[Swagman105 (Geoff)]

Asking the question as to whether anyone has had experience using the type of lithium battery as shown in the attached image.
I like to go away caravanning and camping while prospecting for gold. Not only do I need power for camping but also to run a small water pump for my gold sluice. I would love to take my astro gear as well and looking at a versatile and easy to carry battery found these hard case style batteries on Ali Express.
I do have a battery in a battery box in my caravan but it is not practical to remove it to power the gold sluice and I would need to run a long extension lead from the caravan to the telescope site as we generally park under shade. Having a rugged (looking) waterproof battery with a solid carry handle and featuring a number of different outlets cigarette lighter, USB, Anderson etc seems like a much better idea.
Having said that it seems like a good idea does not mean of course that they equate to a good product, so asking around for anyone who may have used one.
They are described on AliExpress as trolling batteries but I have not found any local suppliers for them.