Battery Management System for Telecom Applications ... - Ericom

Why a BMS is Needed?
Battery Management System for Telecom Applications
GSM operators prefer 12V VRLA batteries by 4
serial in group to use in 48V DC backup
systems . 4 x 12V batteries forms a ‘’group’’ and
3-4 groups are parallel connected to reach
required Ah capacity
Parallel connections between battery groups
can cause ‘asymmetric’’ charge current
distribution
Telco rectifier systems are designed to charge
one battery group with one current control. It
does not care current distribution between
parallel battery groups. It only controls current
and voltage limitation for total Ah capacity.
In real life VRLA batteries cannot be produced
identically. Production differences can effect
battery aging rate and serial / parallel connected
batteries show asymmetrical characteristics for
a while.
Beatrice Telco-BMS Structure
Small capacity differences between 12V
batteries cause asymmetric internal resistance
behavior during charge and discharge.
Difference increase with cycling and aging. This
situation creates asymmetrical distribution of
charge current and cause exceeding of charge
current limit of battery group (mostly 0,15C).
Charge current out of limits cause faster aging
of battery.
Asymmetrical capacity aging of batteries cause
‘’inter group charging’’ during discharge stage.
Higher voltage (higher SoC) group feeds the
load and ‘’charge’’ other groups. This overloads
the battery group.
All of these problems affects aging parameters
of VRLA batteries and shorten their operation
life
Ericom Beatrice has been designed to solve
all of these problems
Ericom Telecommunication & Energy Technologies Inc.
Adr: Buyukdere Cd. No: 15/A Hur Han B Blok Kat:3 34381 - Sisli / Istanbul / Turkey
Tel: 0212-330-05-40 Fax: 0212-330-05-43 Web: www.ericom.com.tr

BBC x (Battery Bank Controller)
Features:
• ‘’Buck’’ topology for DC-DC conversion
• 8 Bit PIC microcontroller
• Hall Effect current sensor
• 1-20 A charge current limitation (CC - Constant
Current) 42-54V battery group charge voltage
(default 53.5V) CV (Constant Voltage)
• Temperature compensation parameter for each
battery group
• MODBUS derivated text protocol between BBCx
and MPC
• Overcharge and overdischarge protection by
using voltage and temperature measurement of
each 12V VRLA battery.
• Battery group isolation in case of fatal failure of a
battery
MPC (Main Process Controller)
Features :
• 8 Bit PIC microcontroller
• Data logging into onboard SD Flash card (8GB)
• Maintenance PC interface via DB9 - RS232
• Proprietary VRLA battery charge algorithms and
SoC / SoH determination methods
• 4 x 4 LED matrix for battery state display to
maintenance technician
• GSM/GPRS modem connection via secondary
RS232 port on board
• Remote monitoring and management server
support
Environmental:
Working Temperatures : 0 .. 50 0 C
Relative Humidity: %90 RH
Electrical:
Input Voltage : -42…-56V DC
Output Voltage : -42…-55V DC
Output Current : 0 … 20 A
Physical Dimensions:
9 x 44 x 42 cm (Hx W x D)
19 inch rack compatible, 2U
Weight: 3.5 Kg
Ericom Telecommunication & Energy Technologies Inc.
Adr: Buyukdere Cd. No: 15/A Hur Han B Blok Kat:3 34381 - Sisli / Istanbul / Turkey
Tel: 0212-330-05-40 Fax: 0212-330-05-43 Web: www.ericom.com.tr