Home Inverter & Battery Capacity Calculator India — VA & Ah Sizing
Calculate the perfect inverter capacity (VA) and battery size (Ah) for your Indian home. Supports fans, lights, TV, fridge, and AC load with realistic power cut backup duration and tubular vs lithium battery comparison.
Appliance Power Outage Load Configuration
Keeps food cold during extended blackouts.
Requires minimum 2.5 kVA / 24V inverter.
Typical power cuts in India range between 2 and 4 hours.
0.8 kVA Pure Sine Wave Inverter + 1 × 150 Ah Battery
Guarantees a true 4 hours of uninterrupted backup for your 527W load without tripping or dangerous voltage sag. Pure Sine Wave protects sensitive laptop and fridge motherboards.
Frequently Asked Questions
Q:How do I calculate inverter VA capacity from total appliance Watts?
Inverters are rated in Volt-Amperes (VA), whereas appliances are rated in Watts. To convert Watts to VA, divide total wattage by the power factor (typically 0.8) and add a 20–25% safety surge headroom: Inverter VA = (Total Watts / 0.8) × 1.25. For example, a 500W load needs a (500 / 0.8) × 1.25 = ~780 VA (or standard 900VA / 1 kVA) inverter.
Q:What is the difference between Tubular Lead-Acid and Lithium batteries for home inverters?
Tubular lead-acid batteries (150Ah, 200Ah) cost ₹12,000–₹18,000 per unit, last 5–7 years, require maintenance (distilled water top-up), and support 1,200–1,500 charge cycles. Lithium Iron Phosphate (LiFePO4) batteries cost ₹25,000–₹40,000 but last 10–15 years, support 3,000+ cycles, are maintenance-free, and are 30% lighter. Lithium pays back in 6–8 years compared to replacing tubular batteries twice.
Q:How many Ah battery do I need for 4 hours of power backup in India?
Battery Ah = (Total Load in Watts × Backup Hours) / (Battery Voltage × Efficiency). For a 400W load over 4 hours with a 12V battery at 80% efficiency: (400 × 4) / (12 × 0.8) = 167 Ah. You would need a 180Ah or 200Ah tubular battery. For a 24V system (two 12V batteries in series), each battery only needs to be 100Ah.
Q:Can I run a refrigerator on a home inverter during a power cut?
Yes, but with important caveats. A typical 250L refrigerator draws 150–200W during normal operation but has a high motor startup surge of 600–800W. Your inverter must handle this surge — a 900VA inverter may trip. A 1.5 kVA or 2 kVA inverter is recommended if you want to run a fridge + other appliances simultaneously. Also, running a fridge significantly reduces backup duration: a 200Ah battery will last only 3–4 hours instead of 8 hours for lights and fans.
Q:What is the difference between a home UPS and a home inverter?
A Home UPS (Uninterruptible Power Supply) switches to battery within 10–20 milliseconds of a power outage — fast enough that computers, TVs, and sensitive electronics do not restart or lose data. A conventional home inverter has a 20–200 ms switching delay, which can cause computers to restart and some electronic devices to malfunction. Home UPS systems are recommended if you work from home or have a desktop PC, while standard inverters are sufficient for fans, lights, and TVs.
Related Home Cost Tools
Kagazo — 100% Free Sovereign Document & Exam Tools
Zero server uploads. Process passport photo sheets, 5-in-1 PVC ID cards, Aadhaar merges, and exam compliance in your browser RAM.