An occasional charge to 100% is recommended to allow the BMS to balance the individual cells & keep them in tip-top nick. But once I've done that, and let the car sit there for an hour maybe to give it time to do it's thing, I'll run the heating with window open on my drive for a couple of hours to knock it down to 80%, where I'm happy to leave it for days during lockdown. Discovered I can't lock my Ioniq from the outside leaving 2nd key inside it (and window open to let heat out, and me in if necc!!!) to keep electrics on while I do this, so I have to block the car in with wife's C1 to stop anyone nicking it!