RadioMaster ERS-CU01 - Real-Time Current Sensor for Compatible ExpressLRS PWM Receivers

The ERS-CU01 Current Sensor is a compact telemetry module for use with compatible ExpressLRS  receivers. Installed inline between the battery and ESC, it measures real-time operating current and voltage sending the data through the ExpressLRSreceiver for display on your EdgeTX radio. This provides instant insight into system load, efficiency, and power consumption across your entire powertrain.

As part of the ERS sensor family, the ERS-CU01 also supports pass-through expansion, allowing easy daisy-chaining with additional telemetry modules. 

Features

• Real-Time Current Monitoring: View live current draw and voltage directly on your radio to better understand system performance and prevent overload conditions.
• Inline Installation: Soldered between the battery and ESC for accurate, full-system current measurement.
• Future-Ready Pass-Through: Includes in-and-out ports for daisy-chaining additional ERS sensors as your telemetry needs grow.
• Seamless ExpressLRS Integration: Designed to work smoothly with compatible ExpressLRS PWM receivers.

• ER6 2.4GHz ExpressLRSPWM Receiver
• ER8 2.4GHz ExpressLRSPWM Receiver
• ER8G & ER8GV ExpressLRS PWM Receiver

Most PWM ExpressLRS receivers are fully compatible; those without a dedicated UART port require reconfiguration to support external sensors (e.g., for telemetry). To enable this, reassign two PWM output pins as a serial UART—one for TX and one for RX—via the receiver's Web UI (accessed by putting the receiver into WiFi mode) or via the ExpressLRS LUA script. This enables sensor connectivity while preserving the remaining PWM channels for servos or ESCs.

For receivers that only provide standard servo pins, an optional adapter cable is available that converts the sensor’s UART connector to two standard servo plugs (TX and RX). 

Sensor Configuration & Telemetry Logging

To configure this sensor and view telemetry on your EdgeTX radio, install the RadioMaster Sensor Configurator LUA. The LUA allows adjustment of sensor settings, enables proper telemetry display, and supports data logging for post-flight review.

After downloading, connect your radio to a Mac or PC in USB-SD mode.

Copy the LUA files to:
/SCRIPTS/TOOLS/

👉Download the RadioMaster ERS Sensors Configurator.lua

*Battery Capacity must be set in mAh for telemetry

Specifications

• Item: ERS-CU01 Current Sensor
• Operating voltage: 5–8.4V
• Operating current: 22mA
• Current range: 1–150A
• Max voltage: 70V
• Current accuracy: ±0.5A
• Voltage accuracy: ±0.1V
• Continuous current: 100A
• Temperature range: –10 ℃ to +85 ℃
• Size: 30 × 25 × 10.5mm
• Weight: 20.6g

Download

• ERS-CU01 User Manual
• RadioMaster ERS Sensors Configurator.lua
• ERS Series Sensors Firmware V1.3

Size

Weight

Package Includes

• 1 * ERS-CU01 Current Sensor
• 3 * Heat-Shrinkable Tube
• 1 * Manual QR Code Card