Wake Up #
For Wakeup:
- Set KL15 (Ignition) to high
- Send VCU_SleepCmd = 0
- Observe BMS_Mode = INITIALIZATION during self-check sequences
- Observe BMS_Mode = READY when system completes self-check sequences succesfully
- Observe BMS_Mode = ERROR or EMERGENCY POWER DOWN if there are faults detected
To go back to INITIALIZATION:
- Send VCU_NormalPowerDownCmd = 1
- Wait a few seconds, Send VCU_SleepCmd = 1
- Wait a few seconds, Send VCU_SleepCmd = 0
Ensure the Link voltage (Load side of the Pack) is discharged below safety limits (< 65 V) before wakeup or else the BMS may forbid closure of the contactors and move to Error mode. Sleep and wakeup cycle may clear this error if Link voltage is below 65V during the self-check sequence.
Should there be a need to disable the isolation, send the disable command only after BMS_mode is in READY MODE or else the BMS cannot finish the self check sequence.
Configuration #
The BMS can be configured for the below features. All configurations are essentially needed once. The configuration is saved in Non Volatile Memory.
1. Disable LED lights #
By default, the LED on the BDU lights up. With the below configuration steps, the LED flashing on the BDU can be changed:
Step 1: Choose the option CAN signal VCU_Cmd.VCU_DisableLED_Cmd: 0(Enable-Default), 1(Disable)
Step 2: Confirm the selection(in step1) CAN signal VCU_Cmd.VCU_SetDisableLED_Cmd: 0(Default),1(Set/confirm)
Step 3: Enter the configuration key CAN signal VCU_Cmd.VCU_ConfigKey. If the configuration key is wrong, the settings will not be applied.
Step 4: Confirm the configuration by reading the CAN signal BMS_Sts.BMS_LEDActiveSts: 0(Enabled),1(Disabled)
Step 5: Clear the VCU_Cmd.VCU_SetDisableLED_Cmd flag
2. Change the Baud Rate #
By Default, the packs are configured to 500Kbps, However it can be changed to 250kbps by following these steps:
Step 1: Choose the baud rate using CAN signal VCU_Cmd. VCU_CAN3_SelectBaudRate: 0(500kbps-default), 1(250kbps)
Step 2: Confirm the selection in Step1 using CAN signal.VCU_CAN3_SetBaudRate : 0(Default/Clear),1(Set/confirm)
Step 3: Enter the configuration key CAN signal VCU_Cmd.VCU_ConfigKey. If the configuration key is wrong, the settings shall not be applied.
It is recommended to use 500kbps when using packs in parallel to avoid high CAN network bus load. For 14 packs, it consumes 70% of the Bus load. Thus, in order to connect more than 14 packs, use another CAN network.
3. Set the Pack ID #
By Default, the single packs are configured with Pack ID as zero and Multi packs are configured with Pack ID as 1 from the factory. However, follow below steps to change the Pack ID:
Step 1: Connect only the desired pack(disconnect other packs) in CAN network for easy configuration
Step 2: If the current pack ID is X, the BMS messages IDs will be 0x18FF41DX, 0x18FF42DX, 0x18FF43DX, 0x18FF44DX, 0x18FF45DX, 0x18FF46DX, 0x18FF47DX, 0x18FF48DX, 0x18FF49DX, 0x18FF4ADX, the corresponding VCU CAN message will be 0x18FFDX5A
Step 3: Choose the pack ID as Y by the CAN signal VCU_Cmd_PackX.VCU_SelectPackID_PackX
Step 4: Confirm the selection in Step 3 by CAN signal VCU_Cmd_PackX.VCU_SelectPackID_PackX: 1(Set/confirm), 0(Clear flag)
Step 5: Enter the configuration key usingCAN signal VCU_Cmd_packX.VCU_ConfigKey_PackX. If the configuration key is wrong, the settings will not be applied.
Step 6: Confirm the Pack ID by CAN signal BMS_Sts_PackY.BMS_MyPackID_PackY is Y.
Step 7: Clear the VCU_Cmd_PackX.VCU_SelectPackID_PackX flag.
Its recommended to have Pack ID=0 for single pack and (0 < Unique Pack ID <=14) in one Multipack CAN network. To connect more than 14 packs, use another CAN network with (0 < Unique Pack ID <=14).
Power Up #
When “BMS_mode = READY” shows up, that means the battery pack is ready to power-up and you can close the contactors.
In parallel pack architecture before commanding Power Up sequence ensure that:
- All packs are in READY mode and there are no ERRORS
- All packs are balanced within 10V. The biggest pack voltage difference between any 2 packs shall not exceed 10V.
- If the power distribution unit (PDU) is equipped with contactors, command the VCU to close them, connecting loads before initiating the power-up sequence.
- Power-up sequence for all the balanced packs is initiated at the same time to reduce pre-charge time.
Requesting Power up of an unbalanced pack will lead to pre-charge sequence failure and risks damaging components.
If PDU contactors are not closed prior to BMS Power up sequence, closing them at a later stage will lead to high in-rush current into the load capacitance. This can cause damage and voids the warranty.
For Power-up:
- Send VCU_NormalPowerUpCmd = 1
- Observe BMS_Mode = OPERATIONAL
Power Up Handshake sequence diagram of an individual pack:
Charging #
To start charging, while BMS is in OPERATIONAL mode:
- Send the VCU_PlugInChrgCmd = 1 and VCU_EndOfChargeCmd = 0
- Observe BMS_Mode = CHARGING
Charging current in this mode is limited by the BMS_MaxChrgCurrChrgr sent by BMS on CAN.
To stop charging:
- Send VCU_EnfOfChargingCmd = 1 and VCU_ PlugInChrgCmd = 0
- Observe BMS_Mode = OPERATIONAL
Start and Stop Charging Handshake Sequence Diagram:
If the actual effective current is more than current limits from the BMS, the battery may malfunction and enter unrecoverable CAT7 system faults.
Enable the charger to source current only after all the balanced packs are in charging mode, otherwise, it may lead to uncontrollable power error, especially at the higher and lower SOC ranges.
Power Down #
Ensure that the current load is removed before commanding power-down operation to the BMS.
Power-Down operation performed under load reduces the contactors life, can cause damage to contactors, and causes high back EMF.
- Send VCU_NormalPowerDownCmd = 1
- Observe BMS_Mode = POWER DOWN
Power-down Handshake Sequence Diagram:
Normal power-down VCU-BMS handshake sequence.
In parallel architecture, initiate the Power-Down sequence of all the packs simultaneously to significantly reduce the power-down procedure time.
Sleep #
For Sleep:
- Send VCU_SleepCmd = 1
- Observe BMS_Mode = SLEEP
The BMS will keep receiving the VCU CAN messages until CAN traffic is live and KL15 line is off. When the CAN traffic is off and KL15 is off, the BMS will go to Low Power mode and stop receiving VCU commands.
