Batteries can be quickly drained if running a furnace fan or creating heat, like using a microwave if you have a large inverter. You need to be aware of the draw of each appliance and how long you can safely use the battery(s) to power them.
Most batteries are not designed to be discharged over 50% without doing damage damage over the long haul to the battery. We boondock in AZ for months on end and you must learn how to monitor use, especially if you hit cloudy weather which means less stored power being generated.
Solar is great but the real key is how much energy can you store?? Lots of guys here know more than me - hoping they will chime in for you.