Connections - BMU801

BMU801 Quick Guide
Document code
M212977EN
Revision
A
Language
English
Product
BMU801
Document type
User guide
BMU801 front and bottom connectors
BMU801 connectors
Number in figure BMU801 connector name Purpose
1 Solar 1 9–28 V DC input from solar panel 1 1
2 Solar 2 9–28 V DC input from solar panel 2 1
3 DC in 9–28 V DC input from DC power supply 1
4 Batt 1 Battery 1 connector
6 NTC Temperature sensing resistor (NTC) connector
5 Batt 2 Battery 2 connector
7 I/O Status output
8 DC out

Power output

Nominal output voltage 24 V 2
9 Modbus Data and control interface
  1. Connect the battery cables to the battery connectors Batt 1 and Batt 2.
    If you have only one battery in your system, connect it to Batt 1. Powering up the system when running on battery (only the battery and no DC input connected) requires that the battery is connected to the Batt 1 port.

    Make sure that you connect the battery cable and the corresponding NTC resistor cable to the same battery:

    • Battery cable from BMU801 connector Batt 1 and the NTC cable next to it to the first battery.
    • Battery cable from BMU801 connector Batt 2 and the NTC cable next to it to the second battery (if you have a second battery in the system).
  2. To connect solar panels, connect the first solar panel to Solar 1 and the second solar panel to Solar 2.
  3. To connect a DC power supply, connect a cable from the DC power supply to DC in.
    CAUTION Do not connect too high DC input voltage to the device. If the maximum input voltage is exceeded, the device will stop operating.
    When using external DC power supply, Vaisala recommends to install an external 10 A or 16 A disconnection device for the DC input.
  4. To use the Modbus interface for connecting with Vaisala Data Management Unit DMU801 (or another external host device), connect DMU801 to Modbus.
    When connected, DMU801 receives data from BMU801 and is able to monitor it. In addition, the BMU801 settings are configured in DMU801.
  5. To utilize the I/O interface, use the I/O connector.
    You can use the I/O connection for:
    • Monitoring charging status
    • Indicating errors and fault situations
    • Measuring battery voltage
    • Powering off the system
1 For battery charging, the input voltage must exceed the battery voltage (15 V DC or higher for optimal performance).
2 The actual output equals the DC input voltage, when DC power supply or solar panels are connected. If no DC power or solar power is available, the output equals the battery voltage.