Any updates on alternator voltage? Amps out? Looking at what I will need for charging caravan(RV) on the road.
If it is 250A then I think they have done a good thing, as they probably only needed a 180-200A to run the car and charge the starter battery.
They have obviously factored in the second battery and other loads on the electrical system like Winch, which should give you at least another 50A spare I reckon if you are not using these other items, to utilise for other purposes in your car (fridge, compressor etc), and charging batteries in your car (and potentially the fridge too).
However you are correct, you still need to balance the amp loads across both car and caravan.
If you are running a second battery in the car, then you may want to consider only charging the caravan battery when the car batteries are full. In my car I have a 50Amp lithium behind a 25A BCDC charger which powers the beer fridge - I can monitor this with the Victron bluetooth shunt. When this battery is full enough, I can switch the power over from inside the car, to then allow the 40A BCDC in the caravan to start drawing power from the alternator. This means in worse case scenarios when all batteries are low, I am not asking the alternator to power 65A worth of battery chargers- when its only rated to 180A.
Also, depending on the batteries in your van, just check to see their charge rate capacity - how many amps per hour of charge can they accept. This may also help determine what Amperage BCDC you use as well.
That being said, even though I have all this switchable setup in my car/van, my suggestion would be to just load up your van with solar panels. I installed 1200W of solar on my caravan now which powers a 330AH LifeP04 battery, feeding off grid air conditioning, induction cooking, 180ltr Bushman compressor fridge, etc etc etc. Needless to say, I no longer connect my caravan to my car, as my solar setup can charge the batteries at around 70Amp.
However, I still have the car setup there just in case.