I still continue to use a 105ah Numax leisure battery and prefer the fact that they are obvious silent compared to a generator!!!
I've easily charged up ten packs in a day plus use of a soldering iron, and believe my current one is five years old and still charging up fine.
I'd really consider looking at
https://www.tayna.co.uk/leisure-batteries/
they were really helpful on the phone and have a massive choice depending on your budget.