Had trouble with my 31 year old Sentry 60 amp charger last year. My repair guys talked me into sending to Sentry for repair. Cost about $400 and has worked perfectly since. I have 2 banks of 3 group 31 12 volt batteries instead of 2 8-Ds. Both function as start batteries with one handling house. I have a combiner switch also. Use the generator whenever we are away from shore power too. Not sure I want to install inverter with the requirements to do so properly. As far as new multi stage chargers I have heard both good and bad. For now I am satisfied with my old school Sentry and know the factory will still repair. Their website discusses repair of older chargers. Lots of different ways to go about this and just depends on your preference. I would think with the 8 Ds you would want at least 60 amps.