In order to install external current sensor connect it to LIN / CAN Bus connector. If direct connection
is not possible, a LIN / CAN Bus splitter should be used in order to interconnect additional bus
node.
3.1.3
Temperature measurement
External temperature sensors are able to measure temperatures from -40
°
C up to 150
°
C. Mea-
surements are performed 2 times a second (
T
= 0
.
5
s
). There are also several internal temperature
sensors that measure temperature of internal device components. All of them are stationary and
cannot be disconnected or altered.
Real time external and internal temperature readings can be found in Status page
→
Battery tab.
Temperature readings are split in to two separate charts. Each chart displays aggregated minimum,
maximum and average values of temperature.
3.2
State of Battery
3.2.1
Charge estimation
State of Charge estimation in EMUS BMS mini is mainly based on the coulomb counting technique.
The coulomb counting is done in sync with the current update process every newly determined
momentary current value is multiplied by the update period, and the result, is accumulated as
Battery Charge value (in Ah). This value is later compared to ”Capacity” configuration parameter
value in order to determinethe SoC expressed in percentage.
3.2.2
Health estimation
TBD
3.3
Charging process
BMS controls charging process and regulates output current of the charging device according to
feedback of measured battery parameters. It ensures that the battery is charged safely and the
battery cell voltages are correctly balanced after the charging process is finished. Regardless of the
charging device type, charging process is divided into six stages:
1.
"Pre-Heating" stage
is entered when the minimum temperature value of all system temper-
ature sensors is lower than the value of "Minimum Charging Temperature" parameter, meaning
that the battery is too cold to be safely charged. Therefore during this stage BMS attempts
to warm it up by activating "Heater" function which can be enabled using pin functions. This
function is indended for switching third-party heating devices on and off.
2.
"Pre-Charging" stage
is entered then the minimum cell voltage is lower then Pre-Charge
Threshold" parameter value. This condition is met only when the battery cell is deeply dis-
charged, therefore during this stage the battery is charged with a reduced current in order to
avoid heat development inside the battery cells due to their increased internal resistance.
3.
"Charging" stage
is entered if the maximum battery cell voltage is less than "Maximum
Cell Voltage" parameter value and no other stage conditions are met. This indicates that no
special precautions are needed in order to safely charge the battery, therefore during this stage
the battery is charged with the highest possible current. Highest current depend on charging
device and Maximum Charging Current" parameter value.
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