple Watches up to 5 W.
All other charge pucks with USB A (no matter if metal of plastic) charged up to 2.2-2.3 W with all Chargers (5, 12, and 20+ W with USB C to A Adapter) *measurements fluctuate significantly more than the ones above for Macs, iPhones, and iPads

Pending: Seeing that the Lightning to USB C Adapter can push 20+ W, I want to test its maximum throughput.

 

[Slartibart]

like to share your testing hardware specs?

 

[chown33]

What was used to measure output power?

 

[BSPBSP]

Certainly!
I used a power meter on the charger side to measure the input (manufacturer states accuracy of 0.2% down to the tenth of a Watt) and checked it agains the power the receiving devices negotiated as input (e.g., Mac System Info AC Charger Information).

All of the measurements lined up except one, the chain [[12 W >> USB A to Lightning Cable >> Lightning to USB C Adapter]] showed 12W on the receiving end but kept fluctuating between 12 and 13 W on the input side.

Given that the adapters most likely also consume a non-negligible amount, the actual power on the receiving end could be slightly lower as well, but that was an acceptable factor for my use case since I wanted to know how slow each configuration charges.