[33] Calculation Type Units
Estimated Watt demand
[1] Total Watts Per Hour (DC) Watts
Hours per day
[2] Equipment running time Hrs d -1
Watt-Hours per day
[3] Total daily usage   Watt-Hrs d -1
Amp-hour calculation
[4] Total watts   Watt-Hrs d-1
[5] Corrected for battery losses   Watt-Hrs d-1
[6] System voltage Volts
[7] Amp-hours per day   Amp-Hrs d-1
Battery bank calculation
[8] Days backup power required days
[9] Amp-hour storage Amp-Hrs
[10] Depth of discharge 0.5 fraction
[11] Required amp backup Amp-Hrs
[12] Battery Amp/hr Rating (20 hr) Amp-Hrs
[13] Actual # batteries wired in parallel  
[14] Batteries wired in series  
[15] Rounded number of Batteries  
Solar Panel Array calculation
[16] Sun hours per day (Direct only) Hrs
[17] Worst-weather multiplier 1.55 fraction
[18] Total sun hours per day Amp-Hrs
[19] Select panel size (Watt rating) Watts
[20] Nominal Panel Voltage 16 Volts
[21] Amps required from solar panels 15 Amps
[22] Peak amperage of solar panel Amps
[23] Number of solar panels in parallel  
[24] Number of panels in series (12 V)  
[25] Rounded number of solar panels  
Inverter Sizing
[26] Power Factor (0.8) PF
[27] Inverter VA rating VA
[28] Inverter backup time hours
Estimated power (Amps) required to charge the Battery bank
[29] Recharge Factor (10 - 15%) PF
[30] Estimated recharge time hours
[31] Constant load   Amp-Hrs d-1
[32] Estimated recharge power Amps

Reference:

  1. ^ Total Watts Per Hour (DC Amps x 12):
    The real power drawn by the equipment is expressed in Watts or Volt-Amps (VA). Add the total Watts of your appliancies and write the total in the space provided in the table. This field needs to be DC watt draw only. If you are using an inverter, meaning your device is rated in AC amps and 110 V, you will need to convert that number into DC watts before entering it in the field. Then you will need to add about 10% due to the inefficiency of the inverter. To get there, use the following formulas; 1 Amp AC = 10 Amps DC. (example, 2AC amps =20DC amp) Add 10% (22 amps) DC amps x 12v = DC watts. (22 x12 =264 watts) 264 would be entered in field -
  2. ^ Hours Equipment is expected to run as per application:
    for how many hours you expect your equipment to run in a 24 hour period, and your input voltage (12, 24, 36?).
  3. ^ Total daily usage is Watts x Hours:
  4. ^ Total watts required per day:
  5. ^ Assumes static average loss:
  6. ^ System DC voltage only:
  7. ^ Amp-hours per days is Watts divided by Volts:
  8. ^ Days backup power required (Average 24 hour periods):
    determine what size and how many batteries you need. -
  9. ^ Amp-hour storage. Raw capacity you need:
  10. ^ Depth of discharge. Assumes 50%:
  11. ^ Required amp backup. Prevents excessive discharge:
  12. ^ Battery Amp/Hr Rating:
    determine what size and how many batteries you need. -
  13. ^ Actual # batteries wired in parallel. Raw number:
  14. ^ Batteries wired in series relates to system voltage:
  15. ^ Rounded up number of Batteries:
  16. ^ Sun hours per day (Direct only):
  17. ^ Worst-weather multiplier * (1.55 default):
  18. ^ Total average sun hours per day:
  19. ^ Solar panel size (Watt hour rating):
  20. ^ Nominal Panel Solar output Voltage:
  21. ^ Daily Amps consumption required from solar panels:
  22. ^ Peak amperage of solar panel. Watts divided by Volts:
  23. ^ Number of solar panels in parallel:
  24. ^ Number of panels in series (12 V) (it is 1 for 12v, 2 for 24v, etc):
  25. ^ Rounded number of solar panels :
  26. ^ The Power Factor for a standard home is 0.8 max.
  27. ^ You should prefer an inverter of 20% or more for the best choice.
  28. ^ How long will it take before the inverter dies on you.
  29. ^ recharge factor is the additional energy required to charge a battery , usually it is
    about 1.1 to 1.15 . It means it needs 10 to 15 % more energy to make up for what
    has been removed from the battery.
  30. ^ Desired charge time in hours = 8 to 12 hours
  31. ^ Energy consumed by Constant load.
  32. ^ Estimated power required to charge the battery.
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