I have my portable 150w solar blanket out in the sun and my van is sort of in the shade as its quite hot here.
So that means my roof top panel is not collecting much.
This is why its good to have a portable panel as well as fixed, it gives you a few options. If your battery needs a lot of charge then you can put out both panels. But if really hot you can park in the shade (hopefully) and still charge battery off the portable.
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