Words of Wisdom: “It's not a lost cause.. we just seem to be at that frustrating cusp where it's technically possible with current technology, just not easy or cheap.” – thatswhatsup1)
Running AC on [an inverter] is rich man's game – HaldorEE2)
TL;DR - It is technically possible, but very expensive and complex. Be prepared to spend at least $5,000, and probably closer to $10,000.
More expensive than the A/C system itself is everything you'll need to power it. A/C takes a huge amount of electricity; to operate successfully off grid you'll want at least 8-12KwHr of lithium batteries, 800-1200w of solar, and the required massive charge controllers to run it all. If you want to run the A/C overnight, be prepared to double that battery bank size.
If you are reading this you probably haven't done the math. Prepare for some unpleasant news, because at this point you may not be familiar with:
And that's just considering running the unit in optimum solar conditions in the daytime. Running A/C at night requires a magnitude increase in battery bank, and then even more panels that are capable of both recharging the batteries while running the A/C during the hotter parts of the day. See this build thread of someone who does.
And it's still not going to give great results; it might be okay for taking the edge off on a very hot day (bringing the inside of the van down to 80f while the exterior temperatures are over 95f), but you're not going to be able to keep the van at 68 degrees on a hot day just off of solar.
Especially because (rather paradoxically) running A/C off of solar requires that you park your van in the sun; which means the inside of the van will get MUCH hotter than it would if you simply parked in the shade. This puts you in a weird catch-22 where you can't run the A/C without parking in the sun, but parking in the sun means you have to run the A/C much harder than your solar can sometimes keep up with.
This is very practical, and it's how RVs have been doing it for many years. The A/C systems run natively on 120v AC(Alternating Current) and are getting power from a generator or shore power.
120v AC units are vastly more common, and much cheaper than the 12v or 24v DC units. These are usually roof-mounted, smaller ones can be had for as little as $500 and are very common in the rest of the R/V world. If you have a a big enough inverter, it's possible to run them off of a house battery bank as well (although you'll suffer some efficiency losses).
See this article for a good overview on what may be needed.
The things you see on social media are either:
There is an extremely small subset of people who have successfully installed A/C in their own van, and been able to use it off-grid for extended periods of time. They are people with an in-depth understanding of the issues and the money and space to make it happen. It does not stand to reason that the average person with average resources and commitment will make the trip from idea to implementation.
There is a reason that most people snowbird (follow good weather) and use roof vents to control humidity and temperature.
Don't say we didn't warn you, but here's some links to people who have done it successfully. Start with this post by trebor then check out posts by people who have done it:
Also see
AC Units that can operate directly on DC current off of your house batteries give some efficiency gains as you don't need to run them through an inverter, but they are very expensive. Higher voltage systems allow you to use much thinner cables for power, which can be a significant cost savings over longer runs.
All-in-one roof units offer a much simpler installation and are usually around $2,500; Dometic has their RTX 2000 unit as a good start for most vans. The relative ease of install comes at the expense of taking up quite a bit of roof space (and consequently reducing your available space for solar panels). They're heavy as well, and generally you'll need to reinforce the roof to hold the weight.
Split units separate the evaporator/condenser/compressor into separate parts which have to be plumbed together. This can offer a lot more flexibility in terms of where to mount stuff, but also makes the installation much more complex. Cruis-n-comfort and UnderMountAC are the two most common split options, and will generally run $4,000 for the units themselves.
Beginning in about 2023, cheap Chinese 12v mini-split systems have started to come down to almost acceptable prices ($1k in the USA, or less if you can wait the 1-2 months for shipping from China). Reports on them have been mixed; similar to the Chinese knock-off diesel heaters they come with almost no instructions and often missing a few minor parts (most users report some fittings or couplings being missing, or needing to crimp their own lines). Warranty and installation support is non-existent, but if you can fiddle your way through the psudo-DIY installation some people have reported positive results.