You nailed it! Those numbers will keep your battery charged without overcharging it. A fully-charged battery will need about 13.5-14.5 volts to keep it charged. If you want to really monitor the performance of the charging system get a hydrometer, the glass vial type with a float inside, and monitor the concentration of the battery acid. It should be somewhere in the range of 1.250-1.265 for all the cells, with a variation of no more than 10 points (.010) between cells. A completely discharged cell would have a specific gravity of 1.000 (plain water) and a fully-charged cell will be around 1.260, plus or minus a little which is the strength of the acid when the battery was new. A noticeable difference from one cell to another indicates the reactive material on the battery plates is sloughing off and accumulating at the bottom of the cell where it cannot enter into the charge/discharge reaction on the low-gravity cells.
Jerry
