I am working on a design for my class A RV that will get me close to 4kw. Here's my plan:
I want 60 cell panels so that I don't need a solar controller. These are very common and are typically .5$ per watt, or even less when used.
Higher efficiency modules probably do me no good, because it seems that the module efficiency simply raises the Vmp, which means I gain nothing from higher efficiency cells because the cell is tied to the LiFePo4 battery voltage.
I plan on putting 6 fixed panels on slides, with 6 flexible panels of similar size and wattage below them mounted to the roof. I'll keep some of the existing 100w panels that I have on the roof for tighter spots for an additional 500w. This would be about 2300w when driving and about 4kw when parked and slides extended.
The idea with the flexible panels is less weight. The big ones are 40lb, plus slides and motors, puts maybe 400lb on the roof, which weighs heavily on my conscience. I'll remove maybe 150lb of air conditioning up there, but if I'm honest the 2 interior head units of the mini split will be up high too.
I found a supplier on aibaba that will sell me 60 cell sunpower panels. After panicking over the tariff issue which this thread raised, I am concluding that these are an exception to the tariff because the cells are USA sunpower cells. It seems I will be paying 300 per panel plus $1500 for sea shipping. Not cheap, but then not 40lb.
If you're determined to use large panels on RV's (for $/Watt reasons), install a few cross strips on the back to form an open lattice to support the glass & reduce unsupported span.
I have not found 30 cell fixed panels, so I'll want to run additional trusses under the fixed panels on the slides.
I figure the flexible ones will be rather protected while I am driving, and they won't be handled to be deployed. In theory, the sunpower cells are more durable than what Will has endured. I will want to close the slides when there are storms, which also covers the flexibles so there really should not be hail or rain whacking the ETFE.
Anyone have additional thoughts for me?