We have a ChargeMaster 24/30-3 & a ChargeMaster 24/100-3. The 30 amp charger is the newer of the two. Mastervolt was introducing a 40 amp version that would charge both the 24 & 12 volt batteries (engine starting and house) but it was not yet available when we had to replace the Xantrex that died and toasted our 12 house batteries.