No problem!
While the Powerport III Duo should work fine with the MagSafe charging puck, it will likely charge at a maximum of about 13w—not the full 15w.
That's because on their spec page for the product, it shows that it outputs 9V-2A (18w)—while to charge at the full 15w, the MagSafe needs an adapter that puts out 9V-2.22A (20w). That's a new spec: 20W Power Delivery 3.0
Fast Charging: Charge an iPhone 12 or iPhone 12 Pro to 50% in just 25 minutes—that’s up to 3× faster than with an original 5W charger. Wide Compatibility: Works flawlessly with a wide range of mobile devices including phones, tablets, and more. Travel Ready: Designed to be taken anywhere with a...
us.anker.com
View attachment 1885214
There's an article about the adapter requirements here:
Alongside the iPhone 12 and 12 Pro models, Apple introduced a new MagSafe charger that attaches to the magnetic ring in the back of the devices,...
www.macrumors.com
And there may be some 3rd-party adapters that put out the full 20W as 9V-2.22A, such as:
Designed for iPhone: Provide full-speed 20W charging for the iPhone 13. High-Speed Charging: 20W USB-C charging gives you the power you need to charge up your iPhone to 50% in just 25 minutes—that’s up to 3 times faster than your old 5W charger. Advanced Safety Features: Equipped with our...
us.anker.com
https://us.anker.com/products/a2038 (this is the same as above, but with 2 identical outputs)
And cheaper ones:
20W USB C Plug Power Brick for iPhone 16/15/14/13 Pro Max/13 Mini/12 USB C Plug in Wall Charger Specification Input: AC 100–240V 50/60Hz USB-C Output (PD 3.0): 5V 3A 15W, 9V 2A 20W, 12V 1.5A 20W Total Power Output: 20W USB C Wall Plug Fast Charger Identification Type c wall charger compatib...
www.amazon.com
USB C Charger 20W, Wall Charger Fast Type C Charging Block Durable Compact with PD & QC 3.0 USB-C Adapter Compatible with iPhone 13/12/12 Pro Max 12 Mini, 11 Pro Max, AirPods, iPad, Switch
www.amazon.com
This USB-C charger packs a total of 32W power features a foldable plug for easy portability and storage. Keep your devices charged at home, in the office, or travel. Built-in multi protection effectively protects your device from over-voltage, over-current and short-circuit, ensurin...
www.amazon.com
The Watch Series 7 requires a minimum of 5w PD, according to this:
The Apple Watch Series 7 includes a new charging architecture that allows it to refuel up to 33% faster than the Series 6, charging from 0 to 80% in...
www.macrumors.com
But all that said, I have to say that I don't see a huge difference between using MagSafe on an 18w v. 20w adapter—when charging the iPhone, it really only hits the peak charging speed for part of the charge, and I'd be curious to see the actual difference between 13w v. 15w for a full charge. It's more likely to boost things when going from 0-50% or so. These people found less than 5 minutes difference:
Now that Apple is the IKEA that forces you to make your own charging set, check out how fast would the iPhone 12 and 12 Pro be charged with your ol' 5W and 18W chargers, Apple's new 20W charger, and the fresh MagSafe puck.
www.phonearena.com
What is the fastest iPhone 12 and iPhone 12 Pro charger? Is it Apple's new 20W charger, or even its 61W USB-C adapter? Can I still charge the iPhone 12 with my 18W iPhone 11 adapter and will it be as fast as the 20W brick?
www.phonearena.com
And if you're really in a rush to charge your iPhone, you're not going to use MagSafe anyhow: a Lighting cable will be under an hour from 0-80% — more than twice as fast!
Hope that helps!