Estimate how battery size and load affect runtime before you overbuy or underbuild.
Enter the average load and desired operating time. The estimate allows for inverter loss and unused reserve capacity.
Educational estimate only. Startup surges, temperature, cable loss, battery limits, and manufacturer requirements can change final capacity. Have critical and code-sensitive systems verified by a qualified professional.
Required watt-hours = average watts x hours, adjusted for efficiency and reserve. Use average demand for energy sizing, then check startup surge separately when the system powers motors, pumps, compressors, microwaves, or air conditioners.
| Average load | Energy for 8 hours | Example planning context |
|---|---|---|
| 50W | 400Wh | Router, lighting, and small electronics |
| 200W | 1,600Wh | Mixed electronics or an efficient refrigerator average |
| 500W | 4,000Wh | Several controlled backup loads |
| 1,000W | 8,000Wh | Larger backup loads; surge must also be checked |
Use this calculator to narrow battery size, charging needs, solar requirements, or retailer choices before you move into product research.
These offers focus on backup and portable power options where load duration and outage expectations are driving the decision.
Some offers may open Amazon search results until a stable direct product page is confirmed.
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