Increasing size of Lithium batteries

[Twincam Escort]

I have a 2021 Wildax with the 'volt pack' option that I bought 2nd hand.
This was/is an expensive upgrade that does away with gas completely and in theory allows off grid camping.
Amongst other things it comes with a 3kw inverter, 200w solar (I think), smart alternator and 2 X 100Ah lithium batteries.
Problem is that boiling one kettle takes approx 10% of my stored capacity! Although driving around charges them up quite quickly, the solar is weather dependant and slow.
Each battery is approx 315mm (L) x 160mm (W) x 220mm (H). I have looked at the current LiFePo batteries and they seem to be able to pack a lot more amps in the same size. Are these new ones different chemistry to mine?
Could I just replace these with bigger storage ones?
Would it cause me any issues with the voltronic meter?

 

[StillGoing]

A 3kW inverter can draw up to 290A from a 12V battery. That is way more than your leisure batteries can provide. I hope your batteries are protected with suitable size fuses so the inverter can’t exceed the specifications of your batteries.

 

[ChrisL]

I would double the amount of solar you have if you have space as well as increasing your battery bank.