To determine how many amp-hours a 12v panel provides take it’s rating in watts x .3. So a 100W panel produce about 30 amp hours per day. Panel makers list their MAXIMUM wattage the panel can produce with optimal conditions and that is when the panel is directly facing the sun in both altitude and azimuth.
To get very accurate look at the back of the solar panel or consult specs and find the maximum rated power of the panel in watts. Look also for the maximum power voltage, Vmp, which is in volts. Calculate the current in amps by dividing power in watts by the voltage in volts. Mine are 100W panels with optimal Vmp of 18.9V which for me is 5.29 amps. Even in sunny Florida I need four panels to guarantee my three 120AH battery array is fully charge if I have the telescope running every day of the week simply because while these panels are at tilted at the correct altitude they are fixed due south. In the summer two panels are enough but the winter is different, and we have much clearer skies in the winter here. Most panels max out at about 230W so I think one highly efficient panel, even tracking the sun might be tough to keep the charge full.
Keep in mind your batteries will last longer the lower you drain them. A battery drained to 40% before charging will last a much shorter time then a battery only discharged 10%. When doing this, buying one or two more batteries can make them all last longer.