Vertiv BAU48/4 User manual

BAU48/4
Battery Asymmetry Unit
Installation and User Manual
Specification Number: 541649
Model Number: BAU48/4

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
The information contained in this document is subject to change without
notice and may not be suitable for all applications. While every precaution has
been taken to ensure the accuracy and completeness of this document, Vertiv
assumes no responsibility and disclaims all liability for damages resulting from
use of this information or for any errors or omissions. Refer to other local
practices or building codes as applicable for the correct methods, tools, and
materials to be used in performing procedures not specifically described in
this document.
The products covered by this instruction manual are manufactured and/or
sold by Vertiv. This document is the property of Vertiv and contains
confidential and proprietary information owned by Vertiv. Any copying, use or
disclosure of it without the written permission of Vertiv is strictly prohibited.
Names of companies and products are trademarks or registered trademarks of
the respective companies. Any questions regarding usage of trademark
names should be directed to the original manufacturer.
Technical Support Site
If you encounter any installation or operational issues with your product, check the pertinent section of this
manual to see if the issue can be resolved by following outlined procedures.
Visit https://www.vertiv.com/en-us/support/ for additional assistance.

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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iii
TABLE OF CONTENTS
Admonishments Used in this Document.............................................................................................................................iv
Important Safety Instructions..................................................................................................................................................v
Safety Admonishments Definitions ..........................................................................................................................................................................................................................v
Safety and Regulatory Statements...........................................................................................................................................................................................................................v
Déclarations de Sécurité et de Réglementation...........................................................................................................................................................................................v
1Description ................................................................................................................................................................................1
1.1 BAU48/4 Battery Asymmetry Unit ................................................................................................................................................................................................................1
2Installing the BAU48/4..........................................................................................................................................................1
2.1 Planned Installation Area........................................................................................................................................................................................................................................1
2.1.1 Fastening the Battery Asymmetry Unit ..............................................................................................................................................................................1
3Making Electrical Connections .........................................................................................................................................3
3.1 Important Safety Instructions............................................................................................................................................................................................................................3
3.2 Wiring Considerations...............................................................................................................................................................................................................................................4
4Operation ..................................................................................................................................................................................5
5Technical Data ........................................................................................................................................................................7
6Troubleshooting and Repair ..............................................................................................................................................8
6.1 Contact Information....................................................................................................................................................................................................................................................8

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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iv
Admonishments Used in this Document
DANGER!
Warns of a hazard the reader will be exposed to that will likely result
in death or serious injury if not avoided. (ANSI, OSHA)
WARNING!
Warns of a potential hazard the reader may be exposed to that could
result in
death or serious injury if not avoided. This admonition is not used for situations that pose a
risk only to equipment, software, data, or service. (ANSI)
CAUTION!
Warns of a potential hazard the reader may be exposed to that could
result in minor or moderate injury if not avoided. (ANSI, OSHA) This admonition is not
used for situations that pose a risk only to equipment, data, or service, even if such use
appears to be permitted in some of the applicable standards. (OSHA)
ALERT!
Alerts the reader to an action that must be avoided in order to protect
equipment, software, data, or service. (ISO)
ALERT!
Alerts the reader to an action that must be performed in order to prevent
equipment damage, software corruption, data loss, or service interruption. (ISO)
FIRE SAFETY!
Informs the reader of fire safety information, reminders, precautions,
or policies, or of the locations of fire
-fighting and fire-safety equipment. (ISO)
SAFETY!
Informs the reader of general safety information, reminders, precautions, or
policies not related to a particular source of hazard or to fire safety. (ISO, ANSI, OSHA)

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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Important Safety Instructions
Safety Admonishments Definitions
Definitions of the safety admonishments used in this document are listed under “Admonishments Used in this Document” on page iv.
Safety and Regulatory Statements
Refer to Section 4154 (provided with your customer documentation) for Safety and Regulatory Statements.
Déclarations de Sécurité et de Réglementation
Reportez-vous à la Section 4154 (fourni avec les documents de votre client) pour les déclarations de sécurité et de réglementation.

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Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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1
1Description
1.1 BAU48/4 Battery Asymmetry Unit
The mid-point voltage of battery string will deviate from the normal value (half of battery string voltage) when a short circuit, open
circuit or battery cell failure occurs in a battery string. Therefore, the BAU48/4 Battery Asymmetry Unit is available to detect this
situation. It measures the battery string voltage and the midpoint voltage respectively. It then compares the midpoint voltage with the
reference voltage that is half of the measured total battery string voltage. If the deviation exceeds the alarm threshold, the normally-
open or normally-closed dry contacts of the Battery Asymmetry Unit will activate and generate an alarm signal.
On the other hand, when the connection to the midpoint of the battery string is broken and the corresponding bit of SW2 is set to
“ON”, the normally-open or normally-closed dry contacts of the Battery Asymmetry Unit will also activate and generate an signal.
The Battery Asymmetry unit can detect the faults of up to 4 battery strings.
Included in the kit are the following:
•The BAU 48/4 Battery Asymmetry Unit
•Four Fuses (250Vac/5A) and Fuse Holders
•Two Pieces of Double-Sided Tape
•Two Mounting Screws
2Installing the BAU48/4
2.1 Planned Installation Area
Mechanical dimensions of the Battery Asymmetry Unit are shown in Figure 2.1.
2.1.1 Fastening the Battery Asymmetry Unit
The Battery Asymmetry Unit has two brackets and two double-sided tapes on its back plate. It can be installed in two ways:
Installed with Double-Sided Tape
1. Remove the paper on the tape and press the Battery Asymmetry Unit onto the installation area firmly.
Installed with Screws
1. Use the two supplied screws to fasten the Battery Asymmetry Unit onto the installation area.

