2. Installation and connection

Last modified by Admin on 2025/03/18 12:50

Installation and connection

Safety rules

To perform the protection functions, the BMS must be able to disconnect the battery from the load and charger. To do this, at least one contactor able to break the load and charge circuits must be connected to the BMS.

Before use, configure the system. Proper operation of the BMS is possible only if it is correctly configured.

It is not recommended to use the system in batteries formed by several series of cells connected in parallel. To increase capacity, it is recommended to connect several cells in parallel groups, and then connect the groups in series.

The BMS can be connected to batteries with life-threatening and health-hazardous voltage levels. When working with high-voltage batteries, observe electrical safety regulations, use safety glasses, protective clothing, insulated tools and appliances. To prevent the damage of device avoid electrostatic discharges while working with the battery.

The system is not designed to operate with batteries whose total voltage exceeds 80V.

Installation procedure

The mounting area of the BMS Mini must be protected from mechanical particles (dust, dirt, large objects) and water. The BMS Mini is recommended to be placed close to the cells it controls, but away from high current circuits to reduce interference to measuring circuits and increase overall reliability of installation.

The installation site must provide convenient access for subsequent connection to the device’s headers for connecting other system elements: a current sensor, contactors, display panels.

The BMS Mini has a heat sink to dissipate the heat generated during the balancing of the cells. When used in enclosed enclosures, heat must be removed from the sink, otherwise it may damage the device.

Overall and mounting dimensions of the BMS Mini are shown on figures below.

Parameter	Value
Overall dimensions (length × width × height), mm	139.5 × 117 × 17
Mounting dimensions (length × width), mm	130 × 111
Mounting holes	M3

Headers

There are names and locations of the BMS Mini headers on figure below.

Х1 – header for contactors

Receptacle Housing: Molex 430251800. Terminals: Molex 43030

Pin	Name	Description
1	-	-
2	+12V	Supply voltage from the internal 12V DC/DC converter
3	GND	Ground
4	+12V	Supply voltage from the internal 12V DC/DC converter
5	GND	Ground
6	+12V	Supply voltage from the internal 12V DC/DC converter
7	GND	Ground
8	+12V	Supply voltage from the internal 12V DC/DC converter
9	GND	Ground
10	-	-
11	FB1	Feedback signal from contactor 1
12	OUT1	Contactor control 1 (low side switch), 100V, max 5A
13	FB2	Feedback signal from contactor 2
14	OUT2	Contactor control 2 (low side switch), 100V, max 5A
15	FB3	Feedback signal from contactor 3
16	OUT3	Contactor control 3 (low side switch), 100V, max 5A
17	FB4	Feedback signal from contactor 4
18	OUT4	Contactor control 4 (low side switch), 100V, max 5A

ATTENTION!!!
The load should be connected to +12V and OUTx pins. The feedback signal should be connected to FBx and GND pins. Below is an example of connecting the BMS to a contactor:

X2 – mini-USB connector.

Mini-USB connector is used for configuring the BMS via ElectricDeviceMonitor.

X3 – header for discrete inputs and outputs signals

Receptacle Housing: Molex 430251600. Terminals: Molex 43030

Pin	Name	Description
1	DIN1	Discrete input 1 “dry contact” (+5V)
2	DIN2	Discrete input 2 “dry contact” (+5V)
3	DIN3	Discrete input 3 “dry contact” (+5V)
4	DIN4	Discrete input 4 “dry contact” (+5V)
5	DOUT1	Discrete output 1 (+5V, 20mA)
6	DOUT2	Discrete output 2 (+5V, 20mA)
7	DOUT3	Discrete output 3 (+5V, 20mA)
8	DOUT4	Discrete output 4 (+5V, 20mA)
9	GND	Discrete input 1 “dry contact” (ground)
10	GND	Discrete input 2 “dry contact” (ground)
11	GND	Discrete input 3 “dry contact” (ground)
12	GND	Discrete input 4 “dry contact” (ground)
13	GND	Discrete output 1 (ground)
14	GND	Discrete output 2 (ground)
15	GND	Discrete output 3 (ground)
16	GND	Discrete output 4 (ground)

