I've got the Milwaukee M12 inflator, handles 65 PSI just fine but I don't have any 80 PSI experience. I did inflate a gentleman's spare that was reading 0 PSI when I hooked up to 65 PSI with just one rest (hose was starting to get hot so we mounted the tire while we waited, by the time we were done jacking the corner higher and putting on the lug nuts it was cool enough I was comfortable enough to go from 55 to 65). I'm using 6 Ah batteries I bought off Amazon for $40 for 2. It's not the cheapest solution but it's probably the smallest that can handle RV type pressures, combined with the ease of use vs corded units I thought it was well worth the investment.