I've been running an MXS 5 for the past year on my laid up track car. It runs an odyssey PC680 which is just enough to crank the engine over. It's on trickle and condition charge and I check it once a week - no problems so far with the LED readout.
Tend to crank the engine every couple of months and aside from having old fuel in the lines she starts up after a couple of turns. Certainly no strain during those turns.
I'm debating getting one for my C7 A6 Allroad that's currently sat doing nowt now I'm on lockdown. Don't fancy having to jump that or have to replace the battery!