I have started reading about RV solar systems. One of the bits I have picked up (from a variety of sources--Solar Bob included) is that matching the charge voltage of the controller to the manufacturer's spec is important in order to bring the batteries up to full charge. Do you know what the charge voltage of your 20 amp controller is--and do you know what the manufacturer's spec is for your planned battery bank? It appears that the smaller controllers are sometimes set at a voltage that is too low.
OMG, the Silver Streak is Sold!
2006 SMB EB45ish.
5.4L, QuadVan 4x4
Ready to Rumble!