2025 - jump pack sizing?

People:

Having recently had the pleasure of having my 12V battery die (parked the car, listened to the radio (ACC) for a bit, took a walk, came back and - dead battery) I'm thinking of buying a jump pack to keep in the car. The question is: How much of a "jump" does this car need? I would think not as much as an ICE engine.

Also, I'm eyeing a few of the capacitive jump packs - huge advantage is they seem to have a gigantic temperature range - down to -40, and - where I am - I could run into those temps. Anyone have any experience with them?

Thanks!