3.6 Battery protection - Movicom Electric Docs

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The BMS Main 2.x board continuously monitors the state of the cells, BMS Logic boards, the external environment and, when detecting abnormalities, protects the battery and system components from damage.

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== 3.6.1 Overcurrent protection ==

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To change the current protection of the battery, select the menu "Protections → Overcurrent protection":

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[[Overcurrent protection settings>>image:1732211959984-118.png||data-xwiki-image-style-alignment="center" height="266" width="386"]]

In this section:

* Enable – a flag to enable the protection;

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* Maximum charging current, А;

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* Tolerant charging current, А;

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* Maximum discharging current, А;

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* Tolerant discharging current, А;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset – a flag to block the error until the board is restarted.

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As a result of operation of the current protection, the "Overcurrent" error is generated.

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Error generation conditions:

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* the current is positive (charging), and its modulo value is greater than the “Maximum charging current” value for the “Delay before setting the error” time;

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* the current is negative (discharging), and its modulo value is greater than the “Maximum discharging current” value for the “Delay before setting the error” time.

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Conditions for removing the error:

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* the current is positive (charging) or zero, and its modulo value is less than the “Tolerant charging current” value for the “Delay before clearing the error” time;

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* the current is negative (discharging), and its modulo value is less than the “Tolerant discharging current” value for the “Delay before clearing the error” time.

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If there is the "Overcurrent" error, the charging and discharging relay open.

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== 3.6.2 Undervoltage protection ==

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The board implements battery protection from too low or too high voltage on the cells.

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To change the battery protection parameters from low voltage on the cells, select the menu "Protections → Undervoltage protection":

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[[Undervoltage protection settings>>image:1732212212350-294.png||data-xwiki-image-style-alignment="center" height="207" width="359"]]

In this section:

* Enable – a flag to enable the protection;

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* Minimum cell voltage, V;

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* Tolerant cell voltage, V;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of battery protection from low voltage, the "Undervoltage" error is generated.

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Error generation conditions:

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* the minimum voltage among all cells of the battery is less than the “Minimum cell voltage” value for the “Delay before setting the error” time.

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Conditions for removing the error:

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* the minimum voltage among all cells of the battery is greater than the “Tolerant cell voltage” value for the “Delay before clearing the error” time.

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If there is the "Undervoltage" error, the discharging relay opens.

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3.6.3 Overvoltage protection

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To change the battery protection parameters from high voltage on the cells, select the menu "Protections → Overvoltage protection":

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[[image:1732212357972-295.png]]

In this section:

* Enable – a flag to enable the protection;

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* Maximum cell voltage, V;

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* Tolerant cell voltage, V;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Switch off the discharging relay on error – a flag to open the discharging relay when the "Overvoltage" error is generated;

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* Lock the error until the device is reset.

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As a result of the operation of the battery protection from high voltage, the "Overvoltage" error is generated.

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Error generation conditions:

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* the maximum voltage among all cells of the battery is greater than the “Maximum cell voltage” value for the “Delay before setting the error” time.

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Conditions for removing the error:

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* the maximum voltage among all cells of the battery is less than the “Tolerant cell voltage” value for the “Delay before clearing the error” time.

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If there is the "Overvoltage" error, the charging relay and discharging relay opens (if the “Switch off the discharging relay on error” flag is set).

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== 3.6.4 Low temperature protection ==

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The board implements battery protection from too low temperature.

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To change the battery protection parameters from low temperature, select the menu "Protections → Low temperature protection":

In this section:

* Enable – a flag to enable the protection;

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* Minimum charging temperature, °C;

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* Tolerant charging temperature, °C;

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* Minimum discharging temperature, °C;

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* Tolerant discharging temperature, °C;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of the battery protection from low temperature, the "Low CH temperature" or “Low DCH temperature” error is generated.

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Error generation conditions:

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* the minimum temperature among all cells of the battery is less than the “Minimum charging (discharging) temperature” value for the “Delay before setting the error” time.

