David,
Over the past 3 years, my camper has been on my truck 4-6 months out of the year (between May-October). 95% of its use has been in the Intermountain West. For example, this summer I was in WY, ID, and MT July-October, with all of the usual weather and conditions one would expect, from hot and sunny (100F+) to snowy, cloudy and cold (low of 8F).
I have the usual appliances in my 2016 Fleet with 2 AGM 12V batteries: furnace, 2-way 85L fridge, Fantastic fan, LED lights, plus I charge a phone, tablet and gps. I tend to be very conservative when solar conditions are not ideal (e.g., thermostat at 45 degrees when snowing or raining or cloudy for multiple days). Under average conditions and use, my two panels and the GoPower controller have no trouble maintaining the batteries and running through the default charging profile (albeit with the usual caveats about inadequate charging profile discussed at length on this forum). When it's consistently cloudy/rainy/snowy for multiple days then the battery SOC slowly declines because panels can't generate enough juice to trigger bulk charging. Still, I infer from closely watching my controller monitor voltage and referencing battery SOC charts, that I rarely discharge my batteries below 60%, and usually not below 80%, but I don't really know because I don't have a true SOC battery monitor.
When on my truck, the camper is outside; when not on my truck, it's stored under cover in our carport. The panels appear to be in good condition, albeit with some slight cloudiness. I need to contact GoPower to see if they recommend a particular polish or cleaner. I have driven through some low-hanging tree branches and tested the height of a public parking garage ceiling and they don't have any noticeable scratches.
In retrospect, I wish that the panels weren't attached directly to the roof and wouldn't make that choice again, and would probably go with one of the lightweight mounting solutions discussed here. I dread having to replace these one day. I wouldn't hesitate to buy these particular panels again, because I really like the low profile, weight, toughness and performance (so far). You might want to contact Martyn Davies at Adventure Trailers in Prescott to get his first-hand experience with the longevity and performance of these particular panels since they sell and have installed many of them.
Let me know if I've adequately answered your questions. Good luck on your decision.
Cheers,
Jeff