Х4 – header for САN and RS485 interfaces

Receptacle Housing: Molex 430250600. Terminals: Molex 43030

Pin	Name	Description
1	RS485_B	RS485 line B
2	+5V	Isolated supply voltage 5V, max 400mA
3	CAN_L	CAN-L line of the CAN bus
4	RS485_A	RS485 line A
5	GND	Isolated ground
6	CAN_H	CAN-H line of the CAN bus

Х5 – header for ON/OFF button

Receptacle Housing: Molex 430250200. Terminals: Molex 43030

Pin	Name	Description
1	BTN	Signal to turn on/off the BMS (“dry contact”, +3.3V)
2	GND	Signal to turn on/off the BMS (“dry contact”, ground)

X6 – header for cells temperature sensors

Receptacle Housing: Molex 430251200. Terminals: Molex 43030

Pin	Name	Description
1	TEMPG1	Ground of the thermistor 1
2	TEMPG2	Ground of the thermistor 2
3	TEMPG3	Ground of the thermistor 3
4	TEMPG4	Ground of the thermistor 4
5	TEMPG5	Ground of the thermistor 5
6	TEMPG6	Ground of the thermistor 6
7	TEMP1	Signal from the thermistor 1
8	TEMP2	Signal from the thermistor 2
9	TEMP3	Signal from the thermistor 3
10	TEMP4	Signal from the thermistor 4
11	TEMP5	Signal from the thermistor 5
12	TEMP6	Signal from the thermistor 6

X7 - header for current sensor

Receptacle Housing: Molex 430250400. Terminals: Molex 43030

Pin	Name	Description
1	+5V	Supply voltage for a current sensor 5V, max 50 mA
2	GND	Ground
3	Vcs	ADC input (current sensor output)
4	Vref	Auxiliary ADC input (current sensor reference signal)

Х8 – header for battery cells

Receptacle Housing: Molex 430252000. Terminals: Molex 43030

Pin	Name	Description
1	C0	Minus of the cell stack (for measuring purposes only)
2	C2	Cell 2
3	C4	Cell 4
4	C6	Cell 6
5	C8	Cell 8
6	C10	Cell 10
7	C12	Cell 12
8	C14	Cell 14
9	C16	Cell 16
10	C18	Cell 18 (maximum potential of the cell stack, for measuring purposes only)
11	NC	Not connected
12	C1	Cell 1 (minimum potential with respect to C0)
13	C3	Cell 3
14	C5	Cell 5
15	C7	Cell 7
16	C9	Cell 9
17	C11	Cell 11
18	C13	Cell 13
19	C15	Cell 15
20	C17	Cell 17

Х9 – header to power the device

Receptacle Housing: Molex 436450200. Terminals: Molex 43030

Pin	Name	Description
1	VBAT+	Supply voltage for BMS Mini
2	VBAT-	BMS Mini power ground

Attention! The BMS Mini device is galvanically connected to the battery (the minus of the battery is the device ground). In view of this, when a BMS Wi-Fi or BMS GSM module is connected to the device, the antenna braid will also be galvanically connected to the battery (connected to the battery negative). It is recommended to isolate the antenna cable from the battery case to prevent negative potential from appearing on the case.

J1 – jumper for switching CAN bus terminal resistor

To connect the terminal resistor between the CAN_H and CAN_L lines, install the jumper J1 according to the following figure:

J2 – jumper for switching RS-485 terminal resistor

To connect the terminal resistor between the RS485_A and RS485_B lines, install the jumper J1 according to the following figure:

Connection procedure

Connecting battery cells

To connect battery cells, follow figure below. Incorrect connection of the cells can damage the BMS Mini.

Begin the connection with the negative line of the battery: the “C0“ is connected to the “B-“, then the first cell (C1) is connected, then the second (С2), etc. If not all inputs of the cells are used, then the remaining inputs are connected to the cell with the most potential.

Attention!
Connect the battery according to the diagram, otherwise the device may be damaged.

Connecting thermistors

Thermistors should be fastened to the cells, excluding short circuits to the cell terminals (for example, isolate thermistors with heat shrink).