FBJR, in my opinion, it worked great.
Every am (about 7:30) while the water was cooking for coffee, I would check the bank with my meter and log the result. Also was "testing" the frig at the same time.
The solar panel was turned a minimum of 3 times a day to maximize the output by me or my neighbors. What was cool, people just walking by would turn it without being asked!
Using the hi tech pre-frozen water bottle in the freezer test, I would adjust the thermostat down daily about a point everyday starting from the highest 5 (0 to 5 dial).
Once the bottle showed signs of melting, the thermostat was turned back up a 1/2 a point. Ended up settling at final setting of around 2.5 on the dial.
Here are my obsessive results:
Day- outside temp- weather- frig setting- bank volts- volt change
Monday........82 sunny....5....12.70.....full charge
Tuesday.......84 sunny.....4....12.62...-.08 volt
Wednesday...86 sunny....3....12.56....-.06 volt
Thursday......84 sunny....2....12.48....-.08 volt
Friday..........79 cloudy..2.5...12.50...+.02 volt
Saturday......77 sunny...2.5...12.42... -.08 volt
Keep in mind the bank voltage reading was in the am, so it shows draw/usage from the day before.
The consistent -.08 drop threw me off at first, but kinda makes sense now. The outside temp was going up but the frig was being turned down so they equalized.
It also looks like the cheapy solar can not only keep up with extremely frugal usage but actually charge (only .02v) the bank.
Seems that if it was in a sunny area, the bank would be good for at least a couple of weeks before dropping to 12v.
If I was to drive into town once a week for supplies,being topped off by alternator, swagging they would last "indefinitely".
With no sun at all,not running the truck, 9 days???