What is the best way to charge my phone 14 pro in the car without ruining the battery

Howdy! The best answer is "however you'd like", as long as you don't expose the phone to high temperatures. So a wireless charge phone mount, plugging it into the car's console, whatever. The iPhone is very clever with charging. It only draws as much power as it needs, and once it reaches 100% it stops charging, only trickling more power now and then to top it off.

So for car charging, the main thing you'll want to keep in mind is the heat from perhaps leaving it in the car and whatnot.

Here's some battery and charging related information:

Charge the iPhone battery - Apple Support

iPhone Battery and Performance - Apple Support

Batteries - Maximizing Performance - Apple

Hope this helps!

The actual “charger” is built-in to your phone and will protect itself from damage.

That said, and IMO, the safest and most reliable way to charge in ANY car is with a high-quality, vehicular DC-DC power adaptor such as this dual-output, PD-capable model available from Apple:

https://store.apple.com/xc/product/HQ462ZM/A