Charging and maintaining charge on house batts

You will have to tell us if your average consumption is less than 8 amps.

And, also that the 8 amp charger is a smart one and will not burn up the batteries by overcharging them.

Even if you are OK per both above, they are short term solutions IMO. Either get the inverter/charger fixed or replaced or go with a smart converter (much less $$) if you don't need the inverter function.

BTW, how did you damage the inverter to the point that it needs to be replaced?