As of February 8, 2023, the now-discontinued LC709203 battery monitor chip has been replaced with the MAX17048. Unsure which one you have? Check the silk on the back of the board. If your board does NOT have "MAX17048 Monitor" in the upper left corner, then you have the LC709203 version.

There are two ways to power your Feather:

1) Power with a USB Cable connected to a power source.

2) Connect a 4.2/3.7V Lithium Polymer (LiPo/LiPoly) or Lithium Ion (LiIon) battery to the JST jack. This lets you run the Feather without wires, untethered! 

If you're running off of a battery, chances are you want to know what the voltage is! That way you can tell when the battery needs recharging. 

In this section, you'll connect a battery to your Feather, and configure a battery monitor component from Adafruit IO to report the board's battery voltage and charge percentage. 

Where is the Battery Monitor on my Feather?

The Feather's  LC709203F LiPoly / LiIon Fuel Gauge and Battery Monitor is located directly above the STEMMA port, highlighted in pink.

Powering the Feather with a Battery

Adafruit highly advises using Adafruit batteries. They have the correct wiring and built in short circuit protection. Batteries from other sources may have incorrect wiring and/or no short protection.

You can plug any 250mAh or larger 3.7/4.2V Lipoly battery into the JST 2-PH port (identified in the diagram below) to power your Feather and charge the battery. The battery will charge from the USB power when USB is plugged in. If the battery is plugged in and USB is plugged in, the Feather will power itself from USB and charge the battery up.

For more information about powering your Feather, visit the Power Management Page in this guide >>>

Add Battery Monitor Component to Adafruit IO

From your device page, click the New Component (or +) button.

From the component picker, select the LC709203F.

On the Create LC709203F Component form, there are two options:

  1. Enabling the battery cell voltage reading will cause the Feather to report the status of its battery expressed in Volts.
  2. Enabling the battery cell percent reading will cause the Feather to report the status of its battery expressed as a percent. 

Then, the battery measurement will be read and sent to Adafruit IO every "Send Every" period.

In the screenshot below, we've configured the battery monitor to report its battery cell voltage and percent to Adafruit IO every 30 seconds.

After configuring the LC709203F component, click Create Component.

Every 30 seconds, the Feather uses the LC709203F component to measure its battery cell percent and voltage, and report it back to Adafruit IO.

Going Further

Now that you have a battery monitor component set up on Adafruit IO, follow this guide to configure Adafruit IO Action for receiving an SMS when your Feather's battery level is below a threshold.

This guide was first published on Nov 25, 2021. It was last updated on Feb 29, 2024.

This page (Monitor Battery (LC709203F)) was last updated on Aug 29, 2023.

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