About the Hybrid System Split
Hybrid solar system split sizing determines the optimal ratio between solar PV, battery storage, and grid/DG backup in a hybrid system — maximising solar self-consumption and backup autonomy while minimising cost. The goal is to size each component so that the combination meets load requirements across all operating modes: solar-only, battery discharge, and grid/DG fallback.
How to calculate it
- 1Profile the load: total daily kWh, peak kW, and the hours when grid power is most expensive or unreliable (typically 6–10 PM in India).
- 2Size solar first: target 100–150% of daytime load (excess charges batteries).
- 3Size battery: target 4–8 hours of critical load (not full load) during outage or peak ToU window.
- 4Size inverter/PCU: must handle peak load kW, not just average. Hybrid inverter rating ≥ peak load × 1.25.
- 5Grid/DG contribution: handles the residual load that solar + battery cannot cover — size to the gap.
- 6Validate: simulate a typical day and a worst-case (no sun for 3 days) to check adequacy.
Worked example
A home with 8 kWh/day load, 2 kW peak. Solar: 3 kWp (generates ~15 kWh/day, enough for load + battery charge). Battery: 10 kWh usable (covers 5 hours of critical 2 kW load). Hybrid inverter: 5 kVA (handles 2 kW peak with 2.5× buffer). Grid tie: handles top-up on cloudy days. Self-consumption ratio: ~85%.
What you can calculate
- Source split %
- Daily cost
- DG sequencing
- SoC management
Frequently asked questions
What is the difference between a hybrid solar system and an off-grid system?
A hybrid system maintains a grid connection (or generator connection) as a backup alongside solar + battery — ensuring power continuity even when battery is depleted. An off-grid system has no grid connection and must be sized to meet 100% of load from solar + battery alone, requiring significantly larger battery capacity to survive multi-day low-irradiance periods. Hybrid systems are far more cost-effective for most Indian homes and businesses in grid-connected areas.
How do I decide the solar-to-battery ratio in a hybrid system?
A common starting rule: battery capacity (kWh) ≈ 1–2× solar array size (kWp). For a 3 kWp system: 3–6 kWh battery. If the primary goal is backup during outages, size battery to cover critical loads for 4–8 hours. If the primary goal is ToU arbitrage (avoid 6–10 PM peak tariff), size battery to store the surplus solar generation available from 10 AM–4 PM — typically 50–70% of the solar array's daily output.
Ready to build your solar project?
Get free quotes from verified EPCs and installers across India.
You might also need
System Designer
Design custom solar system with component selection and layout optimization
OpenPanel Requirements
Calculate number of panels needed based on your energy consumption and roof space
OpenBattery Bank Sizing
LFP / NMC / Lead-Acid bank sizing with DoD, autonomy hours, temp derating, and S×P config
OpenSolar Plant Size
Size your plant in kWp from load (kWh/day) or available rooftop area
OpenInverter Sizing
Recommend inverter kVA from DC array kWp with DC:AC ratio and phase checks
OpenString Sizing
Temperature-corrected Voc / Vmp string sizing with MPPT window and safety margin checks
Open