Dee ✭✭

Not well informed re solar and new to off grid power user with several questions. My property is located in Upstate NY, hit and humid in summer with bitter cold winters.  I have purchased three different inverters, and two 12v auto batteries used to run LED lights, a 60w incandescent, the fan for a 30,000 btu propane heater, and as a test, a highly efficient small refrigerator with varying degrees of success. My electrician suggested a solar system to recharge the batteries after running them parallel. After researching, I understand the concept and recognize the need for proper setup as well as analysis of power needs. My 400w emergency inverter made to take power from a battery installed in a vehicle gives 30-35 hours running either lights or heater fan, and would not power the frig. The 2000w max/900w continuous inverter ran the frig perfectly during hot summer for 4.5 hours before beeping. I then bought an inverter labeled 3000-4000-5000w which claims to be sufficient for power tools. The two larger inverters say Solar/sine wave inverters. I also purchased the 25w solar panel kit and a 100w regulator from Harbor Freight.  I would like to run a parallel array and set the solar panel to recharge it. I want to run a very dependable 750w heater with thermostat to keep the temperature above 48 degrees in a mobile home. The panel would be mounted vertically facing due south with no obstruction for at least 100 yards where leafless trees help to block wind but no light. The heater would be plugged into a surge protector and connected by a 25’ outdoor rated extension cord. I want to set the array into a fiberglass bathtub that is not connected to a water source (no faucet), to avoid contact with wood or metal or accidental contact by humans or pets. Am I close to meeting my needs or setting myself up to fail? Thank you for your help!