XR Battery Status LEDs

Posted: May 23, 2020, Updated: June 13, 2020

This is a list of XR Battery LED Statuses that I’ve encountered, and my best effort at describing the actual causes of them, rather than “you broke it.”

In most cases involving some sort of communication issue, ensuring that the battery connector is secure and cleaning the contacts can help fix some issues.

Abnormal Conditions

LED Pattern LED Description Status Description

Triple blinking Red Power LED, 2nd from top charge LED on Red Light of Death (RLOD) - Fatal Error
This is a permanent* error, indicating a that the BMS (Battery Management System) has detected an error that it can not recover from. This is overwhelmingly caused by cells becoming unbalanced (more than 500mV between the highest and lowest charged cells), but can be caused by other major problems.

See the RLOD FAQ for more information.

Red/yellow alternating power LED, 2nd from top charge LED on Overheating - Possible Issue
One of the battery’s temperature sensors is reading a value that’s too high. Let the battery pack rest, and it will likely clear itself. (Via @ourcore.)

Breathing yellow power LED, middle three charge LEDs on CAN Communication Timeout - Possible Issue
The battery believes that it’s connected to the ESC, but it stopped receiving CAN heartbeats from the ESC.
This can seemingly also happen if the Battery is “on” (charging) for an extended period of time.

Breathing yellow power LED, top charge LED on Charger Problem - Possible Issue
Seen when the charger voltage is too low, or can provide too little current, for the XR BMS to be happy. Charging at less than ~10W seems to cause this, but is probably thrown for any charging issue.

Normal Conditions

LED Pattern LED Description Status Description

Fast breathing blue power LED Bluetooth Pairing In Progress
Bluetooth pairing in progress, either to a phone or remote. Pressing the power button 5 times in a row initiates this mode.

Solid yellow power LED Battery Disconnected
The battery believes that it’s not connected to anything. This is a normal status if you power on the battery when it’s not connected to a board.