© 2023 by XOLTA
13
Figure 3.2:
Illustration of the
XOLTA Outdoor BESS
BPU front view
Each XOLTA Outdoor BESS has a battery protection unit (BPU). Figure 3.2 is an illustration of the BPU.
The site controller is installed in the BPU and is connected to the XOLTA Cloud using the Ethernet port.
The Ethernet port also ensures communication between neighboring BAT-80 racks when they are operating in
unison. The site controller communicates with Lithium Balance’s n-BMS via the iCAN bus. The site controller also
governs activation of the thermal management system, sensing cell, outdoor air temperature and humidity.
Communication with external energy meters can be realized via Modbus RTU or Modbus TCP communications
protocols:
- If a Modbus RTU meter is used, then it should be connected to the port indicated in Figure 3.2 (otherwise
it should be terminated by an external jumper).
• If a Modbus TCP meter is used, then it should be connected to the external switch (refer to the Installation
procedure section).
The sCAN port is only for internal use during BESS maintenance (Figure 3.2).
The iCAN port is only used for non-standard installations and it should normally be terminated by an external
jumper.
Both Modbus RTU and iCAN buses may be terminated by addition of external jumpers as indicated in Figure
3.2 (depending on the specific installation requirements).
The SPI port is used for communication between the n-BMS Main Control Unit (MCU) and the n-BMS Cell
Monitoring Units (CMUs) that are in battery packs. The BPU is powered by single phase N+PE.
The LED diode presented in Figure 3.2 is a BPU power indicator.
3.3 System safety
3.3.1 Safety measures
The XOLTA Outdoor BESS is protected by Lithium Balance’s state of the art n-BMS. The system
monitors essential parameters of the battery system (cell voltage, current, temperature) to ensure
safe operation. The n-BMS also monitors the battery main parameters, e.g. State of Charge (SoC),
and undertakes battery cell balancing to ensure maximal energy utilization and performance.
The XOLTA Outdoor BESS is equipped with a battery protection unit (BPU) which protects the battery
and the inverter from conditions that can be detrimental to the BESS. It includes redundant contactors
controlled by the n-BMS and redundant fast battery fuses. The state of the contactors is monitored
by the n-BMS.
To assure system longevity and safe operation (maintaining correct operating temperatures), each
of the XOLTA Outdoor BESS battery packs is equipped with four temperature sensors. These give a total
Modbus RTU termination jumper
iCAN termination jumper
RTU A
RTU B
iCAN L
iCAN H
iCAN Shield
sCAN L
sCAN H
LED: ON/OFF
