DJI Issues Firmware Updates For TB50 And TB55 Batteries

Updates Address Small Number Of Batteries Reporting Incorrect Power Levels

November 16, 2018 – New firmware updates are now available for users of TB50 and TB55 batteries to
enhance the battery management system and optimize power supply during flight. DJI implemented this
measure following reports that a small number of TB50 and TB55 batteries have shown incorrect power
levels that have led to the loss of power mid-flight.

This firmware update addresses a rare issue involving the battery state of charge (SOC) calculation
algorithm, and adds the following measures in the flight controller to help bolster flight safety and product
reliability which are DJI’s top priorities:

1. Battery temperature detection before take-off

The battery temperature will have to be 15°C or higher before the aircraft can take off. This is because a
battery with low temperature has a larger internal resistance, which causes lower voltage than in normal
conditions. A battery with low voltage will have a low SOC (state of charge) value.

2. SOC (state of charge) detection before take-off

The voltage of the battery will be used to verify the SOC  value by the DJI algorithm in the new firmware.
This SOC value will be compared to the one calculated by the battery SOC calculation algorithm to
determine if there is a false high SOC reading. If there is a false high SOC reading, then the aircraft will not
be able to take off.

3. Return-to-Home (RTH) or Landing in advance

When the DJI algorithm detects a difference in SOC levels between the algorithm and the actual level that
is greater than 5%, RTH (return-to-home) will be activated at a detected battery level of 30% and
automatic landing activated at 10% (based on the DJI algorithm). If the difference is less than 5% then no
action will be activated.

DJI conducted extensive tests to verify these new measures. All DJI users are strongly urged to
immediately update their firmware to include the latest safety feature improvements, whether through
the flight control app or the DJI Assistant 2 program. Please allow extra time before your next flight to
perform this update. The DJI Pilot app will prompt users to update, and the DJI GO 4 app will not allow flight until the update is performed.

If you believe you may have experienced a related power problem involving the TB50 or TB55 battery,
please contact DJI customer service at dji.com/support to report the issue.