800AH, 12v or 24v?

[wpns]

using a dehumidifier to have some small source of water where it's humid

Check your power budget, this may cost a KWHR/gallon?

 

[AmpD]

The main thing I’ve read that a stepdown introduces some inefficiency losses in the conversion to 12v. Depending on the equipment and frequency of use it might be a little or a lot.

I have a 120v 4.4CuFt fridge. It is rated at 100w. Most of the time it is pulling 10-40w. A small fridge is pretty doable on solar imo.

Some of the rv DC units are more efficient and have features that make traveling more convenient like how inclines influence operation, securing latches, or options for DC/AC/propane.

Been sorting out a lot of it myself for the past 2 years. Originally thought I needed 5kw surge capacity and 1600ah of bank. Thought I might need 48v. Then I looked at 24v with equipment able to upgrade to 48v later on. Now I’m thinking 12v and 2kw-3kw of surge ability. Likely going with a victron 12/2000 multiplus and a 12/1200 phoenix to cover that.

Remember panel wattage must be greater than your usage to charge the bank. If your only using Air conditioning during the day and have ample solar input then you might not need a 3000ah bank. But if you run it 24/7 you will have to account for the dark period. It will also depend on how much room you have for panels.

Aside from wires and fuses your chosen voltage will also affect your scc options. For example a victron 150/45 can run 650w of panels in 12v, 1300w in 24v, and 2600w in 48v.

 

[740GLE]

For me it was double the current capacity of the SCC that made sticking with 12v not worth it.

I’d much rather have one 20a SCC vs a 40a SCC for the same panel array.

 

[littleharbor2]

Pretty much anything that generates a lot of heat needs to run on dinosaur juice.

Or dinosaur farts, (propane).
Also, for the OP, The power trailer sounds like a good option being that you could park your van in the shade and still suck up PV energy.