12v Aircon for caravan

Do you have any specs on it? Make/model? Website?

At full load it isn't going to last long - assuming you can discharge the Lithium batteries down to 20% (you would want to check that...) you have 160Ah of battery. At full load that's 2 1/2 hrs assuming fully charged, no solar and nothing else (fridge, etc) on.

68A @ 12V is 816W. If your 600W of solar actually produces 600W (doubtful) then you'd be going backwards at 216W/hr or 18A/hr during the daytime. But your 600W solar probably won't actually produce 600W on a hot sunny day - the output goes down as the temps go up (which is when you want to use your A/C). So you'll go backwards faster.

His solar system is rated at 1580W (395 * 4) or 131A but on a good day he's seeing 96A - or about 75% of the rated power. That would give you about 450W or 37A from your 600W of solar. So at full A/C speed and solar you're going backwards at 31A/hr - the batteries would be flat in 5hrs.

It may be that after a time the A/C ramps down - I'm not sure how much power you need to keep a caravan cool - and so it would run for longer.

My concern for you is that you will flatten the batteries while it's running rather than charge them up. My guess is that it might work for overnight for a few hours when you want a little bit of cooling but don't want to run the generator.

There is NO 12V air conditioner that will come even close to cooling a caravan. Anybody that tells you there is lying outright.
The 12V/24V air conditioners that are available use the BD80F Secop compressor. They are at best only suitable for a truck sleeper cab, and that is what they are made for. No different to the evaporative coolers, only suitable for sleeper cabs.
The other issue is the 12/24V air conditioners are not at all efficient and are dinosaur technology.
The Mitsubishi Heavy Industries Avanti Series 2kW is 7 star efficient, only suitable for small caravans. 2.5kW up to 17' and 3.5kW up to 21' - as the air conditioners go up in size the star rating efficiency drops slightly.
Have a lot of these running on inverters in RV's, but all with lithium batteries in *correctly* set-up solar systems with excellent equipment, not the usual trash equipment you see people talking about here. If you are prepared to spend the money and do the job properly, life is a dream. On properties using inverter air conditioners on inverters, they have adequate capacity (read 'large')lead acid batteries on 48V systems. You a'int going to do air conditioning in an RV with LA/AGM.

Edit: Quote - "This 12V unit is more powerful than most 240V units and draws less power than running a 240V through an inverter. " That is blatent lies. Nothing compares to inverter units and their 7 star rating.
Would never fit 395W solar panels to any RV. Doubt they would survive long. Shade tolerant - be interesting to know the brand, because don't believe it.

You could by a couple of these they might help to take the edge off a little in a dry region, don't use much power. https://transcool.info/product/transcool-ec3-plus-portable-evaporative-air-conditioner-copy/

I have 990 watts of thin film solar on my caravan roof with 400AH of lithium batteries and a 1.4KVA inverter charger. On the back is a very small Toshiba split system aircon. Run it flat out and it can easily draw 90 amps from the batteries while it cools the van down.

But put it on "Quiet" setting and choose a temperature of maybe 25 degrees on a hot day and it settles down to 20-25 amps. Run in conjunction with a Sirocco fan, it's quite comfortable. You can't hear it inside the van and it's silent outside a couple of metres away. During the day, the solar will run the aircon as well as charging the batteries.

I looked at a number of 12 volt system for truck cabs. But they are undersized, expensive, inefficient and use old technology.

Keith

Maybe something like this Close Comfort