What happens if you put in more Solar wattage than a Delta Max
Connect them in parallel. Done right, this will give you the full solar input power for 6-8h on sunny days. The River batteries are usually already full after ~3h. So you can pull off something like a freezer in pure solar power without using the battery for 8h, maybe 10 or 12h per day. The battery will only be used during the night.