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Purchase, NY 10577
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Some systems require most of these functions, others require only one or a certain combination. Our design can select a unit to meet your specific needs.
Charge controllers are rated and sized by the array current and system voltage. Most common are 12, 24, and 48-volt controllers. Amperage ratings run from 1 amp to 60 amps, voltages from 6-60 volts.
For example, if one module in your 12-volt system produces 7.45 amps and two modules are utilized, your system will produce 14.9 amps of current at 12 volts. Because of light reflection and the edge of cloud effect, sporadically increased current levels are not uncommon. For this reason we increase the controller amperage by a minimum of 25 percent bringing our minimum controller amperage to 18.6. Looking through the products we find a 20-amp controller, as close a match as possible. There is no problem going with a 30-amp or larger controller, other than the additional cost. If you think the system may increase in size, additional amperage capacity at this time should be considered.
Voltage of the battery bank - 12, 24 or 48 V DC
The PV industry really began with the 12V recreational vehicle market. These systems were typically small (1-2 solar modules) and had all 12 VDC loads. As the solar industry matured and entered the home market, systems became much larger (16+ solar modules) and no longer used DC loads exclusively. Same holds true about wind turbines. as size increased, the output voltage also increased. Most home systems today are 24 or 48 V DC since the higher system voltage gives you a lot more flexibility as to how far away you can place your solar modules from the battery bank as compared to a 12V system. For a given power output, a higher system voltage reduces your amperage flow (but not your power) which allows you to use a smaller and less expensive gauge wire for your solar to battery and battery to inverter wire runs. Of course, if you already have a lot of 12 VDC loads, that may be your deciding factor as to what voltage you set your system up at. Most grid-tied systems operate at 48 volts or higher.
Let us provide you with an assessment of your need.
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