Samlexpower SAM-1000-12 Owner's Manual - Section 4 |
12 | SAMLEX AMERICA INC.
Anexampleofthiscalculationfora12Vinverterisgivenbelow:
Let us say that the total continuous ac Watts delivered by the 12V inverter = 1500W.
Then,usingFormula2above,theDCcurrenttobedeliveredbythe12Vbatteries=
1500W÷10=150Amperes.
next, the energy required by the load in ampere Hours (ah) is determined:
Forexample,iftheloadistooperatefor3Hours,thenasperFormula3above,theenergy
tobedeliveredbythe12Vbatteries=150Amperes×3Hours=450AmpereHours(Ah).
finally, as per rule of thumb at formula 4, the ah capacity of the batteries should be
twice the energy required by the load in ah=450Ahx2=900Ah.
Dc input power terminals
Custom made DC input terminals using M9 Nut / bolt arrangement have been provided
for connecting DC input cables (10, 11 in fig 3.1 to 3.3). The terminals are protected by
plastic covers.
important Wiring/cabling information
Although wires and cables are good conductors of electric current, they do have some
resistance, which is directly proportional to the length and inversely proportional to the
thickness(diameter)i.e.resistanceincreasesinthinnerandlongerwires.Currentflowing
through resistance produces heat. Cables and wires are covered with insulating material
thatcanwithstandaspecifiedtemperatureoftheconductorunderspecifiedconditions.
Toensurethattheinsulationisnotdamagedduetoexcessiveoverheating,eachwiresize
hasamaximumallowablecurrentcarryingcapacitycalled"Ampacity"whichisspecified
byNECTable31.15(B)(17).Further,NECalsospecifiesthatwiresizeshouldbebasedon
Ampacity-1.25timestheratedcurrentflow.
resistance of wires and cables produces another undesirable effect of voltage drop. Volt-
agedropisdirectlyproportionaltotheresistanceandthevalueofcurrentflow.Voltage
dropproduceslossofpowerintheformofheat.Inaddition,excessivevoltagedropfrom
the battery to the inverter may prematurely shut down the inverter due to activation of
the Low Input Voltage Protection Circuitry of the inverter (10.5 ± 0.3V). DC cables should
besizedtoensuremaximumvoltagedropislimitedtolessthan5%.
effects of low voltage on common electrical loads are given below:
Lighting circuits – incandescent and Quartz/Halogen: Loss in light output because the
bulbnotonlyreceiveslesspower,butthecoolerfilamentdropsfromwhite-hottowards
red-hot, emitting much less visible light.
Lighting circuits – fluorescent: Voltage drop causes an early proportional drop in
light output.
ac induction motors: These are commonly found in power tools, appliances, etc. They
exhibitveryhighsurgedemandswhenstarting.Significantvoltagedropinthesecircuits
may cause failure to start and possible motor damage.