AUKEY 20W Charger on a MacBook Air: Measured
AUKEY's 20W charger measured on a MacBook Air M5: 18.9 W delivered over an uncommon 12 volt rail, plus a PPS range for phones.
AUKEY’s 20W USB-C charger, tested against a MacBook Air M5 with a low battery, per the methodology.
The numbers
| Rated | 20 W |
| Negotiated | 20 W (12 V up to 1.67 A) |
| Live draw | 18.9 W (11.9 V at 1.59 A) |
| Protocol | USB PD 3.0 |
Profile menu:
| Profile | Rail |
|---|---|
| 15 W | 5 V up to 3 A |
| 20 W | 9 V up to 2.22 A |
| 20 W | 12 V up to 1.67 A - active |
| PPS | 3.3-11 V, up to 2 A |
The 12 volt rail
The active contract here is 12 V, which is unusual. Most chargers at this size step 5 V → 9 V → 15 V → 20 V and skip 12 entirely; the Apple and Anker 20 W chargers both top out at 9 V.
AUKEY publishes its full 20 W twice - once at 9 V / 2.22 A and again at 12 V / 1.67 A - and lets the device choose. The Mac took the 12 V rung.
Same power either way. The difference is which voltage the device’s internal converter prefers, and offering both means the charger doesn’t force that decision.
The PPS entry
The final line is a range rather than a rung: PPS, 3.3-11 V, up to 2 A. Programmable Power Supply lets a phone request a precise voltage in 20 mV steps to match its battery’s charging curve, so less of the delivered power is lost as heat inside the device.
macOS doesn’t use PPS - it charges from the fixed 12 V profile instead.