We are looking at a used solar panel as an add on with one we already have on our RV. However, the glass/plastic cover over the top (sun)side of the panel is shattered. When you test the panel with a tester, it is still generating power to the max but we are concerned about perhaps water getting into the cells and causing a problem. The owner said he had sprayed it with water recently, and had also used it for a year without a problem. We are wondering about it. Could the cover be replaced easily, would that be necessary, and if so what would you use. He said the dealer told him that since it was working there was no problem, and that this is not unusual. ???? What do you think? Thanks.