Hard for me to guess and there are a lot of variables. I haven't personally used this AC unit in the wild yet. It's sitting in my garage along with a bunch of other parts waiting for the new van to be delivered.
I exchanged messages with a guy who has one on a ford transit and he says the compressor runs less than 50% of the time on 95f sunny days and pulls about 1300 watts when running. That sounds pretty optimistic to me, but as long as it's not running 80% or more, that should give me a decent buffer. I'm optimistic it will be enough to make it through the night with reasonable reserve, but I won't be adding more battery if it doesn't.
