I have a 2017 Hummingbird 17FD ... it has a solar connector to recharge the battery. Question: If I am only using a small 10W solar panel to tickle during the daytime, do I need to add a controller for voltage flow? I have used permanent solar panels before for a boat and a controller is essential. However, they were bigger panels and on permanent use. If I do need a controller, is there any recommendation for a solar panel tickler that includes a controller or should I buy one and mount it somewhere on the trailer?