Samlexpower BBM-1225 - Installation; Installation Diagram and Dimensions; Cable Sizing, Termination and Fusing

6 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 7
Battery Backup Application Using 12V, 40-100 Ah Battery
ThisBatteryBackupUnithasbeenpresetforbatterybackupapplicationfora12V
batteryofapproximately40to100Ahcapacitywiththemaximumchargingcurrent
limitedtoapproximately4A(Atpowersupplyvoltagesetat14.0Vandbattery
dischargedto11.1V).
Battery Backup Application Using 24V, 40-100 Ah Battery
Whenusingthisunitinthepresetconditionfor24V,40-100Ahbatterybackup
application,thechargingcurrentwillincreaseapprox.twotimesto8A(Atpowersupply
voltagesetat27.6Vandbatterydischargedto22.3V).
Calculating Maximum Battery Charging Current
MaximumbatterychargingcurrentIb={(Vp – Vd)–Vb} divided by Rs……….Equation 1
Vp=Outputvoltageofthepowersupply(14Vfor12Vbatteryand27.6Vfor24Vbattery)
Vd=ForwardvoltagedropacrossSchottkyDiodeD1(upto0.5V)
Vb = Battery voltage
Rs=Equivalentseriesresistance.Inthiscase,R1(1.2Ohm)andR2(1.2Ohm)in
parallel=0.6Ohm(SeeFig3.1).
Assumingthevoltagesoffullydischarged12Vand24Vbatteriestobe11.1Vand22.3V
respectively(atDischargeRateofaroundC/10(0.1C)Amps),themaximumcharging
currentswillbeasfollowsasper Equation 1:
For 12 V battery backup=(14V–0.5V–11.1V)dividedby0.6Ohm= 4A
For 24 V battery backup=(27.6V–0.5V–22.3V)dividedby0.6Ohm=8A
SECTION 4 | Installation
4.1 INSTALLATION DIAGRAM AND DIMENSIONS
Fig3.1showstheinstallationdiagram.DimensionaldetailsaregivenatFig2.3.
4.2 CABLE SIZING, TERMINATION AND FUSING
Thesizeofthecablesusedtoconnectthepowersupply,thebatteryandtheloadto
thisunitwilldependuponthemaximumvalueofthecurrentowandthelengthof
thecablerun.Currentowingthroughacablewillproduceanundesirablevoltage
dropalongthelengthofthecable.Thevoltagedropisproportionaltotheresistanceof
thecable.Higherresistanceproduceshighervoltagedrop.Theresistanceofthecable
increasesasthecablebecomesthinner.Similarly,theresistanceincreaseswiththelength
ofthecable.Itisdesirabletolimitthevoltagedropto2%whichwillbe0.24Vfor12V
batteryand0.48Vfor24Vbattery.
SECTION 3 | Description and Principle of Operation