The stock converter is a 3 way converter with bulk, float and quick charge cycles, perfectly safe to leave plugged in 24/7 which I did this winter to keep the battery warm. The solar is a good compliment and is more gentler on it's charging cycle, so between the 2 you do not need anything else. I just checked my water in the battery, all 6 cells are still full. This tells me the converter is not boiling out the acid as some can do.
never in doubt, often wrong