My two cents worth ... appropriate or not ....

Don't forget the most critical aspect of all solar panels, their design MPP, or Maximum Power Point.

This is specified for all good panels and is the voltage at which the panel achieves the maximum power transfer (to the load).

ie P (watts) = E (volts) x I (amps)

For many 12v panels this is 18v. So a 120watt panel could theoretically output 120 watts at 18 volts and a current of 120/18 = 6.6 amps.

Panels with higher MPP voltages are often selected, when an MPPT (maximum power point tracking) regulator is used. The higher MPP panel raises the volts but lowers the current for the same power (or energy) transfer. e.g a 32 volt 120watt panel would output only 3.75A, reducing energy loss in the solar panel cabling.

For 18 volt panels a simple PWM regulator will do a fair job; but do get one with a sufficient panel VOC (Volts Open Circuit) rating and also ensure that it has a few bells and whistles.

I like a regulator to display at least the following:
Panel and load volts plus amps (power from panel and power to load is also handy), total A/H (since last reset or time etc) generated by the panel and total A/H consumed by the load.
Panel temperature has a considerable effect on panel efficiency.

High temperature (typical in Sunny Oz) considerably de-rates both the panel output (watts) and the panel MPP (volts).

Whilst this is an unfortunate fact of life, it DOES mean that the simple PWM regulator is relatively effective, as the panel volts (18v could easily be 15.6 volts at 50 degrees C) which now more closely matches the battery charge volts of say 14 volts; more or less negating the need for a more expensive MPPT regulator. In cooler climes, early and late in the day etc, a MPPT regulator will likely show a greater efficiency benefit.

Have a look at this simple graph which demonstrates the effect of temperature on a silicon panel MPP.

Any way that should be enough to ensure my (renewed) membership does not evaporate in 12 months time through lack of posting.