Yes, Arduino boards absolutely can run on battery power, making your projects portable and independent of wall outlets.
Powering your Arduino board with a battery is a common and practical way to deploy projects in various environments. As stated in the documentation for boards like the Uno and Mega, "Make your Arduino projects portable by using a battery for power." These boards are designed with an external power input specifically for this purpose.
Powering Your Arduino Board
Arduino boards like the popular Uno and Mega are versatile and can be powered in several ways:
- USB Connection: Directly from a computer or USB power adapter.
- External Power Jack: A barrel connector (typically 2.1mm center-positive) on the board.
- VIN Pin: A pin on the board that bypasses the power jack but still goes through the voltage regulator (on most boards).
For battery power, you will typically use the External Power Jack or the VIN Pin.
Voltage Requirements
According to the documentation for the Uno and Mega, the boards can operate on an external supply with a voltage range of 6 to 20 volts.
It is important to note a specific detail from the documentation regarding lower voltages: "If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable." This means that while some batteries might technically be within the 6-20V range (like a 6V battery pack), using a supply below 7V can potentially lead to inconsistent performance or issues with components expecting a stable 5V supply from the board's 5V pin. Supplying voltage between 7V and 12V is generally recommended for optimal stability and efficiency of the onboard voltage regulator.
Choosing the Right Battery
Selecting the best battery depends on your project's power consumption, required runtime, size constraints, and voltage needs. Here are some common battery options:
- 9V Alkaline or Rechargeable Batteries: Simple and widely available, a 9V battery is a quick way to power many Arduino projects. They connect easily via a standard clip to a barrel jack adapter. However, they typically have lower capacity and are best suited for projects with low power consumption or short durations.
- AA or AAA Battery Packs: Using a holder for multiple AA or AAA batteries (e.g., 4xAA for ~6V, 6xAA for ~9V) can provide more capacity than a single 9V battery. Ensure the total voltage falls within the 6-20V range (ideally 7-12V).
- LiPo or Li-ion Battery Packs: Lithium Polymer (LiPo) or Lithium-ion batteries (like 18650 cells) are popular for their high energy density (more power in a smaller package) and often consistent voltage output.
- A single 3.7V cell isn't enough voltage for the VIN pin/power jack on standard 5V Arduinos like Uno/Mega.
- Using multiple cells in series (e.g., a 2S LiPo pack, which is ~7.4V) is a common solution that fits well within the recommended voltage range.
- Be aware that LiPo/Li-ion batteries require specific charging and protection circuits for safety.
- Nickel-Metal Hydride (NiMH) Rechargeable Batteries: Similar to Alkaline AAs but rechargeable. Four NiMH batteries provide about 4.8V (not enough for VIN/power jack), while five provide 6V and six provide 7.2V, fitting within the usable range.
Battery Types and Approximate Voltage
Below is a simple table illustrating common battery types and their typical voltages. Remember to check the specific battery's rating and consider using multiple cells in series to reach the required voltage (6-20V, ideally 7-12V for VIN/power jack).
| Battery Type | Single Cell Voltage (Approx.) | Notes |
|---|---|---|
| Alkaline (AA, AAA) | 1.5V | Use multiple in series for required V |
| NiMH Rechargeable | 1.2V | Use multiple in series for required V |
| Lithium (AA, AAA) | 1.5V | Use multiple in series for required V |
| 9V Alkaline/NiMH | 9V | Single unit, good for low-power |
| LiPo/Li-ion (Single) | 3.7V | Need multiple in series (e.g., 2S = 7.4V) |
Connecting a Battery
You can connect your chosen battery pack or single 9V battery to your Arduino board via:
- The Barrel Power Jack: Use a battery clip or holder with a barrel jack connector. This is the most common and protected method as it uses the board's onboard voltage regulator.
- The VIN Pin: Connect the positive terminal of your battery supply directly to the VIN pin and the negative terminal to GND. Ensure your battery voltage is within the 6-20V range (preferably 7-12V). Be careful not to reverse polarity.
In conclusion, powering an Arduino board with a battery is not only possible but a standard practice for creating portable electronics projects. By selecting a battery that provides the recommended voltage (ideally 7-12V) and connecting it correctly, you can power your Arduino project anywhere.
