Total Draw
68 mA
Watts
0.34W
Runtime
25.5h
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Inputs
Result
Inputs
Result
An Arduino Uno draws 46 mA idle, Nano 19 mA, and Mega 70 mA. ESP32 draws 80 mA idle but up to 500 mA with WiFi active. Always add sensor and actuator draw for total project budget.
| Board | Idle | Max | Voltage |
|---|---|---|---|
| Uno | 46 mA | 200 mA | 5V |
| Nano | 19 mA | 200 mA | 5V |
| ESP32 | 80 mA | 500 mA | 3.3V |
| ESP8266 | 70 mA | 300 mA | 3.3V |
A typical 9V battery has 500-600 mAh capacity. An Arduino Uno with basic sensors (100 mA total draw) lasts about 4-5 hours. For longer projects, use 18650 Li-Ion cells (2600+ mAh) or AA batteries.
Use sleep modes (power-down saves 99% power), disable unused peripherals, lower clock speed, use 3.3V boards when possible, and minimize WiFi/Bluetooth wake time. Power-down mode on Uno reduces draw to ~0.1 mA.
Digital pins can source up to 20 mA each (40 mA absolute max), with 200 mA total across all pins. For sensors drawing more than 20 mA or motors, use external power through a transistor or MOSFET.
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Last Updated: Mar 20, 2026
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