I’m going to stir a hornets nest here!

I have a nagging feeling that all this fuss about what battery to use as a leisure battery is unnecessary. Years ago before leisure batteries were invented I had a lot of caravans and as they had these new fangled electric bulbs which were beginning to replace gas lamps I thought I would be very clever and rig the caravan with a battery to run them. I found a spare pin on the 7 pin plug on the car, wired it to the car 12v and fitted a scrap yard battery in the caravan. I connected it to the caravan lights and to the plug pin with 12v and the lights worked off the caravan battery which was charged from the car when the engine was running. When I would sell the caravan, the buyers would be very impressed that the caravan had its own battery.
Nowadays though I have 200w of solar panel and a 2kw pure sine wave inverter and 200AH of lithium batteries I can skip the site electric and run a 240v kettle and an induction hob. You must have a proper pure sine wave inverter if you want to run any device with a microprocessor in it, such as an induction hob. But in the end, so what? I can perfectly well boil the kettle on the gas and cook the sausages there as well. Of course I also have a refillable gas bottle and a 4 burner cooker with grill and oven.
I have all this ‘stuff’ not because it is necessary . It isn’t. I am a retired electronics engineer and a retired gas wallah (GSR registered people are not engineers, just labourers) so I tend to just do these things because otherwise I would be bored. I read of people spending silly amounts of money on having this stuff installed and it’s all unnecessary really. It’s only worthwhile if you can fit it yourself. All campers now come with leisure batteries whether or not they have solar panels as well. If your leisure battery goes flat, just go to a scrap yard and get a replacement one of the same size with the lugs correctly orientated. When the lights go dim, get another one. If your tv goes dim, chuck it in the bin and get a life. If you are so bored with where you have stopped for the night that you are reduced to watching the tv, get in the drivers seat and go somewhere interesting.
The bottom line regarding batteries is that the only benefit of a lithium battery is that it will withstand high current drains for longer than a lead one, but that will only enable you to watch the tv for half an hour longer than a lead battery would. And lithium batteries vary enormously in quality - if you are going to get one or two, do some research before choosing. And if you get one from Temu make sure you chuck away the rubbish aluminium cables that come with it and fit heavy, thick pure copper cables . . . . or better still, don’t get one from Temu