This lines up with my personal experiences. I have personally used a car battery to keep a big gaming laptop charged for an entire weekend, and it was being used (if not under heavy load) for about 10 hours a day.
Those big batteries are extremely heavy and very expensive, but we're talking about people who want broadband internet service on their boat. Money is not a concern here.
I'm sure Starlink has different power modes for these things, but the average consumer is likely far more interested in optimizing for connection speed and latency.
I also just mounted 600W of solar on the roof.
The power needs of Starlink is a tad annoying, but certainly not a deal breaker for anyone living in a vehicle that actually needs internet anywhere on the planet.
I have plenty of solar and batteries to run starlink 24/7.
Even if you don’t have a lot of amp hours, starlink allows you to set a sleep schedule where it would use way less power.
But ditching the starlink router and converting to run off 12v isn’t that hard
With sat, the power needs are mostly a physics problem. You can't generate a 30 watt signal unless you draw 30 watts from somewhere. It's just the nature of the beast. It's also why lower-power sat systems like Iridium or Apple's thing have relatively limited functionality.
You’d have a lithium battery and an additional power source, like solar or generator, to top that battery off.
Edit: a vanlifer showed up and informed me that Lithium conversions are a thing. Turns out you can have your Lithium and eat it too. Cool stuff.
Now consider that the real power draw is probably well below the supply's rating, so it's actually 40ish watts on a 1200Wh battery. Now we're pushing 30 hours.
Now consider the real sickos of the "rich boat owner" class. These people have large engines in their boats, and those engines have alternators. All cars have those, too. That's a power source already integrated into the boat itself. A simple DC step-up regulator wired into the boat's existing electrical system is a much more elegant solution than a second set of batteries and a second power source to charge those batteries.
For reference 60w is similiar power draw to a Dometic fridge or a laptop.
Also adding a huge heavy battery to a boat is a non-negligible consideration in a lot of cases.
My fridge pulls 50W when cycling the compressor and my current 5G modem/router pulls 15W. Indoor lights draw over 20W alone on full tilt.
I have 200W of solar on my truck and my alternator does 400W and realistically I charge at around 550W on a good day so 40W is a drop in the bucket.
RVs can have much beefier systems than my setup. I don’t full time or anything — just long time camper for 10 years before van life was a thing, so my setup is relatively low capacity.