I have half a dozen battery maintainers, two shoe box sized 6-10 amp 6 volt-12 volt chargers that are 30+ years old and one 4 level charger including 100 amp boost for the heavy work. Seldom use the big boy but it's nice to know it's there if needed. The higher charge rate on your charger will not hurt for short periods, just don't forget it's on there. My large charger instructions actually say if the battery is almost completely discharged put it on 100 amp boost for 2 minutes before reducing to a lower charging rate to bring it the rest of the way up.
