Hey everyone! I'm diving into solar power for my home and need some guidance on sizing my system. I don't aim to cover all my energy needs immediately, but I'm uncertain about how to size everything properly since I'm new to this. I've been looking at my power company's data from August 2022, and I'm considering starting with the EG4 FlexBoss21 inverter paired with either one or two batteries to expand my system later. My historical usage rarely exceeds 12+ kW in an hour, so I think one inverter could be sufficient, but if I were to rely entirely on battery backup during cloudy days, I'd likely need more batteries.
For solar panels, I'm looking at a pallet of 450W panels for a total of 14,400W or a pallet of 400W panels (also 14,400W). I'm just worried if either option might be too much. On average, I can expect about 5 hours of good sunlight, which could yield around 70 kW if conditions are perfect. With losses in mind, how much should I realistically expect? I have a lot of open land for the panels and am using tilt mounts for better sun exposure. Also, using the PVWatts calculator, I estimated my annual production at 17,000 kWh, but I'm open to corrections on my assumptions. Would this amount of panel capacity be considered overkill, or would it help meet my needs? I'd be cool with generating excess power since I could sell it back to my utility.
3 Answers
When I sized my system, I looked at my highest historical usage instead of just monthly averages. For instance, adding your top monthly uses can help avoid underproduction. If you're planning on getting an electric vehicle, factor that in—it can add about 4,000 kWh to your needs. You might feel like you’re oversizing your system now, but it could be a smart move in the long run, especially for winter sunlight hours. Always think of panel degradation over time, too!
For a reliable setup, consider at least two to account for winter and cloudy days, but it depends on your total energy demands!
Make sure to consider your roof's potential shading issues before sizing your system. Just a heads up—14kWh refers to your average use, while the kW rating of your inverter indicates peak capacity. If your daily load spikes to 28kW for a short time, you could run into problems if you base everything just on averages. Are you looking to go fully off-grid or keep your grid connection for backup? That might influence your sizing decisions significantly.
The roof is mostly unshaded, but I prefer ground-mounted panels for easier access and expansion. I do want to eventually go off-grid, but starting with a hybrid system seems more practical!
Good call! Ground mounts simplify maintenance and scaling your system. Just keep in mind that going fully off-grid takes careful planning and might require additional battery capacity.
I’d suggest oversizing your solar setup a bit! Having additional capacity helps, especially with battery storage for night use. Plus, don’t forget about cloudy weather; it happens, and you’ll want to remain comfortable at home without any power hiccups. Also, think about using your excess energy to heat or cool your house, making it more efficient!
Thanks for that tip! We currently charge an electric car at home, so I'll include that in my calculations. How many batteries do you think I would need if I go for 14.3 kWh units?