Sundanzer Solar-Powered Freezer - 8.1 Cubic Ft

Installed this unit about 2 years ago in southern Michigan so it's been through two winters now. My installation is powered by 300 watts of solar panels, which is more than needed but I don't have a good sunny spot in the back yard. Unit is operated at 24 volts using four 6-volt golf cart batteries in series that were purchased from Sams Club. A cheap charge controller was bought on eBay. This combination works fine but the freezer does not keep things as cold as a normal freezer. It stays around 15 degrees F, which I monitor with one of those cheap indoor/outdoor wireless temperature gauges from ABC Warehouse. This temperature is measured near the top of the freezer so should be about the warmest spot. I tried using 130 watts of solar panels and it did not do the trick - maybe if I cut a tree or two and adjusted the panel vertical angle seasonally it would work with the 130 watts?11/29/12 UpdateRecently the freezer's control unit died and freezer would not work at all. I contacted Sundanzer (915-821-0042) and spoke with "Billy". He was very helpful and, even thought the freezer is out of warranty, he shipped me a replacement controller at no cost. Replacement was easy and the freezer is now functional again. I did learn that Sundanzer has gone to a different manufacturer for the controller (and compressor?). The controller in my unit was made by ACC in Italy. I'm not sure what kind of service I will receive in the future as it is my understanding that Sundanzer no longer uses this manufacturer. The controller Billy sent me was one of only six they had in stock and they were not able to test it before sending it do me. Billy attempted to test it with the only compressor they had in stock that was compatible with the ACC controller, and none of the six controllers they had in stock would work with that compressor. Thus it would appear that the only compatible compressor Sundanzer had in stock was defective. I also asked Billy if there was some way to make my freezer operate at a lower temperature and he responded that he would also send me the "ice cream thermostat" for my freezer. Again, replacement was a snap but it did not seem to make much of a difference in the freezer's temperature. I concluded that I probably did not have enough solar panels to keep my 24 volt battery fully charged and added another 124 watts of solar panels, making a total of 424 watts in panel output. The freezer now maintains a temperature consistently around 2 degrees F toward the top of the unit and a degree or two lower at the bottom. [email protected]/6/2015 UpdateUnit is still working well.12/31/209 UpdateCompressor controller died again about 2 years ago and I scrapped the entire unit.