Build an electric lawn mower, use the dumped power to keep it charged. If it is charging full too often, mow more often
Just find more uses for the extra power for when you have it available and that you don't care about when it's not available.
If you heat in winter with wood, then use an electric chainsaw to cut wood durring times of excess power.
"Would more batteries and another controller be the only answer for lighting. Its what I am using my battery bank for now."
NO, sounds like you need to use the bank for more stuff. Is lighting the only thing you use electric for? What about TV, Computer, Stereo, Frig, fans, washer, deep fryers, ect... If you keep the bank a little below full you won't need the dump load often, then using a heater just when seldom needed would be a fine dumpload for safety even though it's wasting power making heat you don't want since it would rarely be on.