Solar System & Battery Sizing for 1,800 kWh/Month in Illinois, USA
Complete photovoltaic engineering breakdown for a 1,800 kWh/month (60.0 kWh/day) electricity profile in Illinois, USA (4.4 Peak Sun Hours/day).
Technical Specification Table — 1,800 kWh/Month Solar System (Illinois, USA)
| Monthly / Daily Electricity Consumption | 1,800 kWh/month (60.0 kWh/day) |
| Location Peak Sun Hours (PSH) | 4.4 hours/day (Illinois, USA) |
| Required PV System Size (80% Performance Ratio) | 17.16 kWp DC |
| Number of Solar Panels (440W N-Type Bifacial) | 39 panels |
| Roof Area Required | 79.9 m² (860 sq ft) |
| Recommended Hybrid Inverter Rating | 15.3 kW AC |
| Recommended LiFePO4 Battery Storage (85% DoD) | 45.9 kWh Nominal (39.0 kWh Usable) |
| Estimated Annual Output | 22,047 kWh/year (~1,837 kWh/month) |
| Estimated System Turnkey Cost (Before Tax Credits) | $46,332 |
| Annual Electricity Bill Savings (@ $0.17/kWh) | $3,748/year ($312/month) |
Frequently Asked Questions
How many solar panels are needed for 1,800 kWh per month in Illinois, USA?
With an average of 4.4 Peak Sun Hours per day in Illinois, USA and an 80% system performance ratio, a monthly usage of 1,800 kWh (60.0 kWh/day) requires a 17.16 kWp solar array, which equals 39 standard 440W N-Type solar panels occupying 79.9 m² (860 sq ft) of roof space.
What size solar battery bank do I need for 1,800 kWh/month?
To cover evening and overnight loads (65% of daily consumption at 85% LiFePO4 depth of discharge), a 45.9 kWh nominal (39.0 kWh usable) LiFePO4 battery bank paired with a 15.3 kW hybrid inverter is recommended.
How much money will a 17.16 kW solar system save in Illinois, USA?
Generating approximately 22,047 kWh per year at an average local tariff of $0.17/kWh, the system saves $3,748 per year ($312/month) with an estimated payback period of 12.4 years.