Battery Life Estimator — Engineering Tools

🔋 Battery Life Estimator

Estimate runtime from battery capacity and load current. Supports duty-cycle mode for devices with active and sleep states.

Battery Parameters

Capacity

mAh

Depth of Discharge

System Efficiency

💡 Depth of Discharge (DoD): Lithium cells are typically discharged to 80–90% DoD to maximise cycle life. Lead-acid: 50%. NiMH: 80–100%.
System Efficiency: Accounts for DC-DC converter losses, self-discharge, and temperature derating. 85–95% is typical.

Load — Simple (Constant Current)

Runtime = (Capacity × DoD% × Efficiency%) / I_avg

Average Load Current

⚠ Please enter valid battery and current values.

Results

Battery Level

Load — Duty-Cycle Mode (Active + Sleep)

I_avg = I_active × D + I_sleep × (1 − D) | D = t_active / (t_active + t_sleep)

Active Current

Active Time

Active Time Unit

Sleep Current

Sleep Time

Sleep Time Unit

⚠ Please enter valid values (all fields required).

Results

Battery Level

Common Battery Capacities — Reference

Battery	Nominal Voltage	Typical Capacity	Chemistry
CR2032 coin cell	3.0 V	210–240 mAh	Li-MnO₂
AA alkaline	1.5 V	2400–3000 mAh	Alkaline
AA NiMH	1.2 V	1800–2800 mAh	NiMH
18650 Li-ion	3.7 V	2000–3600 mAh	Li-ion
21700 Li-ion	3.7 V	4000–5000 mAh	Li-ion
LiPo (typical wearable)	3.7 V	100–400 mAh	LiPo
LiPo (phone-size)	3.7 V	2500–5000 mAh	LiPo
9V alkaline	9.0 V	400–600 mAh	Alkaline