| Starting from the monthly electric bill... |
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| 1. Record the Electric Bill Monthly Consumption. |
660kwh |
__________ |
Monthly Consumption |
| 2. Divide Monthly Bill by Number of Days in Month = Daily Consumption |
660 / 30 = 22 kwh |
__________ |
Daily Consumption |
| 3. Divide Daily Consumption by number of Sun Hours at your location.* |
22 kwh / 5.5 hours = 4000 Watts |
__________ |
Hourly Consumption by Sun-Hours |
| 4. Hourly Consumption by Sun-Hours / Efficiency Correction Factor. ** |
4000 Watts / 0.69 = 5797 Watts |
__________ |
Hourly Consumption by Sun-Hours (Corrected) |
| 5. Hourly Consumption by Sun-Hours (Corrected) Divided by Size of
Solar Panel Chosen. |
5797 Watts / 175 Watt Panel = 33.12 Panels [32 or 34 Panels]*** |
__________ |
Each 175 Watt Panels |
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| * 5.5 Sun Hours might be your Annual Average. Winter Months will
be shorter and summer months will be longer. For Grid-Tie it might be ok
to use Annual Average, but for Off-Grid (not Metered Electricity) one
should use the Winter Sun Hours to prevent a shortage of power in the
winter. |
| ** 0.69 Correction factor includes Inverter Efficiency
0.94 x Battery Efficiency 0.90 x Panel Efficiency 0.82. |
| *** 32 Panels can be reduced by lowering the electrical
consumption of the House. For every dollar in a lower
electric consumption, you will save $5-10 in the cost of Solar Panels and other
equipment. |
