Just found this interesting writeup on charging system. Doubtful if purchased due to cost but I learned a few things. Too pricey to protect just one battery.
Should be one time purchase since brushes are separate.

https://www.smartregulator.co.nz/uploads/102446/files/Voltage_Regulator_User_Manual__2013_Version_12.pdf

Probably really good addition for multi-bank batteries, RV, Boats, etc