// LAB 12 · INTERACTIVE
Inverter battery backup time calculator
Enter your battery (V, Ah) and your load in watts — see how many hours your inverter or UPS will really last.
⚡ POWERING UP THE LAB…
// HOW IT WORKS
The idea in 30 seconds
- Battery energy (Wh) = volts × amp-hours. A 12 V 150 Ah battery stores 1,800 Wh.
- Backup (hours) = Wh × inverter efficiency ÷ load in watts. Efficiency is usually 80–90 %.
- For a long battery life, do not drain it flat: lead-acid ≈ 50–80 % usable, lithium (LiFePO4) ≈ 90 %.
- The inverter must also be big enough: VA × about 0.8 = the most watts it can run.
// READ THE FULL GUIDE
Step-by-step guide
Watch the lessons
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