I bought an Autowit, it wasn't cheap. $130. Super capacitor seems to be the way to go for cold climates, which I know doesn't apply to you 😉. Lead acid sucks, and lithium ion needs to be kept "warm" (above freezing): and in -30C: doesn't seem to work more than a jump (if you're lucky)
We get just sub zero in deep winter but somethings are just hard to start yeah you wouldn't want to leave your lithium jump starter out in the rig in the cold expecting it to save you
