Have to say that I'm very impressed with this compact jump starter that I've had for probably about two years now.
https://www.amazon.co.uk/SUAOKI-2000.../dp/B07F5TLKH3
I know that we've discussed such items a few times on here but I just keep this in the boot and have probably used it twice in the last 8 months following drain from too many short trips over the last year plus the meaty chunk of battery that using the FBH used lately in the cold weather seems to take despite a couple of car battery top ups and maintenance charges from my battery charger every couple of months.
My house parking set up is two spaces one behind the other so if the back car doesn't start up its a major inconvenience if forced to wait for home breakdown services help, especially if I'm in a rush.
As mentioned I've just left it in the boot for the last 8 months without recharging, used it twice, including yesterday after discovering the battery flat, its kicked over and started the engine immediately both times and is still showing 97% charged ready for the next use when required.
Much easier and convenient than the old faff of hunting out jump leads and repositioning cars to accommodate etc etc.
I'd heartily recommend if you're contemplating such a purchase. ( that's not to say that there aren't other similarly decent units available of course)