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Conditions for removing the error:

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* the minimum temperature among all cells of the battery is greater than the “Tolerant charging (discharging) temperature” value for the “Delay before clearing the error” time.

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If there is the "Low CH temperature" error, the charging relay opens.

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If there is the "Low DCH temperature" error, the discharging relay opens.

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== 3.6.5 High temperature protection ==

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The board implements battery protection from too high temperature.

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To change the battery protection parameters from high temperature, select the menu "Protections → High temperature protection":

In this section:

* Enable – a flag to enable the protection;

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* Maximum charging temperature, °C;

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* Tolerant charging temperature, °C;

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* Maximum discharging temperature, °C;

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* Tolerant discharging temperature, °C;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of the battery protection from high temperature, the "High CH temperature" or “High DCH temperature” error is generated.

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Error generation conditions:

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* the maximum temperature among all cells of the battery is greater than the “Maximum charging (discharging) temperature” value for the “Delay before setting the error” time.

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Conditions for removing the error:

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* the maximum temperature among all cells of the battery is less than the “Tolerant charging (discharging) temperature” value for the “Delay before clearing the error” time.

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If there is the "High CH temperature" error, the charging relay opens.

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If there is the "High DCH temperature" error, the discharging relay opens.

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== 3.6.6 Battery cover protection ==

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To change the protection parameters from opening the battery cover, select the menu "Protections → Battery cover protection":

In this section:

* Enable – a flag to enable the protection;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of the protection against opening the battery cover, the “Battery cover error” is generated.

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Error generation conditions:

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* there is a signal from the battery cover during the “Delay before setting the error” time.

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Conditions for removing the error:

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* no signal from the battery cover during the “Delay before clearing the error” time.

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**If there is the "Battery cover error", the “Critical error” is generated and all relays open.**

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== 3.6.7 High humidity protection ==

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The board can protect the battery from high humidity and water.

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To change the protection parameters of the battery from high humidity, select the menu "Protections → High humidity protection":

In this section:

* Enable – a flag to enable the protection;

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* Maximum humidty, RH%;

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* Tolerant humidty, RH%;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of the battery protection from high humidity, the "High humidity" error is generated.

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Error generation conditions:

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* the measured humidity is greater than “Maximum humidity” during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the measured humidity is less than the “Tolerant humidity” during the “Delay before clearing the error” time.

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If there is the "High humidity" error, no action is taken. The error is indicative.

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== 3.6.8 Water protection ==

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To change the protection parameters of the battery from water, select the menu "Protections → Water protection":

In this section:

* Enable – a flag to enable the protection;

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* Maximum (water) humidty, RH%;

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* Tolerant humidity, RH%;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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As a result of the operation of the battery protection from water, the "Water" error is generated.

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Error generation conditions:

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* the measured humidity is greater than the “Maximum (water) humidity” value during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the measured humidity is less than the “Tolerant humidity” value during the “Delay before clearing the error” time.

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**If there is the “Water” error, the “Critical error” is generated and all relays open.**

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== 3.6.9 Current sensor error ==

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The board is implemented to check the current sensor connection circuits. The circuits are checked for breakage and short-circuit to the +5 V supply line.

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To change the test parameters of the current sensor connection circuits, select the menu "Protections → Current sensor error":

In this section:

* Enable – a flag to enable the protection;

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* Maximum voltage, V;

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* Minimum voltage, V;

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* Hysteresis voltage – a hysteresis value to clear the error, V;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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If there is an open or short circuit connection of a current sensor, the "Current sensor error" is generated.

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Error generation conditions:

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* the voltage in the signal line or zero level line of the current sensor is greater than the “Maximum voltage” value during the “Delay before setting the error” time;

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* the voltage in the signal line or zero level line of the current sensor is less than the “Minimum voltage” value during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the voltage in the signal line or zero level line of the current sensor is in range from (Minimum voltage + Hysteresis voltage) to (Maximum voltage - Hysteresis voltage) during the “Delay before clearing the error” time.

