I was camping with some friends this past weekend in the rain. Various setups and I was the only FWC onsite. Looking at the other setups I mentioned the Hawk had an additional SOLAR plug at the back so I could plug a second backup solar when needed. It was a rainy weekend and batteries were getting low. I mentioned I might plug another guys portable Solar panel in for some extra charge. My "knowledgeable" buddy said that the panel had to be a same power as my 160W on top???? Does anyone know if this is true? I always assumed I was fine as long as polarity matched. Do they need to have the same power rating?