Sorry for the delay in responding back. I did not get a notification like I usually do.
Maybe something along these lines will work? https://www.amazon.com/VOLTCUBE-Inve...s%2C154&sr=8-1

you have a solar panel on your trailer? get a small inverter, maybe 200W 'peak', and use that to charge the laptop during the day.

Hi John,
Assuming we don't experience a variety of apocalyptic events in the next 6 months, I'd like to explore some dark sky sites in the Southwest. I'll be off the grid of course. I send commands to my 20 via a laptop. Could you suggest how I might charge up my laptop while off the grid? I'm guessing you might say: 'buy a Honda EU2200i'. Or something along those lines. I built a box small box on my Obsession to house an 18 amp hour battery. It runs the scope pretty good for 3 nights. I can't actually recall 3 good nights back to back where I ran the scope. But that's another issue. Thanks.
Dick