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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Figure 2.1 Mechanical Dimensions
(3.86 in)
A-A
23.70 mm (0.93 in)
76.00 mm
82.23 mm
A
LEFT SIDE VIEW
TOP VIEW
(2.10 in)
(3.24 in)
98.00 mm
A

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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3Making Electrical Connections
3.1 Important Safety Instructions
DANGER! Batteries can produce large amounts of electrical current. Read and follow the “Important Safety Instructions” at
the beginning of this document before proceeding.
The Battery Asymmetry Unit has three sockets for connecting to other equipment, which are Power Supply Socket, Battery Data
Sampling Socket and Alarm Output Socket.
See Figure 3.1 and Table 3.1.
Figure 3.1 Sockets
Table 3.1 Pin Definition of Sockets
Socket Pin Wiring Description
Power Supply
+ To positive of battery
string
20V DC to 60 VDC
- To negative of battery
string
Battery Data
Sampling 1 To midpoint of battery string 1 0V DC to 60V DC
Alarm Output
Provide one pair of
normally close
contacts
Maximum power: 60W;
Maximum voltage:
220VDC/250V AC;
Maximum current: 2A;
Minimum contact
paramaters <10m Vdc
@10µA
COM
Provide one pair of
normally open
contacts
NOTE! In order to ensure the safety of the user, it is recommended that the voltage of the dry contacts shall not exceed 60V
DC or 42.5V AC.
“Contact parameters” mean the voltage and current of the relay contacts that are closed.

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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3.2 Wiring Considerations
All wiring should follow the current edition of the American National Standards Institute (ANSI) approved National Fire Protection
Association’s (NFPA) National Electrical Code (NEC), and applicable local codes. For operation in countries where the NEC is not
recognized, follow applicable codes.
Wiring the BAU48/4 Battery Asymmetry Unit is shown in Figure 3.2.
Procedure
1. The Battery Asymmetry Unit will use the midpoint voltage of the battery string as the reference voltage, so its power supply
socket can only be connected to two ends of the monitored battery string.
2. A fuse shall be connected between the midpoint of the battery string and the sampling socket of the Battery Asymmetry Unit
so as to prevent the faults of Battery Asymmetry Unit from influencing the operation of the battery string.
3. The normally open or normally closed contacts are connected to DC Power controller.
Figure 3.2 Wiring the BAU48/4

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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4Operation
Installation and operation guidance are printed on the Battery Asymmetry Unit, as shown in Figure 4.1.
•Operation Indicator: The LED (green) turns “ON” when the input power supply is normal.
•Fault Indicator: The LED (red) turns “ON” when the battery has a fault.
•SW1: Set the switch per Figure 4.1 to correspond to different alarm thresholds. The relationship is shown in Figure 4.2.
•SW2: Set the switch per Figure 4.1 to correspond to the sampling points of different battery strings. The relationship is shown
in Figure 4.2.
If one bit of the dip switch is set to “ON”, the midpoint voltage of the battery string that corresponds to this bit as shown in
Figure 4.2 will be measured by the Battery Asymmetry Unit. If the bit is set to “OFF”, the Battery Asymmetry Unit will not
measure the midpoint voltage.
NOTE! When the Battery Asymmetry Unit measures several battery strings, the user can judge which battery string has fault
by setting the bits of SW2 to “
ON ” one by one.
Figure 4.1 Installation and Operation Guidance

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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Figure 4.2 DIP Switch Setting

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5Technical Data
Environment
•Working Temperature: -10°C ~ 50°C
•Working Humidity: ≤ 95%
•Air Pressure: 86kpa ~ 106kpa
Power Supply Input and Battery Voltage Sampling
•Rated Voltage: DC 48V
•Voltage Range: DC 20V ~ 60V
•Operating Current: ≤ 25mA
Battery String Midpoint Voltage Sampling
•The midpoint voltage of up to 4 battery strings can be measured and the voltage range is 0-60Vdc.
Alarm Setting
•Alarm Threshold: ± 0.5Vdc to ± 2.0Vdc
•Adjustment Mode: 4-bit dip switch
•Step: 0.5Vdc (deviation voltage <1.5V), 0.25Vdc (deviation voltage >1.5V)
•Default Setpoint: ±1.0Vdc
Alarm Output
•Dry relay contacts are used to output alarm signals. The ratings of the contacts:
a) Maximum Power: 60W
b) Maximum Voltage: 220Vdc / 250Vac
c) Maximum Current: 2A
d) Contact Parameter: 10mVdc @ 10μA
Insulation
•DC-Enclosure ≥ 10 × 106Ω
•Test Conditions: 25 ± 5°C ambient temperature, 90% relative humidity, DC 500V test voltage
•DC-Enclosure can withstand DC 707V for one minute without breakdown and arc with leakage current less than 10mA. Test
Conditions: 25 ± 5°C ambient temperature, 90% relative humidity
Noise
•<50dB measured at 1.5m
Mechanical Data
•Dimension (H × W × D): 23.7 mm × 98 mm × 76 mm (0.93 in x 3.86in x 2.99 in)
•Weight < 0.5kg (1.102 lbs)

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
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6Troubleshooting and Repair
6.1 Contact Information
Refer to Section 4154 (provided with your customer documentation) for support contact information.

Vertiv™ BAU48/4 Battery Asymmetry Unit Installation and User Manual
Proprietary and Confidential © 2022 Vertiv Group Corp.
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