Page last updated

System Loads Worksheet

Use this worksheet to determine the total amp-hours per day used by all the AC and DC loads in your system.

Step A - Calculate your AC loads.  If there are no AC loads, skip to Step B.

  1. List all AC loads, wattage and hours of use per week in the spaces below.  Multiply watts by hours/week to get watt-hours per week (Wh/wk).   Add up all the watt-hours per week to determine DC watt-hours per week.

    Description of AC Loads Run by an Inverter Watts x hrs/wk = Wh/wk
               
               
               
               
               
               
    Total Wh/wk  

Note: Wattage of appliances can usually be determined from tags on the back of the appliance or from the owner's manual.  If an appliance is rated in amps, multiply amps by operating voltage (120 or 240) to estimate watts.

  1. DC watt hours per week.  Multiply line 1 by 1.15 to correct for inverter losses.
                                                                                                            ________
  2. Inverter DC input voltage; usually 12 or 24 volts.  This is DC system voltage.
                                                                                                            ________
  3. Divide line 2 by line 3.  This is total amp-hours per week used by AC loads.
                                                                                                            ________

Step B - Calculate your DC loads

  1. List all DC loads in the spaces below:
    Description of DC Load Watts x hrs/wk = Wh/wk
               
               
               
               
               
               
    Total Wh/wk  
  1. DC system voltage.  Usually 12 or 24 volts.
                                                                                                            ________
  2. Total amp-hours per week used by DC loads.  Divide line 5 by line 6.
                                                                                                            ________
  3. Total amp-hours per week used by AC loads from line 4.
                                                                                                            ________
  4. Add lines 7 and 8.  This is total amp hours per week used by all loads.
                                                                                                            ________
  5. Divide line 9 by 7 days.  This is total average amp hours per day.
                                                                                                            ________