Sizing Correctly
the
Off Grid Solar Power System

Find the right size of the Off Grid Solar Power System

You need to know the following information before you can estimate the size of the off grid solar power system.

• Your average monthly consumption. You can prepare a list of your appliances, lighting bulbs, home electronics and all other electricity consumers. For each one, you need to write down how frequent and for what duration it works (refrigerator is on all the time but it works in cycles, washing machine is operated a few times in a week etc.). For each consumer calculate its monthly electricity consumption by multiplying its consumption in KWh by the time in hours it operates during a month. Sum the consumption up to get your average monthly consumption
• Think off-grid. Remove from the list appliances that can operate not on electricity, a good example is a solar hot water heater. Use washing machines, drying machines, dish washers and ovens during daylight as much as possible and with full load. Use CFL bulbs or LED lighting. (the purpose is to scale down the solar panels size and the batteries size as much as possible)
• What is the daylight consumption and what is the after sunset consumption

After that you can calculate the size of the components

• calculate your average daily consumption (divide the monthly average by 30)
• divide the daily consumption by the average number of useful daylight (6-8 hours, dependent on location and season) to get the size of the solar panels in watts
• The size of the inverter and the charge controller should fit the size of the solar panels
• Think of the batteries as a pool of water that is filled during the day and drained over nights.(You store electricity in during the day to be used over night and over cloudy hours). You can’t however discharge the batteries bellow the 20% line (the charge controller is taking care that you won’t). The capacity in KWh of the batteries when fully charged is the Ah (Amper-hours) rating multiplied by the voltage (there are 12V, 24V and 48V batteries) multiplied by 0.8 (remember the 20% bottom line). This should suffice for your night time consumption. So you calculate backwards from your night consumption (divide it by the voltage rating and by 0.8) to get the batteries size in Ah (take some spare for rainy days).(if you have a wind generator and wind is expected after sunset you may reduce the size of the batteries array)
• I won’t be surprised if you find out that you need many batteries, and that you need a battery rack

Shopping Hints

Although it might looks complicated, most on-line stores and off-line stores for solar products if they worth their name will provide you with assistance, calculators and other support. A good contractor, worth his reputation can give you a technical proposal and a price quotation for a turn key job. Don't ignore the energy tax credit available for clean off grid power investments. The IRS approves 30% with no limit, most states add state level incentives. long term subsidized financing is available in some of the states

Now that you have the big picture you can click here for a variety of off grid solar power offered by this big store,Solar Power products