Inverter & Battery Calculator
Size a home backup system to your needs: enter the load you want to run and the backup hours, and get the inverter VA rating and the battery capacity (Ah). Size to your essential loads, not the whole house. This is an indicative planning aid — confirm the final sizing with a licensed electrician and battery supplier.
12 V uses one battery; 24 V / 48 V use 2 / 4 in series for larger systems.
Sized so the inverter covers the load you run at once (watts ÷ 0.8), and the battery carries it for 3 hours (watts × hours ÷ (voltage × 0.8)). Add margin and avoid habitual deep discharge to protect battery life.
Indicative only. This uses a typical power factor and a combined efficiency/usable-capacity allowance; real backup time also depends on battery type, age, temperature, depth of discharge and load pattern. It does not size for heavy motor-starting loads (ACs, pumps) — those need professional sizing and often a generator. Confirm the inverter, battery and the changeover switch with a licensed electrician and battery supplier.
Related Guides — Deep-dive reading
Inverters & Batteries: How They Work & How to Size Them
The silent workhorse of Indian home backup — how an inverter turns battery power into mains, what the VA rating means, why sine-wave matters, how to size the inverter to your load and the battery to your backup hours, and how to keep the system healthy.
Electrical & WiringElectrical Backup Assessment for Home Security in India
The under-appreciated gap: a power cut silently disables your cameras, NVR, alarm, gate motor, router and Wi-Fi, leaving the home undefended exactly when it may be most vulnerable. How to map the security load, test what your inverter really covers, size backup, and protect against grid surges.
SecurityHome Generators: Portable, Standby, Sizing & When You Need One
When a battery isn't enough — how a generator produces power for heavy loads and long outages, the difference between a portable set and a fixed standby DG, how they are sized, the fuel, noise and emission realities, and whether a home actually needs one.
Electrical & WiringRelated Tools — You may also find these useful
Security Backup Power Calculator
Size a UPS/inverter and battery to keep CCTV, NVR, router and alarm running through a power cut — load, Ah, VA and cost.
Backup PowerAI Electrical Assistant
Ask anything about your home's electrics in plain language — RCCBs, phases, backup, solar, tripping and more. Understand and decide; an electrician does the work.
AI ToolAI Electrical Brief Builder
An AI assistant that turns your needs into a clear electrical requirements brief — room-by-room points, circuits, protection, backup — to hand your electrician.
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