Battery Life Calculator

The results are estimates based on ideal conditions. Actual battery life will vary depending on battery condition, age, temperature, discharge rate, and other environmental factors. New, high-quality cells at room temperature will provide the most accurate results.

Ah (amp-hours) and mAh (milliamp-hours) both measure battery capacity. 1 Ah equals 1000 mAh. Larger batteries typically use Ah while smaller batteries like phone batteries use mAh for convenience.

To convert watt-hours to amp-hours, divide the Wh by the battery's nominal voltage: Ah = Wh ÷ V. For example, a 50Wh battery at 12V would be 50÷12 = 4.17 Ah.

Battery life depends on many factors including temperature, discharge rate, battery age, and load variations. Cold temperatures reduce capacity, while high discharge rates can decrease efficiency. The calculator assumes constant load and ideal conditions.

Temperature is the biggest factor - cold reduces capacity while heat can damage batteries. High current draw also reduces efficiency. Battery age, chemistry type, and how deeply you discharge also significantly impact performance.

Yes, this calculator works for any battery type (lithium-ion, lead-acid, alkaline, etc.) as it uses basic capacity and current relationships. However, different chemistries have different discharge characteristics and efficiency curves.

Use a multimeter in series with your device to measure actual current draw. Many devices have variable consumption, so measure during typical usage. Check device specifications or datasheets for average consumption values.

For lithium batteries, avoid discharging below 20% for longevity. Lead-acid batteries shouldn't go below 50%. The calculator assumes full discharge, but stopping earlier will extend battery lifespan significantly.