Battery Voltage Callouts & Low Voltage Voice Alerts on EdgeTX (Complete Setup Guide)

One of the most useful features you can add to your complete FPV drone setup is battery voltage voice alerts. Instead of constantly checking your OSD—or worse, flying without voltage feedback— FPV radio controller can simply tell you the voltage with a switch press or even warn you automatically when it is too low. Learning how to configure battery voltage callouts low voltage voice alerts on edgetx transforms your flying experience by keeping your attention where it belongs: on the drone. In this complete guide by Mall of Aviation, you will learn how to set up both manual voltage callouts and automatic low voltage warnings on any EdgeTX radio, step by step.

Why Use Battery Voltage Voice Callouts?

Monitoring battery voltage is absolutely critical in FPV flying. Proper battery voltage callouts low voltage voice alerts on edgetx help you:

• Prevent over-discharging FPV LiPo batteries: Running a LiPo below 3.0V per cell can permanently damage it, reducing capacity and increasing internal resistance.
• Improve flight safety: A sudden voltage sag at low altitude can lead to failsafes or crashes. Voice alerts give you early warning.
• Maintain battery lifespan: Consistently landing at 3.5V to 3.6V per cell extends battery life significantly.

But in real flight, challenges arise:

• You may forget to check the OSD during intense flying.
• You may be too focused on a tricky line or race gate.
• You may not have an OSD at all (like when flying line of sight).

Prerequisites for EdgeTX Voltage Alerts

Before setting up battery voltage callouts low voltage voice alerts on edgetx, ensure you have the following:

• Your radio runs EdgeTX firmware. Most modern radios like Radiomaster TX16S, Boxer, Zorro, and Jumper T-Pro can run EdgeTX.
• Your drone supports telemetry. ExpressLRS receivers and Ghost all provide telemetry data back to the radio.
• Telemetry is enabled in Betaflight. This allows your flight controller to send battery voltage data through your receiver.
• Your receiver is bound and connected. A solid green LED on your receiver indicates a good link with telemetry.

Step 1: Enable Telemetry in Betaflight

The first technical step for battery voltage callouts low voltage voice alerts on edgetx is enabling telemetry on your flight controller. Follow these steps:

1. Open Betaflight firmware setup and connect your flight controller.
2. Navigate to the Receiver tab.
3. Find the Telemetry section and enable it.
4. Click Save and Reboot.

If you are using ExpressLRS, also ensure that your receiver is configured to output telemetry. Most ELRS receivers do this by default, but double-check your settings if you are not seeing telemetry data on your radio.

Step 2: Discover Telemetry Sensors on EdgeTX

Once telemetry is enabled on your drone, you need to discover the sensors on your EdgeTX radio. This is a crucial part of battery voltage callouts low voltage voice alerts on edgetx setup.

1. Power on your drone and radio, ensuring they are bound.
2. On your EdgeTX radio, navigate to Model Settings (long press MENU, then go to the model page).
3. Scroll to the Telemetry page.
4. Select Discover New sensors.
5. Wait 10 to 15 seconds while your radio scans for telemetry data.
6. You should see a list of sensors appear. Look for RxBt (battery voltage).

If RxBt does not appear, check your receiver telemetry settings and ensure your drone is powered by a battery (not just USB). Some receivers require battery power to transmit telemetry.

Step 3: Verify Voltage Accuracy

Before relying on battery voltage callouts low voltage voice alerts on edgetx, you must verify that the RxBt sensor is reading correctly. Inaccurate voltage readings defeat the purpose of the setup.

To verify:

1. Use a digital multimeter or a LiPo voltage checker to measure your battery voltage directly.
2. Compare this reading with the RxBt value displayed on your EdgeTX telemetry screen.
3. If they match within 0.1V to 0.2V, your setup is accurate.

If the RxBt reading is off, you can calibrate in Betaflight:

1. Go to the Power & Battery tab.
2. Adjust the Voltage Meter Scale until the displayed voltage matches your multimeter reading.
3. Save and reboot.

Step 4: Manual Voltage Callout Using a Switch

Now for the core of battery voltage callouts low voltage voice alerts on edgetx: assigning a switch to instantly announce the battery voltage. This gives you on-demand information without taking your eyes off the drone.

To set up a manual voltage callout:

1. On your EdgeTX radio, go to Model Settings → Special Functions.
2. Scroll to an empty line and press ENTER to edit.
3. Set Switch to your preferred momentary switch (commonly SH or a push button).
4. Set Function to Play Value.
5. Set Parameter to RxBt (battery voltage).
6. Enable the function (checkmark).

