Operation Of Battery Back-Up - Samlexpower SEC-40BRM-220 Installation & Operating Manual

OPERATION OF BATTERY BACK-UP

WARNING! THE BATTERY SHOULD BE LOCATED IN A WELL VEN-
TILATED AREA TO SAFELY DISSIPATE HYDROGEN GAS
PRODUCED DURING THE CHARGING PROCESS.
D1, D2 SCHOTTKY DIODE: 30V, 180A
R1, R2 POWER RESISTOR: 0.78 OHM, 35W
R STATIC LOAD RESISTOR: 120 OHM, 5W
Please refer to the schematic at fig. A above.
Regulated output voltage of 14.2VDC +/ - 1% from the modules ( measured at screw
terminals S5 and S6 (Fig.1) is fed to the positive and negative DC bus bars and from
there to the output terminals LOAD+ and LOAD- through the isolating Schottky Di-
ode D1. Although the output voltage at the module terminals S5 and S6 ( Fig.1) or at
the common DC bus bar (before the Schottky Diode D1) is tightly regulated at the
preset value of 14.2VDC +/ - 1%, the voltage at the output terminals Load + and
Load - will vary slightly due to the forward voltage drop of the isolating Schottky Di-
ode D1 and the drop along the DC bus bar and wiring. The voltage at the output
terminals LOAD + and LOAD – will be as follows :
At no external load
At 10 A load
At loads > 10A
When there is a requirement of un-interrupted D.C. power to the load, an external
battery may be connected at the terminals Battery + and Battery –. When the input
A.C. power is available, the load current is supplied by the power supply through
isolating Schottky Diode D1. At the same time, the battery is charged through resis-
tors R1 & R2. (These resistors will limit the maximum charging current to about 8
Amperes.)
FUGURE A.
Approx. 14V
Approx. 13.8V
Approx. 13.8V minus 5mV per Amp above 10A
7.