- LOW
VOLTAGE BATTERY DISCONNECT (LVBD)
THE
LOW VOLTAGE BATTERY DISCONNECT (LVBD)
OPTION ADDS A NEW DIMENSION TO BATTERY
BACK-UP OF THE TECHNOLOGY DYNAMICS LINE
OF HIGH RELIABILITY POWER SUPPLIES. THE
DC OUTPUT OF THE POWER SUPPLY SIMULTANEOUSLY
CHARGES THE BATTERY AND POWERS THE LOAD.
WHEN AN AC INPUT POWER FAILURE OCCURS,
THE BATTERY CONTINUES TO POWER THE LOAD
WITHOUT ANY POWER INTERRUPTION TO THE
LOAD.
THE
LVBD MODULE OPTION ELECTRONICALLY MONITORS
THE BATTERY VOLTAGE. WHEN THE BATTERY
VOLTAGE GOES BELOW A PREDETERMINED (ADJUSTABLE)
LEVEL, THE LVBD MODULE AUTOMATICALLY DISCONNECTS
THE BATTERY, THEREBY PROTECTING THE BATTERY
FROM A COMPLETE DISCHARGE. THIS LEVEL
IS USUALLY SET TO CORRESPOND TO ABOUT
1.67 TO 1.7 VOLTS PER CELL OF THE BATTERY.
THERE
ARE THREE VERY SIGNIFICANT BENEFITS TO
THE USE OF THE LVBD MODULE TO PROVIDE
BATTERY BACK-UP. THESE ARE:
- NO POWER INTERRUPTION
WHEN BATTERY OPERATION IS REQUIRED.
- 100% EFFICIENCY
WHEN BATTERY OPERATION IS USED.
- BATTERIES
ARE PROTECTED FROM PERMANENT DAMAGE BY
EXCESSIVE DISCHARGE
SINCE THE BATTERY IS CONNECTED ON THE
OUTPUT OF THE REGULATED POWER SUPPLY,
IT IS NOT POSSIBLE TO OVERCHARGE THE BATTERY.
THE USUAL RECHARGE VOLTAGE FOR A SEALED
LEAD ACID BATTERY WHEN OPERATED IN A “FLOAT”
APPLICATION IS 2.3 VOLTS PER CELL. FOR
A TYPICAL 24 VDC APPLICATION, THERE WOULD
BE 12 CELLS, THUS 12 TIMES 2.3 VOLTS PER
CELL, OR 27.6 VC. THIS CORRESPONDS TO
THE POPULAR 28 CELLS OUTPUT.
AFTER
A UTILITY POWER FAILURE OCCURS, IT IS
NECESSARY TO RECHARGE THE BATTERIES. SINCE
THE BATTERIES ARE CONNECTED ON THE OUTPUT
BUS, THE RECHARGE OCCURS AUTOMATICALLY.
THE BATTERY WILL ONLY BEGIN TO ACCEPT
CHARGE WHEN THE DC VOLTAGE GOES ABOVE
THE NORMAL OPEN CIRCUIT VOLTAGE OF THE
BATTERY. AS THE BATTERY VOLTAGE GOES HIGHER
(TOWARDS THE 2.3VOLT/CELL LEVEL), THE
BATTERY CURRENT WANTS TO INCREASE.
IN
THE EVENT OF A SHORTED CELL OR A SEVERELY
DISCHARGED BATTERY, THE POWER SUPPLY WILL
GO INTO A “CURRENT LIMIT” MODE
AND THEREFORE STARVE THE BATTERY, BUT
NOT THE CRITICAL LOAD. |
