Arduino is an open-source development platform designed for beginners, hobbyists, teachers, and engineers. Arduino is popular due to its flexibility and ease of use. Arduino provides multiple ways to interact with it, especially when it comes to powering Arduino. Arduino boards can be powered up using three different methods: USB port, DC barrel jack and Vin pin. Here we will discuss how a 9V battery can be used in powering an Arduino.
Can I Connect a 9V Battery to Arduino
Yes, Arduino can be powered up using a 9V battery. There are several ways through which we can power an Arduino board and one is using a 9V external battery. Using a 9V battery we can make the Arduino project portable without any need for an extra power source.
Following are the two ways to connect 9V battery to Arduino:
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- Connect 9V Battery Using Vin Pin of Arduino
- Connect 9V Battery Using DC Barrel Jack of Arduino
1. Connect 9V Battery Using Vin Pin of Arduino
Arduino has an onboard Vin pin, using Vin pin we can connect a 9V battery across Arduino. This Vin pin can work in a dual way. It can either act as a power source for Arduino or can give power to external devices when a power supply is connected across a DC barrel jack. While powering an Arduino with 9V battery using Vin pin it is recommended to check power connections, because Vin pin has no reverse polarity protection.
To power the Arduino using a 9V battery, connect the positive terminal of the battery to Vin pin of Arduino and negative terminal with GND pin of Arduino. Below is the connection diagram of the 9V battery with Arduino.
Vin pin can take maximum of 12V and current up to 800mA:
| Specifications | Value |
| Voltage | 7-12v (+Vcc) |
| Current | Up to 800mA |
2. Connect 9V Battery Using DC Barrel Jack of Arduino
Another way of connecting a 9V battery with Arduino is using a DC barrel jack. DC barrel jack uses on board voltage regulators that can reduce incoming voltages to 5V and 3.3V. In case of batteries DC barrel jack is not that much efficient due to these regulators, most of the voltages are lost in form of heat dissipation.
A 9V battery can be connected using the DC barrel connector that is easily available. While using a DC barrel jack it is recommended to maintain voltage greater than 7V, if the voltage becomes less than this Arduino will not work properly, and the 5V input output pins may end up giving less than 5V which will affect overall circuitry. Below diagram illustrate how can we connect 9V battery with Arduino.
While powering Arduino with 9V battery though DC barrel jack following specifications should be met:
| Specifications | Value |
| Voltage | 7-12v |
| Current | Up to 800mA |
The barrel jack has following requirements for Arduino:
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- Barrel plug must be center positive
- Barrel plug must have internal diameter of 2.1mm and with outer diameter of 5.5mm
- Optimum operating voltages are recommended between 9-12V
- Operating current should not exceed 1A
How Long Does Arduino Last with a 9V Battery
How long an Arduino lasts with a 9V battery completely depends upon the usage of Arduino and external circuitry attached with it. Arduino works over 5V and when we power Arduino using 9V battery Arduino reduces that voltage to 5V first then feeds the internal circuit components.
Problem is with an internal linear regulator that drops 9V to 5V. For instance, if we draw 50mA current through a 9V battery, 0.2W is used by the regulator as heat dissipation and hardly 0.25W is being used by the Arduino board itself, which is overall very inefficient.
Considering all these calculations a 9V battery has approx. The current capacity of 450mAh hardly can last for 3 to 4 days on normal Arduino usage for a whole day. If you need to run an Arduino board on 9V batteries it’s better to go with Arduino boards having less power requirements like Arduino nano and mini.
Conclusion
Batteries are a great way of powering Arduino specially for wireless based projects like weather monitoring or fire alarm systems. Downside to battery usage is they are not that efficient in delivering long term power, one can consider rechargeable batteries if he needs to power Arduino without any external supply. Here we have discussed how to power an Arduino using a 9V battery through the DC jack and Vin pin of Arduino.
