MagSafe 15W fast charging restricted to Apple 20W adapter

Post by didntlogin » Tue, Oct 27, 2020, 11:59 AM UTC

Post by ksec » Tue, Oct 27, 2020, 2:20 PM UTC

Post by ksec » Tue, Oct 27, 2020, 2:32 PM UTC

detaro wrote: post #4

ksec wrote: post #3

I have yet to find a valid answer I hope someone on HN could share some light on this. Apple needs some explaining to do, especially when they try to sell it as Environmental friendly to not include an adaptor.

One guess could be the power delivery profiles: USB-C PD has options for 5, 12 and 20V, and I don't know how common support for the 12V modes is in chargers. If the device insists on 5V or 12V, and most chargers don't support 12V, that'd explain it falling back to the 10W/5V mode. I'd expect some tech reviewer could easily test that by making sure to try a charger that does 12 V.

Post by detaro » Tue, Oct 27, 2020, 3:00 PM UTC

ksec wrote: post #5

detaro wrote: post #4

Earlier quoted context omitted.

One guess could be the power delivery profiles: USB-C PD has options for 5, 12 and 20V, and I don't know how common support for the 12V modes is in chargers. If the device insists on 5V or 12V, and most chargers don't support 12V, that'd explain it falling back to the 10W/5V mode. I'd expect some tech reviewer could easily test that by making sure to try a charger that does 12 V.

The 20W Charger is 9V / 2.2A, and the 15W Charging seems to be limited to this ( I am assuming the 5W deduction is due to induction inefficiency ) Having a higher profile such as 9V 3A should have worked, especially with PPS, but testing so far indicate MagSafe fails back to 7.5W.