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**If there is the “Current sensor error”, the “Critical error” is generated and all relays open.**

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== 3.6.10 Short circuit protection ==

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The BMS implements a protection of power circuits (contactors, power cables) against overheating caused by the flow of high current for a long time.

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To change the protection parameters from short circuit, select the menu "Protections → Short circuit protection":

In this section:

* Level 1, 2, 3 – three protection levels. The following parameters are configured at each level:

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** Enable – a flag to enable the protection;

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** Maximum current, A;

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** Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Switch off the charging relay on error – a flag to open the charging relay when the "Short circuit" error occurs;

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* Switch off the discharging relay on error – a flag to open the discharging relay when the "Short circuit" error occurs;

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* Lock the error until the device is reset.

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If there is a short circuit, the "Short circuit" error is generated.

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Error generation conditions:

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* at any of the three protection levels, the current modulo is greater than the “Maximum current” value during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the current modulo is lower than the “Maximum current” values for all three protection levels during the “Delay before setting the error” time.

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If there is the "Short circuit" error, the charging relay opens (the “Switch off the charging relay on error” flag is set) and the discharging relay opens (the “Switch off the discharging relay on error flag” is set).

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== 3.6.11 Contactor high temperature protection ==

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The BMS protects power contactors from overheating. To measure the temperature of the contactor, a thermistor is used, connected to the P13 connector of the board. Configuring of the analog input for temperature measurement is described in section Input signals.

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To change the overheating protection parameters of power contactors, select the menu "Protections → Contactor high temperature protection":

In this section:

* Enable – a flag to enable the protection;

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* Maximum temperature, °C;

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* Tolerant temperature, °C;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Switch off the charging relay on error – a flag to open the charging relay when the "Contactor high temperature" error occurs;

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* Switch off the discharging relay on error – a flag to open the discharging relay when the "Contactor high temperature" error occurs;

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* Lock the error until the device is reset.

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If there is a contactor overheat, the "Contactor high temperature" error is generated.

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Error generation conditions:

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* the contactor temperature is greater than the “Maximum temperature” value during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the contactor temperature is lower than the “Tolerant temperature” value during the “Delay before clearing the error” time.

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If there is the "Contactor high temperature" error, the charging relay opens (the “Switch off the charging relay on error” flag is set) and the discharging relay opens (the “Switch off the discharging relay on error flag” is set).

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== 3.6.12 Unallowable charging protection ==

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The BMS can detect that the battery is charging through the discharging circuit and protectively open the discharging relay to prevent unallowable battery operation.

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To change the parameters of the unallowable charging protection, select the menu "Protections → Unallowable charging protection":

In this section:

* Enable – a flag to enable the protection;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset.

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If there is charging the battery through the discharging circuit detected, the "Unallowable charging" error is generated.

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Error generation conditions:

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* the charging relay is open and the battery current is not zero during the “Delay before setting the error” time.

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Conditions for removing the error:

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* the battery current is zero during the “Delay before clearing the error” time.

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If there is the "Unallowable charging" error, the discharging relay opens.

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== 3.6.13 Stuck contactor protection ==

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The BMS Main 2.x protects contactors against sticking.

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To change the protection parameters against sticking, select the menu "Protections → Stuck contactor protection":

In this section:

* Enable – a flag to enable the protection;

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* Delay before setting the error, second;

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* Delay before clearing the error, second;

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* Lock the error until the device is reset;

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If there is a stuck contactor, the “Stuck contactor” error is generated.

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Error generation conditions:

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* charging and discharging contactors are open, but the “Charging current present” or “Discharging current present” signal is set.

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== 3.6.14 Contactor feedback check ==

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The BMS Main 2.x can receive feedback signals from contactors and detect discrepancy between the control value and the feedback signal. To enable specific contactor protection, one of the discrete input must be set as corresponding contactor feedback signal (see section Input and output signals).

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To change the contactor feedback check parameters, select the menu "Protections → Contactor feedback check":

In this section:

* Enable – a flag to enable the protection;

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* Delay before setting the error, second;