How to Size a Hybrid Solar System: A Step-by-Step Worksheet

Correct sizing is what separates a hybrid system that delights the customer from one that disappoints. Here is the five-step method our engineers use, which you can apply directly to customer projects.

Step 1: Audit the loads

List every load with its power draw and daily run hours. The result is a daily energy budget in kWh. Don’t guess — a data logger or the customer’s utility bills beat estimation every time.

Example: a household using 12 kWh/day with a 6 kW evening peak.

Step 2: Size the PV array

Divide the daily budget by the local peak sun hours, then add 15–25% for system losses, battery round-trip and panel degradation.

Example: 12 kWh ÷ 4.5 sun hours × 1.25 ≈ 3.3 kW → a 4 kW array (8 × 500 W panels) leaves margin.

Step 3: Size the battery bank

Decide the backup target: essential loads only (fridge, lights, router) or the whole house. Multiply by the hours (or days) of autonomy required, and respect the inverter’s maximum charging current — a battery bank too small to absorb PV output wastes generation.

Example: 8 kWh of storage (48 V × ~170 Ah usable) covers essential loads overnight with one day of autonomy.

Step 4: Select the inverter

The inverter’s continuous rating must exceed the simultaneous peak load, and its surge rating must cover motor starts. A 5 kW continuous / 10 kW surge unit — like our HV-5000 hybrid inverter — comfortably handles a 6 kW evening peak split across non-coincident loads with inrush margin.

Step 5: Check compliance

Confirm grid codes, export limits and certification requirements for the destination market before quoting. This is where OEM support pays for itself — we pre-configure market-specific firmware on the production line.

Need a review?

Send us your load audit and target market through the contact form — our engineers will review your sizing and recommend suitable models free of charge.