There are tons of those, claiming 15W and showing MagSafe animation on the box or product description.
But all I seen so far, and I searched, are "MagSafe compatible", or there is 7.5W for iPhones in small text at bottom. That if seller is honest. Most are not.
Is there a real MagSafe car charger, or just a holder for genuine Apple MagSafe charger? The one I just tested is 7.5W and the grip strength is also halved compared to Apple one.
I did a bit of research recently and ended up purchasing the ESR one (unfortunately a few days before the deal got published on OzBargain today). Short answer is no, I haven't been able to find any "MagSafe" car chargers (15W for iPhones), only "MagSafe compatible" ones (7.5W for iPhones).
The MagSafe chargers need to be Apple-certified (little MFi - Made For iPhone or Made For Magsafe badge or sticker) for the iPhone to actually draw the maximum power from them. Anything that isn't certified by Apple isn't a "MagSafe" charger, it's just a Qi charger (same wireless charging tech that Androids use) with the same magnet arrangement on it as MagSafe so your phone can physically attach to it. Although the charger is capable of higher power, the iPhone only draws 7.5W from Qi chargers.
So far I haven't come across any Apple-certified (15W) car chargers - not even Belkin has any! (I think Belkin usually partners with Apple to release priority accessories and are on the Apple store too - they have some 15W MagSafe chargers but none for car mounts.)
Your options are to (1) cop the 7.5W, (2) buy a car mount for an Apple MagSafe puck, (3) buy a MagSafe mount (no charging) and plug in your iPhone to a cigarette socket charger (this will probably be faster than a 15W MagSafe charger anyway). I chose option (1) and so far my phone at least stays at the same battery percentage while using Google Maps and Spotify over Bluetooth (if lucky increases by 1-2% over the course of the car ride).
This is what I mean by option 2:
https://www.google.com/shopping/product/1210514941709635033?…
or
https://www.google.com/shopping/product/9907715575160800416?…
Whatever you do, make sure you get a cigarette socket USB thing that can output the power you need :)