A Louisiana homeowner looking to expand a home battery backup setup got a jarring estimate when they were quoted $24,000 to add a Tesla Powerwall 3 to an existing Powerwall 2. The homeowner took to Reddit's r/solar community to "get some opinions." Here's what to know The original poster explained: "I was looking at adding a PW3 to an existing PW2 system since they are now compatible. I was quoted at $24,000 which seems quite high to me, but I …