I somewhat agree with this but for different reasons. If you buy 2-panels, you will get a controller for each one. One controller to each panel tied together downrange of the controllers would float each solar panel from the other one and allow each controller to only have to deal with the output of one solar panel.


But I would make a guess that this would give you problems because the output from one panel and controller could easily effect the other controller by fooling it into thinking the battery has more of a charge then it really does.


The best way to tie two solar panels together is to run both of them into one controller that is made to handle the combined output of both of them. Solar charge controllers are not super expensive, so all you need to do is to buy a bigger solar controller.


Wind power controllers are expensive (they need a dump load and generally have to handle much more power then a solar controller) but solar ones are not too expensive.