DISCOVER ELEMENT - Battery Management System (BMS); BMS Protections Details

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The BMS reconnects when it hits recovery thresholds. Manually switch the battery
module ON if the BMS disconnects due to low voltage protection. A physical
disconnect switch is recommended to reconnect the battery module if the system
has a constant parasitic draw.
After a load qualification fault, there is a 120-second delay until you can switch ON
the battery module again. In other words, if a user switches the battery module OFF
after a load qualification fault, the user cannot switch the battery module ON again
until the 120-second delay is over.
NOTE
• Charge and discharge have different operating temperature limits.
• If the BMS disconnects in response to temperature or current limits, wait for the
temperature or current to reach normal operating limits before switching the battery
module ON.
7.3.2 Battery Management System Pre-Charge System
The battery module has a Pre-Charge System to energize external capacitive loads
before switching the main relay ON, allowing you to connect battery modules at
different SOC. The maximum input capacitance for a single battery module should
not exceed the values in Table 3-1, ELEMENT ESS Electrical Specifications.
NOTICE
When switching ON battery modules, the inrush current may cause the battery
modules to fault as they energize external capacitive loads. If the battery fails to turn
ON, it retries up to 10 times. Verify the cables and connections, then switch ON the
battery modules again.
7.3.3 Battery Management System Load Qualification
When the battery module switches from the OFF state to the ON state, the battery
module BMS will qualify the external load before switching ON the main relay.
Load qualification will reject switching ON into short circuit, reverse polarity, mixed
voltage systems, or capacitive loads that exceed the battery modules limits.
The battery module will attempt Load Qualification a maximum of ten times. After
ten failed attempts at Load Qualification, the battery module switches OFF.
During Load Qualification, or when a load is disqualified, the At-a-glance LED
flashes red.
7.3.4 Battery Management System Cell Balancing
The cell balancing circuits in the battery module compare all cells in a battery
module and balance the cell voltage at the end of the charge. When there is
a network of battery modules over the LYNK port, all battery module cells are
balanced as an entire system, not as individual battery modules.