Normatec Battery Charging and Care

Does anyone know the best way to ensure long battery life for the Normatec boots compression unit? Should I leave it charging when not in use (i.e. for 23 hrs a day, every day)? Alternatively, is it like phone batteries where you should keep it charged to within a certain range (no idea if that advise still holds true)?

I couldn’t find anything related in the search … apologies in advance if duplicated.