Start with your monthly bill units — every case below is scaled to that home. Compare legacy net metering, net billing on-grid, and hybrid + battery — plus Case 4: an automated sizing optimizer that finds your best panel & battery combination. All calculations run in your browser.
Your Home — Monthly Electricity Consumption
1. Results
Payback (years) — shorter is better
How Your Generated Solar Energy is Used
Case 1 — Legacy net metering
Case 2 — Net billing, on-grid, no battery
Case 3 — Net billing, hybrid + battery
Case 4 — Recommended optimal size
2. Adjust the assumptions — each case has its own
Changing a value adjusts only its own case. Battery settings appear only in Case 3, because Cases 1 and 2 have no battery. Case 4 follows Case 3's load, tariff, and hardware price sliders and automatically solves for the optimal panel and battery size.
Case 1 — Legacy net metering
On-grid inverter, no battery. Post defaults: low daytime use (15% day / 85% night).
Case 2 — Net billing, on-grid
On-grid inverter, no battery. Post defaults: low daytime use (15% day / 85% night).
Case 3 — Net billing, hybrid + battery
Hybrid inverter + battery. Post defaults include daytime load shifting (30% day / 70% night).
Case 4 — Optimizer Logic
Follows Case 3's tariffs, loads, and unit prices, testing every valid panel (3–20 kW) and chargeable battery (1–30 kWh) combination:
- Sweet Spot (Fastest ROI): Finds the shortest payback period among hybrid systems that cut your electricity bill by at least 50% — preventing oversized panels that dump cheap Rs. 10 units to the grid.
- Maximum 8-Year Net Profit: Picks the size that maximizes cumulative 8-year cash savings minus upfront CAPEX.
- Maximum 10-Year Net Profit: Picks the size that maximizes 10-year net cash savings (approx. 6,000 LiFePO4 cycles).
3. How the maths works
- Daily Energy Balance: Solar generation first covers the hybrid inverter's daytime standby draw (0.4 kWh) and household daytime load. Leftover solar charges the LiFePO4 battery at 92% round-trip efficiency (8% conversion loss). Any remaining solar is exported at the net-billing export tariff. At night, stored battery energy supplies the inverter's night standby draw (0.8 kWh) and household night load; any remaining night load is imported from the grid.
- Accurate Self-Use Accounting: Only energy actually consumed by your home appliances is credited in Home self-used and Night batt. saving. Inverter parasitic draw is treated strictly as system overhead.
- Net Billing vs. Legacy Net Metering: Under Net Billing,
Annual Bill = Imports × Import Tariff − Exports × Export Tariff(floored at zero). Under Legacy 1:1 Net Metering, exported units offset imported units 1-for-1 before any excess is valued at the export rate. - Dynamic Sizing Guardrails: You can freely adjust the Solar System Size slider (3–20 kW). The battery slider automatically caps at the maximum usable kWh that your chosen panels can actually charge on an average day.