Ultra-miniature DIY solar projects?
Ultra-miniature DIY solar projects?
What exists right now for someone who wants to make a very small solar project?
A family member of mine was hoping to put 1 or 2 panels on the roof of their ADU to power maybe just the small window air conditioner in it, or at least offset a lot of its energy use. Is there anything practical for doing this that doesn't cost multiple thousands of dollars?
In my imagined setup, there would be 1-2 panels on the roof connected to a cheap consumer battery (something like a small ecoflow). The appliance would try and run only off the battery, but if the battery charge level dipped to low it would have some controller that would switch it to grid power until the charge level was back up. I would not want to feed any power into the grid, but I wouldn't want the person living in the space to have to manually switch the power source between the battery and a regular outlet.
this earlier post might give you an idea where to start
When the grid is present it's much cheaper and easier to feed inverted solar power to the house and draw the A/C power from the house. Since the solar would be small there would never be any power from it reaching outside the house. This meets the "at least offset a lot of its energy use" goal with minimal expense and complication.
A system like that, it appears to me, doesn't have any kind of controller associated with it. What happens if more power is being produced than the house is using? Is there a risk of accidentally feeding back through the meter and causing damage/getting in big trouble with your utility? There would be times when no appliances are running to eat up energy during the day.
Not arguing, to be clear. I have never done this and there's some piece of the puzzle of DIY solar that has not clicked for me.
There is no charge controller since there is no charging. The grid tie inverter runs the array at Vmp under present conditions.
A toy system isn't in any danger of outstripping house demand; the average US household consumes something like 30kWh every day.
Using the maximal version of the setup in that list (400w) somewhere representative like Salt Lake City on the best month would make something like ~2.6kWh/day, and a max output of 340w. It won't even keep up with the A/C load.
The missing part is the math, which tools like PVwatts will help clarify.