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4. Calculate Size of Inverter / Battery Bank

CALCULATE SIZE OF INVERTER & BATTERY BANK

Calculate Size of Inverter for following Electrical Load .Calculate Size of Battery Bank and decide Connection of Battery.

Electrical Load detail:

  • 2 No of 60W,230V, 0.8 P.F Fan. * 1 No of 200W,230V, 0.8 P.F Computer. * 2 No of 30W,230V, 0.8 P.F Tube Light.

Inverter / Battery Detail:

  • Additional Further Load Expansion (Af)=20% * Efficiency of Inverter (Ie) = 80% * Required Battery Backup (Bb) = 2 Hours. * Battery Bank Voltage = 24V DC * Loose Connection/Wire Loss Factor (LF) = 20% * Battery Efficiency (n) = 90% * Battery Aging Factor (Ag) =20% * Depth of Discharge (DOD) =50% * Battery Operating Temp =46ºC

Temp. °C Factor 80 1.00 70 1.04 60 1.11 50 1.19 40 1.30 30 1.40 20 1.59

CALCULATION:

Step 1: Calculate Total Load:

  • Fan Load= No x Watt =2×60=120 Watt * Fan Load=(No x Watt)/P.F=(2×60)/0.8= 150VA * Computer Load= No x Watt =1×200=200 Watt * Computer Load=(No x Watt)/P.F =(1×200)/0.8= 250VA * Tube Light Load= No x Watt =2×30=60 Watt * Tube Light Load=(No x Watt)/P.F =(2×30)/0.8= 75VA * Total Electrical Load=120+200+60 =380 Watt * Total Electrical Load=150+250+75= 475VA

Step 2: Size of Inverter:

  • Size of Inverter=Total Load+(1+Af) / Ie VA * Size of Inverter= 475+(1+20%) / 80% * Size of Inverter= 712 VA

Step 3: Size of Battery:

  • Total Load of Battery Bank= (Total Load x Backup Capacity) / Battery Bank Volt * Total Load of Battery Bank=(380 x 2) / 24 Amp Hr * Total Load of Battery Bank= 32.66 Amp Hr * Temperature Correction Factor for 46ºC (Tp)=1 * Size of Battery Bank=[ (Load) x (1+LF) x (1+Ag) x Tp] / [n x DOD] Amp/Hr * Size of Battery Bank= (32.66 x (1+20%) x (1+20%) x 1) / (90% x 50%) * Size of Battery Bank= 101.3 Amp/Hr

Step 4: Connection of Battery:

If We Select 120 Amp Hr , 12V DC Battery for Battery Bank:

Series Connection:

  • Series configurations will add the voltage of the two batteries but keep the amperage rating (Amp Hours) same. * Condition-I : * Selection of Battery for Voltage = Volt of Each Battery <= Volt of Battery Bank * Selection of Battery for Voltage =12< 24 * Condition-I is O.K * No of Battery for Voltage = Volt of Battery Bank / Volt of Each Battery * No of Battery for Voltage =24/12 = 2 No’s * Condition-II : * Selection of Battery for Amp Hr = Amp Hr of Battery Bank <= Amp Hr of Each Battery * Selection of Battery for Amp Hr =3<=120 * Condition-II is O.K * We can use Series Connection for Battery & No of Battery required 2 No’s

series_battery_config Configuration

  • In Parallel connection, the current rating will increase but the voltage will be the same. * More the number of batteries more will be the amp/hour. Two batteries will produce twice the amp/hour of a single battery. * Condition-I : * Selection of Battery for Amp Hr = Amp Hr of Battery Bank / Amp Hr of Each Battery <=1 * Selection of Battery for Amp Hr =101/120 = 0.84=1 No’s * Condition-I is O.K * Condition-II : * Selection of Battery for Voltage = Volt of Battery Bank = Volt of Each Battery * Condition-II :Selection of Battery for Voltage for Amp Hr = 24<=12 * Condition-II is Not Full Fill * We cannot use Parallel Connection for Battery as per our requirement But If We do Practically It is Possible and it will give more Hours of back

parallel_battery_config Connection:

  • Connecting the batteries up in series will increase both the voltage and the run time. * Condition-I : * Selection of Battery for Amp Hr = Amp Hr of Each Battery <= Amp Hr of Battery Bank * Selection of Battery for Amp Hr =120<=101 * Condition-I is Not Full Fill * Condition-II : * Selection of Battery for Voltage = Volt of Each Battery <= Volt of Battery Bank * Selection of Battery for Voltage = 12<=24 * Condition-II is OK * We cannot use Parallel Connection for Battery

If We Select 60 Amp Hr , 12V DC Battery for Battery Bank:

Series Connection:

  • Selection of Battery for Voltage = Volt of Each Battery <= Volt of Battery Bank * Selection of Battery for Voltage =12< 24 * Condition-I is O.K * No of Battery for Voltage = Volt of Battery Bank / Volt of Each Battery * No of Battery for Voltage =24/12 = 2 No’s * Condition-II : * Selection of Battery for Amp Hr = Amp Hr of Battery Bank <= Amp Hr of Each Battery * Selection of Battery for Amp Hr =3<=60 * Condition-II is Not Full Fill * We can use Series Connection for Battery

Parallel Configuration

  • Condition-I : * Selection of Battery for Amp Hr = Amp Hr of Battery Bank / Amp Hr of Each Battery <=1 * Selection of Battery for Amp Hr =101/60 = 1.63=1 No’s * Condition-I is O.K * Condition-II : * Selection of Battery for Voltage = Volt of Battery Bank = Volt of Each Battery * Condition-II :Selection of Battery for Voltage for Amp Hr …