brunnhilde wants some sun

 

I have been pondering the difficult challenges of installing photovoltaic panels onto Brunnhilde but the roof area small and all have been utilized except the curve front portion. I am not interested in the flexible kind of panels due to their relative poor reliability as well as the difficulties of securing them from aerodynamic lift, short of drilling holes into the fiberglass high top. I know people have installed them with high strength tapes. It is not something I would do as the bond is only as strong as the weakest point, and with the James Cook top it is the paint finish.

For photovoltaic power, the longer you waited the better the technology and cost, at least up until recently. I finally feel that it is about time that I give the matter another look, with an open mind. Having Brunnhilde this long I am at ease to know what are important. While the big Heki power skylight was a killer selling feature, in reality it is one of the worst thing. Each hot day I look up inside and it irks me of how much solar gain it introduces when not open at least a crack. The unreliable wireless-only control is not to be trusted, as when it fails you have a major PITA task ahead of you to close it manually before you can leave the camping site.

I am now entertaining removing the big Heki all together and use the roof top real estate for solar panels. Yes. I know for most the romantic notion of stargazing. It is rarely in our use cases. Think different is my motto, especially able to think out of the box.

So the question is how much solar can be installed? The most obvious choice is the most common 100W rigid panel. Even before checking the dimensions, one can see the benefits of mounting them where the big Heki is. It is the most aerodynamic location as well as secure as there is already a deflector built into the roof. By installing two rigid panels side by side behind it it improves the air stream and even help it over the air conditioner.

Additionally, the PV panels will reduce solar gain of the roof forming shaded area. Think why the classic Safari Land Rovers have the double roof.

would two of these fit side by side?

I did a quick check by eyeballing the lengthwise dimension between the front air deflector and the Coleman AC and there is more than 37 inches of space, so two of these 100W rigid panels should fit. I have not research the current offering of common panels that claims to be 100W. The honest wattage and price is not as important as find ones that maximize the wattage produced given the dimensional constraints.

My goals are not unrealistic. No wishful thought of powering air conditioner or using microwave oven, or even coffee maker. Just to keep the house bank charge and two of these panels should be more then adequate, as the biggest power consumers are the Dometic refrigerator and the diesel furnace.

this is an illustration of how two PV panels fit side by side, and the improved airflow on the roof

This is all very preliminary brainstorming. More to come.

Update:

there is about a 44" x 44" square real estate if I were to forego the big Heki skylight and use it for 2 solar panels

I climbed up on a ladder to get a rough dimension of the free area. It is about 44"x44" nearly perfect square. Clearly two of these 36.4" x 26.8" panels may not fit that well, thought feasible. For similar area and wattage but longer and narrower, around 41" long by 21 inch wide, that should be perfect fit with two side by side lengthwise.