BYD Battery-Box LV Flex Lite Service Guideline and Checklist Version 1.0 Make sure to always use the latest version of this service document, available at: www.bydbatterybox.com Important: The installation and all other kinds of works or measurements in combination with the Battery-Box Premium are only allowed by professional and qualified electricians. This checklist is a shortened assistance for the Battery-Box and does not replace the original manual, which can be found on www.bydbatterybox.com / www.
Contents 1. GENERAL STEPS ......................................................................................................................3 2. ERROR ANALYSIS.....................................................................................................................4 3. MEASUREMENT....................................................................................................................... 16 4. SERVICE TASKS.............................................................................
1. GENERAL STEPS Make sure to always use the latest version of this service document, available at: www.bydbatterybox.com Please proceed first with the installation steps by: No. Name Description 1.1 Configuration Check if the configuration is correct. Refer to latest “BYD BATTERY-BOX LV Flex Lite MINIMUM CONFIGURATION LIST ”(V1.0 or above) available at: www.bydbatterybox.com Make sure the inverter is configured correctly 1.2 Correct external cabling 1. Communication to inverter a.
BMU for 5 sec). Make sure all LEDs of the battery are completely off. Figure 1 power off BMU Then follow the correct switch on procedure (see step 1.6) 1.6 Switch on procedure Correct switch on procedure is important for a correct operation 1. Turn on the switch between the inverter and battery if there is any; 2. Switch on the battery system; (press LED Button on the LV FLEX Lite module address 1 for 3 seconds; LV FLEX Lite module address 1 is the one connecting directly with BMU). 3.
2.1.3 Voltage Battery voltage should be around 50V, see Section 3.1 for voltage measurement measurement. If yes: try another BMU (if available). If no: check another cable or Try another LV FLEX Lite if multiple batteries are installed in the system. 2.1.4 Only LED faulty? In some rare cases, the LED of the BMU is faulty. To check that: check if there is a Wi-Fi access point of the Battery-Box. If so, only the external LED is inactive and a commissioning could still work. 2.1.
2.2.5 Module Module Exclusion Method (see section 3.2): Check if the system Exclusion works when bypassing the suspected module. Remove it if Method bypassing works. 2.3 Problem with the Firmware Update / App Configuration The Battery Management consists of two components: the BMU and the BMS. The Firmware Update from BC APP and BCP will update the BMU, which will then update the BMS. The BMS update can take up to 30 minutes until the firmware is updated on the BMS. No. Name Description 2.3.
2.3.3 App reports: Battery-Box is busy (e.g. the battery could be updating the “The battery firmware). Please wait 10 minutes and try again. system may be busy, please try again later” 2.3.4 Proper restart Note: Whenever the configuration via BC APP / BCP is changed, a restart of the battery is necessary to make sure that all changes come into effect. 1. Switch off the battery (Press button on BMU for 5 seconds until all batteries switch off.
2.4 Incorrect output voltage / No BMS Data No. Name Description 2.4.1 App Please check if BC APP configuration was successful and the Configuration Firmware is the most recent one. If there are problems, please and Firmware refer to Section 2.3 Note: It is important to select the correct module quantity. The quantity you need to select refers to the overall quantity of LV Flex Lite modules and not to the quantity of towers.
2.4.5 Check terminal Make sure that the terminal resistor is connected to the OUT port resistor (Terminal resistor properties: 120Ω resistor between pin 5 and 6) If it was connected already, then please remove it and try without it to rule out a faulty terminal resistor. Don't forget to properly restart system afterwards. 2.4.6 Module Refer to Section 3.2 to identify a potentially faulty module. Exclusion Method 2.4.7 Further checking If problem remains: - Upload logs with BC APP (section 2.
2.5.5 Further checking If problem remains: - Upload logs with BC APP (section 2.10) or download all data with BCP (section 2.9). - Check the inverter - Try by replacing the BMU, if available 2.6 SOC & charging logic No. Name Description 2.6.1 SOC jumps The SOC of an LFP battery cannot be measured. It is a calculated value. In general, the state of charge (SOC) of a battery is calculated using the voltage, but other factors such as temperature, current flow and charging behavior also play a role.
History Data historic battery log files in order to identify the root cause. See section 2.9 for details. You can also upload logs with BC APP. See section 2.10. 2.7.3 Inverter Warning Unexpected Shutdown can be caused by overall system settings. & Monitoring Therefore, it is necessary to evaluate inverter data as well. - Which error message are shown in inverter portal? 2.8 BMU/BMS LED Event Code (EC) A constant white LED refers to standby mode. White blinking means charge or discharge.
EC 101 / Initialization Failure. - Make sure BC APP-configuration has been completed correctly (especially module quantity!) - Restart the system according to the manual. (Note: to properly shut down you need to press the button on the BMU for 5 seconds. Make sure to start the battery before starting the inverter!) If the problem remains: - Download all data with BCP (especially the historical data) (section 2.9), or upload logs with BC APP (section 2.10).
EC 103 EC 108 PreCharge Fault. - Check DC cabling and make sure that the Minimum Configuration is met. - Restart system properly (see Step 2.4.2, section 2.4; If there is a fuse between battery and inverter, make sure to close the fuse first) - Disconnect the battery system from the inverter and restart the battery system alone (battery isolated), to evaluate if the error is being caused externally (i.e. short circuit in inverter or mppt). If the Event Code remains, the error might be in the battery.
EC 104 EC 102 One of the BMS (modules) reports an event message. up to - Check the voltage of the batteries according to section 3.1 EC113 If problem remains: (All other - Download all data with BCP (especially the historical and the than 101) cell data) (section 2.9), or upload logs with BC APP (section 2.10). - provide the SN and voltage of the faulty module (see checklist at the last ) EC 106 / No communication with Inverter. - Make sure the inverter is on, configured and working correctly.
Figure 3 BCP screenshot 2.10 Upload log data with BC APP When you reach the Status interface, press the three dots on the top left corner, and you will see the menu. Choose Upload Logs, and following the instructions, then you can upload the logs to the BYD server.
3. MEASUREMENT 3.1 Voltage measurement on pin 7&8 Measure the voltage of pin 7 & 8 while the other side of the cable is connected to the IN port of the Battery and while the Battery is powered on. Voltage should be around 50V. Note: Pin 7 and pin 8 are very close. It may cause short circuit if they are measured directly! It is better to take a tool as shown in Figure 5. Option 2 Option 1 Figure 5 voltage measurement on pin 7&8 3.
Note: The affected module often works without restrictions at the lowest module position of the tower. Important: The module quantity must be adjusted in BC APP whenever the number of modules has been changed! Don`t forget to perform a proper restart after a new configuration! 3.3 Undervoltage If the minimum cell voltage is less than 1.5 V, it is in undervoltage (check with BC APP or BCP).
4. SERVICE TASKS Please go through the general steps beforehand, see chapter 1. 4.1 BMU Replacement Have you detected a faulty BMU? After replacing the BMU, please do not forget to re-do the configuration and firmware-update with BC APP or BCP. 4.2 LV Flex Lite Module Replacement After replacing a Module, please do not forget to re-do the configuration and firmware-update in BC APP.
BYD Battery-Box LV Flex Lite Service Checklist - V1.0 EN Important: The installation and all other kinds of works or measurements in combination with the BYD Battery-Box are only allowed by professional and qualified electricians. Improper handling can cause danger and damage. This document does not replace the official BYD manuals and documents. No responsibility is accepted for the accuracy of the information. . 1.
