As has been mentioned, a good controller is everything! Only really small panels get by without one, the 5 watt panel that keeps the Whaler battery alive is too small to damage anything. The 50 watt panel on Coquina goes through a Morningstar controller that was about $35 and has worked fine for many years. Morningstar is not the cheapest place to find controllers, but they are good and reliable unlike random Chinese FleaBay stuff.
Joe Della Barba Coquina C&C 35 MK I Kent Island MD USA October is the time to show your appreciation with a small contribution to this list to help offset the costs. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu