Inverter & Battery Sizing Calculator 2026 – Backup Time & VA Estimator
Calculate the exact inverter VA rating, required battery capacity (Ah), and real-world backup hours considering Depth of Discharge (75% DoD) and inverter efficiency.
1. Select Running Home Appliances (Total Active Load)
Set the quantity of appliances you need to run during power outages:
Calculated as (Total Watts ÷ 0.8 PF) × 1.25 buffer. Prevents tripping during motor inrush surge currents.
3. Battery Capacity (Ah) & Live Backup Gauge
Select your battery capacity (Ah) rating or enter a custom size:
📌 Recommended Inverter & Battery Purchase Kit for Your Home
🎯 4. Target Backup Duration Sizing Tool
Calculate the exact battery Ah you need to purchase for your desired outage duration:
How to Use the Inverter & Battery Sizing Calculator
Select Running Appliances
Add or adjust quantities of fans, lights, TV, and Wi-Fi router to compute total continuous running wattage (W).
Review Inverter VA Rating
The calculator computes VA using standard 0.8 Power Factor and a 25% safety buffer, recommending standard market sizes (650 VA to 2500 VA).
Select Battery Capacity (Ah)
Pick your battery size (100Ah, 150Ah, 180Ah, 200Ah, 220Ah) to see live backup duration with 75% DoD safety limits.
Inspect Recommended Combo Kit
Get actionable advice on the ideal Pure Sine Wave Inverter and Tall Tubular or Lithium battery package for your home.
🖼️
Home Inverter & Battery Sizing: The Zero-Error Engineering Methodology
Most Indian home owners face inverter disappointment because local dealers calculate backup by simply multiplying Volts by Ampere-hours. In practical power engineering, backup duration is heavily governed by the Depth of Discharge (DoD) of lead-acid chemistry (75%), the Inverter Power Factor (0.8 PF), and DC-to-AC inversion losses (15%). Understanding these parameters ensures your fans, lights, and appliances run without unexpected blackouts.
Inductive loads like fan motors draw reactive current. A 25% safety headroom prevents overload tripping.
Factor in 75% DoD (to prevent plate sulfation) and 85% inverter conversion efficiency.
Calculate exactly what battery capacity to purchase for your desired power outage hours.
📊 Standard Inverter & Battery Selection Matrix for Indian Homes
| Home Setup | Typical Load (W) | Recommended Inverter | 100 Ah Backup | 150 Ah Backup | 200 Ah Backup |
|---|---|---|---|---|---|
| 1 BHK (2 Fans, 3 LEDs, TV, Wi-Fi) | 250 W | 850 VA (12V) | 3.1 hrs | 4.6 hrs | 6.1 hrs |
| 2 BHK (3 Fans, 5 LEDs, TV, Wi-Fi, Laptop) | 360 W | 1100 VA (12V) | 2.1 hrs | 3.2 hrs | 4.3 hrs |
| 3 BHK (4 Fans, 8 LEDs, TV, Fridge, Router) | 550 W | 1500 VA (24V) | 1.4 hrs | 2.1 hrs | 2.8 hrs |
| Heavy Home (All lights + Refrigerator + Cooler) | 800 W | 2000 VA (24V) | 1.9 hrs (2x100) | 2.9 hrs (2x150) | 3.8 hrs (2x200) |
⚡ Pure Sine Wave vs Square Wave
Always opt for a Pure Sine Wave inverter. Square wave or modified sine wave units produce high harmonic distortion that causes ceiling fans to hum loudly and can destroy delicate switch-mode power supplies (SMPS) inside modern Smart TVs, routers, and laptop chargers.
🔋 Tall Tubular vs Flat Plate Battery
For Indian power grid conditions with frequent load-shedding, choose Tall Tubular batteries. Their spine technology resists active material shedding, enduring 1,200 to 1,500 charge-discharge cycles compared to just 500 cycles for short flat-plate automotive batteries.