Now, whenever you press that switch, your radio will speak the current battery voltage. For example: “22.8 volts” for a 6S battery.

This manual callout is the foundation of battery voltage callouts low voltage voice alerts on edgetx. It gives you immediate, hands-free awareness of your battery status.

Bonus: Per-Cell Voltage Reporting

To make battery voltage callouts low voltage voice alerts on edgetx even more intuitive, you can configure your radio to report per-cell voltage instead of total pack voltage. This is especially useful for understanding battery health at a glance.

In Betaflight CLI, enter:

set report_cell_voltage = on
save

Now, when you use your voltage callout, the radio will report something like “3.8 volts” per cell instead of the total pack voltage. For a 6S pack, you will hear the average cell voltage, which is easier to interpret during flight.

Step 5: Create Logical Switch for Low Voltage Detection

While manual callouts are useful, the true power of battery voltage callouts low voltage voice alerts on edgetx comes from automatic warnings. To set this up, you first need to create a logical switch that detects low voltage.

1. Go to Model Settings → Logical Switches.
2. Find an empty line and press ENTER to edit.
3. Set Function to a<x (a is less than x).
4. Set V1 to RxBt (battery voltage).
5. Set V2 to your low voltage threshold. For per-cell reporting, use 3.5V per cell. For total pack voltage, multiply by the number of cells (e.g., 14.0V for 4S).
6. Set Delay to 3 seconds to prevent false alerts from voltage sag during punch-outs.
7. Name the logical switch (e.g., L01).

This logical switch will become true whenever the battery voltage drops below your threshold and stays there for at least 3 seconds.

Step 6: Automatic Low Voltage Warning

Now that you have a logical switch detecting low voltage, you can create the automatic voice alert. This completes the automated side of battery voltage callouts low voltage voice alerts on edgetx.

1. Go to Model Settings → Special Functions.
2. Find an empty line and press ENTER to edit.
3. Set Switch to your logical switch (e.g., L01).
4. Set Function to Play Value.
5. Set Parameter to RxBt.
6. Set Repeat to 10s (optional) to have the warning repeat every 10 seconds while voltage remains low.

Now, whenever your battery voltage drops below your threshold and stays there, your radio will automatically announce the voltage. You will hear something like “14.2 volts” followed by the repeating alert until you land.

Pro Tips for Better Battery Voltage Alerts

• Use a momentary switch for quick checks: Assign your manual callout to a momentary switch like SH. This lets you get instant voltage feedback without toggling any permanent switches.
• Enable per-cell voltage reporting: The Betaflight CLI command set report_cell_voltage = on makes voltage callouts much easier to interpret, especially for beginners.
• Set a delay on your logical switch: A 2 to 3 second delay prevents false alerts from momentary voltage sags during throttle punches.
• Test your setup before flight: Power up your drone on the bench and simulate low voltage by lowering the threshold temporarily. Ensure the alerts trigger correctly.
• Use both manual and automatic alerts: Manual callouts give you on-demand information, while automatic alerts ensure you never miss a low battery situation.
• Customize voice files: EdgeTX allows custom voice packs. You can create personalized alerts like “Battery low, time to land” for more intuitive warnings.
• Monitor voltage under load vs. resting voltage: Learn to interpret voltage sag. A battery may read 3.8V resting but drop to 3.5V under load. Set your threshold based on loaded voltage for your flying style.

Frequently Asked Questions About EdgeTX Voltage Alerts

Final Thoughts: Never Fly Without Voltage Alerts

Setting up battery voltage callouts low voltage voice alerts on edgetx is one of the simplest yet most powerful upgrades you can add to your FPV setup. It improves safety, protects your batteries from over-discharge, and lets you focus entirely on flying instead of constantly checking your OSD.

With manual callouts on a switch, you can get instant voltage feedback anytime. With automatic low voltage warnings, your radio becomes your co-pilot, alerting you when it is time to land. Together, these features ensure you always land with healthy batteries and avoid unexpected power loss mid-flight.

The setup process takes only a few minutes, but the benefits last for every flight you ever take. Once you have battery voice alerts configured, you will wonder how you ever flew without them.

At Mall of Aviation, we are dedicated to helping FPV pilots fly smarter, safer, and better. Whether you are building your first drone or fine-tuning your tenth, we have the guides and gear you need. Fly safe, and let your radio keep you informed.