Solar Power or Not

Brue, having plenty of solar and a clever regulator can allow spare sun to be diverted to the fridge and via a D+ signal (like that sent by the alternator when the engine is running) it can be told to run from 12v (while sun stocks last) thus saving on any EHU or gas costs.

additionally, an inverter can run a mains hair drier and mains Ebike charger. 
everything else is already 12v....

My origonal challenge was about a replacement battery and from there I explored lithium batteries but your normal 240v charger in the caravan does not put out enough volts to charge lithium batteries (14.6v . for lead acid its 14.4v) hence the reason for saying a complete overhaul of the charging system may be needed . My caravan is 3 years old and the solar charge system uses a PWM charge controler and not a MPPT controller which is a lot more efficient and I wonder if the caravan built in monitoring system would be of any use after an upgrade.

I do however think that this is really not worthwhile given the cost of around 2000 pounds (could be more). I am still exploring options but thought it was a good subject to guage the feelings of members at this time of rising energy prices and give me and others a guide as to where the hobby may be going.

  I would still like to be off grid at least part of the time while caravaning

Of the mentioned £2000, it is the change out to Lithium that dominates that huge cost, not simply the move into solar.

" I would still like to be off grid at least part of the time while caravaning"

There is no reason why you can't, and even if started from scratch a fraction of that investment, but in your case you already have something. 

In our case, with just an 85 Watt freestanding panel, we can, and generally do, go from a mid April Easter through till October, on occasion being out for 28 days, totally automatously from an EHU.

It does come with using gas, butane the cheaper if using exchanges. Though the fridge functions, we have hot water, we can "cook" food, run a bit of heating if needed, and watch the little of TV we wish to.

Whilst changing to a quality MPPT should gain a bit more yield, and at the more useful times when the solar energy is low, it in itself is not IMO a "lot more efficient", just more, and better if designed from the ground up as a MPPT system not just via a change out of the controller.

Have you tried your system in the sunnier months?

We had power cuts at the end of November last year and  we retired to the caravan for warmth and TV . We have stayed here ( in the midle of nowhere) for 30 odd years so the kitchen has a gas hob( Which was intensional) but 6 days without power was getting rather annoying by the end . We used the caravan as a warm haven that had light and tv. 2 nights is all it lasted and the result was a broken battery and the need to buy a generator for the house. I did not think that the TV would be a heavy user of the battery power so it lasted around 14 hours over 2 nights. The solar panel did not help much as the weather was rather grey and daylight rather short aswell.

     This is where this thread has its origons .

https://www.roadpro.co.uk/

This is where I have taken my research to at the moment he seems approachable and willing to help

I think that there’s too much talk about money and not enough about enjoyment. For some, the regimentation of well equipped sites provides the safety and convenience they seek. For us, less is more. We’d really like to find those isolated, off the beaten track places popular which leisure vehicle marketing teams use for photoshoots, doubtless accessed via a traffic free road through unspoilt countryside.

If less appeals to you to, be prepared not to save money. What you save on site fees will be spent on refillable gas bottles, solar panels, extra toilet chemicals and the odd trip into a town with enough internet connectivity to download your emails. We are equipped with a few more extras too - a 12V charger for the Dyson, ditto my husband’s electric razor, an inverter for the laptop, car chargers for pads and cameras. Then there’s catalytic hair straighteners and a backup battery, charged via modified car electrics when driving without the van.

Are those extra costs worth it? I suppose that it all depends on whether back to nature is more appealing than regularly mown grass.