How Do I Build a Large Off-Grid Solar System for 4,500 kWh a Month?

I’d be careful with your sunlight estimates; 5 hours would be more typical in sunny places like the Southwest, but you'll probably see closer to 3 hours in Rhode Island. For accurate predictions, check out PVwatts, which factors in local weather conditions. Just keep in mind, 4,500 kWh monthly is a lot—my total yearly consumption is about 10,000 kWh, mostly from AC in the summer!

That's a hefty power requirement, around 150 kWh a day, and it’s definitely a challenging project. An all-in-one system could include something like EG4 Gridboss with 3 EG4 Flexbosses and around 9 EG4 Wallmount Batteries, giving you roughly 130 kWh of backup—not enough for an entire day of backup, though. Expect to need about 50 kW of panels, which could run you around $65k to $70k, not counting wiring and all the necessary components. Plus, you might need a strong generator since those panels will be underperforming during those harsh winter months in the Northeast.

You'll likely need a system over 30 kW. If you're thinking about future upgrades, consider if that's adding more panels or just bigger inverters. It’s often cheaper to build a solid system now rather than upgrading later, especially since parts may not be available in the future. For efficiency, you might want to look at purchasing inverters that match the final size you want, so you can gradually add more panels without having to replace everything.