Solar/Fridge/Batt. Stats post Fraser Trip

People,
Thought you may be interested in the performance of my solar setup over the course of a recent week long trip to Fraser Island.

My vehicle is a Cruiser Ute, with a tri-battery setup. Normal start battery, with an ARB smart solenoid to a pair of Exide 75a/h deep cycle batteries wired in parallel (battery cable is all 3 B&S, equal to 23mm2 cross sectional area).

From this I power an Explorer 78L fridge/freezer (sits in tray), versa-lite fluro and a Narva 55w work light in the tray.

Solar power is via a 120w Kyocera mounted on the roof, with a Lyncom true 3-stage charging regulator. I currently have 1.8mm2 cable wiring the solar together and according to most references, this is way to small to avoid significant voltage drops.

I charged the aux. batteries with an 8 amp three stage charger before leaving. Over the course of the week I saw no less than 12.3v under load conditions with the solar removed, and no more than 14.1v connected. Peak amperage output from the panel was 5.6 amps (only doing spot checks so may have been higher).

Upon my return home I checked the aux. batteries with a hydrometer and all cells were an even 1260. Could say I'm a very happy camper!

Some other relevant points include
-I kept the fridge shaded at all times while in the tray
-Tech. gurus say that solar panels laid flat should be de-rated by about 20%. The 5.6 amps peak that I saw is almost exactly 80% of the peak power of the panel.
-The fridge is rated to use about 36 amp hours per day
-12v fluros appear to draw bugger all
-the 55w work light appeared to use significant amounts of power when left on for long periods eg. while filleting (noticed the voltage display drop by 0.1-0.2v).
-I believe that the benefits of the car running during the day would be almost negated by the stereo and the night-time running of my spotlights (460 watts total).

Hope some of this may help others who are weighing up a solar setup or trying to accurately size one.

Cheers
Craig