I bought a cheap used Goal Zero Escape 30 Solar Briefcase to keep my starting battery charged (I have a LX470 w/ a parasitic draw that I have not been able to locate). I'm looking for the smallest solar controller I can find to wire the suitcase panel to charge the battery. I found a few on Amazon, but not sure if there is a better one. I currently run the Victron Solar Smart on my house battery, but don't feel the need to spend $100 for a controller just being used to charge the starting battery.
Amazon product ASIN B07CK2PCC7
Amazon product ASIN B07NPDWZJ7
Amazon product ASIN B07CK2PCC7
Amazon product ASIN B07NPDWZJ7