I’m posting this so that the experts can criticize this plan and tell me what’s wrong with it. Don’t hold back, the faster that I’m corrected the less time I spend being wrong.
While it cannot all be used, this system could produce $950+ worth of electricity per year according to the NREL website (5040w installed, 175 azimuth, 24 degrees elevation). My annualized average usage after my electric car purchase is $1621/year so that’s enough to erase 57% of my electric bill. To start, I want to extend my existing south facing screen porch room from 12x14” to 12x28” with material I already have from when I bought it screen room kit from Costco. The 18x solar panels (77”x33” each) will be at a 24 degree angle up from horizontal face 5 degrees east of due south. So that the top edge of the array will be flush to the house and just at the bottom of the second story windows. The idea is that the panels charge 8x large 6v or 12v deep cycle batteries in the basement, also power other A/C loads during the day, and then once I get home i charge my car up from any afternoon sun and then the 6-9KWH of energy stored in the batteries. if its cloudy or the car needs more power than was available that day, the 5000w inverter will see that there is no solar and the batteries are low and automatically switch over to the utility power pass though (or an auto-start natural gas/propane generator in a grid-down situation) and provide power to my car, the batteries, and any other loads connected to it. The lead batteries will last 10 years with proper maintenance and all other parts of the system 20 years. the system will cost ~$4000, the payback will be 4.5 years, and in the systems 20 year life it will save $14,400 of spending on power, an equivalent to a >10% APR if I invested that $4000 in vanguard. Not to mention it will work with no grid power forever, its off-grid, stand alone.
Here is a complete system diagram, but some of these system components already exist and work correctly, like to 10 circuit transfer switch that’s connected to NG generator and the L2H works which I talked about in a different post: https://ibb.co/SXfnxFy
In the December, the lowest production month, the system will make ~281KWH, and this is just a little bit less than my car used last December. My leaf soaked up 11KWH/day or 336KWH. However in summer, when the solar panel and inverter system will be producing 450KWH extra per month after charging my car. I can use that excess energy to run an little AC unit. My central AC unit takes too much power to run, it’s on a 30a breaker or at least it needs 30A/7200w+ to start. So instead i could install a "mini split" system that only runs on 220V/5A or 1100w. These systems have an exterior unit, just like a normal central AC system and an indoor unit like a hotel or apartment. my idea is to install that indoor unit in the basement and the outdoor unit just outside the house, but in close proximity to the indoor unit. the solar power system will charge the batteries first, and then when they are full I’ll have the system automatically start running the AC unit as long as solar power is available. this will have two main effects with the indoor unit in the basement it will eliminate the need for running a dehumidifier, which costs me $30/month to run a 70 pint unit in the hot humid summer, also i can set it up to run the furnace fan so it will suck all that cold basement air in and blow it around the house. The existing AC system will function normally and will be controlled with the existing thermostat and run on Edison power just like normal, its just it will be getting a boost with this system. In general everything has to work exactly like how you would expect, in case if someone comes after me they will need everything to work in an intuitive way, so I cannot make myself too built into it.
costs first the solar panels
18x used 280w (5040w total) solar panels $1400 delivered
5000w inverter, $530
8 deep cycle batteries $680
220v mini split system $400
Various electrical parts $400
roof frame, steel uni-strut $500
Inverter:https://www.aliexpress.com/item/5kva-40 ... 50825.html
panels:https://www.ebay.com/itm/Used-280W-72-C ... 2459000473
mini split:https://www.ebay.com/itm/Premium-Mini-S ... 3107553841