Hello all - I'm hoping to build out a battery box for camping, and I'm stuck on selecting a charger.

My plan is to pick up a 12V 165A LFP, pair it with a DC-DC charger, and charge it up as quickly as possible to allow for multiday trips with limited solar. Pulling more power from the alternator would be ideal, and pulling meaningful power at idle would be a plus.

I've seen recommendations for a charger around 50A (e.g. Victron Orion XS), but I'm struggling to characterize the performance I'd see at idle. Can anyone weigh in on the following?

- The 2017 JK alternator looks to be rated at 160A. I'm assuming a 50 or 60A charger would do fine while driving?
- For a stock JK, what current can a DC-DC charger pull at idle with accessories all on or all off? I'd bet that there's significant headroom, but how to find the limit?
- Do DC-DC chargers step down gracefully from their rated output, e.g. if a 50A charger is seeing 30A at idle, will it drop the output or cut off entirely?

Thanks for any help you can provide!