Solar & Power Calculator
Instantly calculate Battery Backup, Solar Panel & Inverter sizing
Ultimate Guide to Solar, Inverter, and Battery Calculations
Planning a solar power setup or buying a new inverter and battery for your home or office can be confusing. To make the right investment, you need accurate calculations. Our Advanced Solar and Battery Calculator is designed to help you easily determine battery backup time, solar panel requirements, and the correct inverter capacity without any complex manual math.
How to Calculate Battery Backup Time?
Battery backup time depends on three main factors: Battery Capacity (Ah), Battery Voltage (V), and your Total Load (Watts). Our tool uses the standard formula to estimate how long your appliances will run during a power cut.
- Battery Capacity (Ah): Ampere-hour indicates how much energy a battery can store. For homes, a 150Ah or 200Ah battery is standard.
- Battery Voltage: A single standard battery is 12V. If you connect two batteries in series, it becomes 24V.
- Inverter Efficiency: No system is 100% perfect. Most lead-acid/tubular battery setups have an efficiency of around 80% to 85%, which means some power is lost during DC to AC conversion.
Sizing Your Solar Panels
If you want to go off-grid or reduce your electricity bills, you must install the correct number of solar panels. To calculate solar requirements, enter your daily power consumption (in Watt-hours) and the peak sun hours in your region.
Peak Sun Hours: This refers to the hours per day when solar irradiance averages 1000 watts per square meter. In most regions, this ranges from 4 to 6 hours. Our calculator also adds a Safety Buffer (20%-30%) to account for cloudy days, dust on panels, and wiring losses, ensuring you never run out of power.
Choosing the Right Inverter Size (VA vs Watts)
Many people make the mistake of buying an inverter based strictly on Watts. However, inverters are rated in VA (Volt-Amperes). To convert Watts to VA, we use the Power Factor (Cos θ).
- Power Factor: For residential loads (fans, TVs, lights), the power factor is usually around 0.8.
- Surge Buffer: Motor-based appliances like refrigerators and water pumps require extra power to start. Our calculator automatically adds a 20% surge buffer to recommend the safest inverter capacity.
Basic Power Conversions
Understanding electrical terms is crucial for any DIY enthusiast or homeowner. Use our built-in power converter to switch between values seamlessly:
- Watts = Volts × Amps: Calculate total power consumption if you only know the current (A) and voltage (V).
- mAh to Ah Converter: Small batteries (like in smartphones and power banks) use milliampere-hours (mAh). Divide by 1000 to get the standard Ampere-hour (Ah) rating. For example, a 5000mAh phone battery is equal to 5Ah.
Disclaimer: These calculations provide highly accurate estimates based on standard electrical formulas. Real-world results may vary slightly based on appliance age, wire quality, and battery health.