The Off-Grid Solar Panel System Calculator helps you size the battery bank, watts of solar panels and the solar charge controller you need. The calculator assumes you will need to size your system to get you through average amount of sun-light in the least sunniest month of the year for your location. This calculator assumes and adds for inefficiencies in batteries, panels, and wiring. Battery Bank Sizing This calculator will help you size the battery bank for your system. Step 1: Your Daily Energy Usage: Example: 14 amps x 240 volts for 8 hours = 27000 wh Watt Hours per Day: (Amps x 240 volts x hours) You can take monthly kwh from electric bill and divide by 30 for daily wh total Step 2: How Many Days Should Your System Run without Sun? How many days of backup power do you want in case of cloudy/rainy days? Step 3: Adjust the Effective Capacity of Your Battery Bank Due to Low Temperatures What is the lowest temperature your battery bank will experience? 80F (27C)70F (21C)60F (16C)50F (10C)40F (4C)30F (-1C)20F (-7C) Degrees (Florida and Bahamas choose 80F) Results: Select a battery bank voltage: 122448 Note: All calculations assume a 50% discharge to your batteries to optimize battery life and 10% inefficiency Solar Panel and Solar Charge Controller Sizing This calculator helps you size the solar panel(s) and charge controller(s) needed for your system. Step 1: Determine the Solar Exposure for Your Site You need to determine the average number of sun-hours per day during the least sunniest month of the year. This is the ‘Isolation Value’ Select the State-City Closest to your location (currently only US states are provided) – Select a City – Ba – Andros IslandAK – FairbanksAK – YakutatAL – MontgomeryAR – Fort SmithAR – Little RockAZ – TucsonAZ – PrescottAZ – PhoenixCA – Santa MariaCA – San FranciscoCA – BakersfieldCA – FresnoCA – Los AngelesCA – DaggettCA – Long BeachCA – ArcataCO – EagleCO – PuebloCO – Grand JunctionCO – BoulderCT – BridgeportCT – HartfordDE – WilmingtonDC – WashingtonFL – JacksonvilleFL – Key WestFL – MiamiFL – TallahasseeFL – TampaGA – AtlantaGA – SavannahHI – HonoluluIA – Des MoinesID – BoiseIA – WaterlooIL – ChicagoIN – IndianapolisKS – TopekaKS – Dodge CityKY – LexingtonLA – Lake CharlesLA – New OrleansLA – ShreveportMA – WorcesterMA – BostonMD – BaltimoreME – CaribouME – PortlandMI – Saulte Ste. MarieMI – LansingMN – St. CloudMO – ColumbiaMO – St. LouisMS – MeridianMT – GlasgowMT – Great FallsMT – Miles CityNC – CharlotteNC – Cape HatterasNC – GreensboroND – BismarckNE – OmahaNJ – NewarkNM – AlbuquerqueNV – Las VegasNV – ElyNY – BinghamtonNY – BuffaloNY – AlbanyNY – SyracuseNY – New York CityOH – ColumbusOH – ClevelandOK – TulsaOK – Oklahoma CityOR – AstoriaOR – PortlandOR – MedfordPA – PittsburghPA – EriePR – San JuanRI – ProvidenceSC – CharlestonSD – Rapid CityTN – NashvilleTN – MemphisTX – San AntonioTX – BrownsvilleTX – El PasoTX – WacoTX – Fort WorthUT – Salt Lake CityUT – Cedar CityVA – RichmondVT – BurlingtonWA – SeattleWA – OlympiaWI – Green BayWI – MadisonWV – CharlestonWY – Lander or Manually enter the average sun-hours for your location. Florida and Bahamas = 5 Step 2: Sizing Your Solar Panel Power Needed The total wattage of Solar Panels that you need is: Watts, or kilowatts This value takes into account losses due to system inefficiencies. Step 3: Determine How Many Solar Panels You Need in Your Array How many solar panels do you need? That depends on the panel you choose. Select the wattage of the panel your interested in, and see the results below: Please Select10204050606570758085100110120130135155165170175180185190195200205210215224225235239 watts per panel You will need panels for a total of watts. Sizing your Solar Charge Controller You will need a charge controller that can handle amps A Flex 80 from Outback can only use 5000 watts of panels at 80 amps, so if your total wattage exceeds 5kw you need to add additional charge controller.
