| Many people think you just throw up some solar | | | | conductor such as a wire. It can also go through |
| panels and bask in the electricity. Well, that is true, but it | | | | insulators, semi-conductors or even in electron or ion |
| helps to test them to make sure things are working | | | | beams. In direct current, the electric charges flow in the |
| efficiently. | | | | same direction, distinguishing it from alternating current. |
| Electrical current is measured in amperes. To test a | | | | Direct current is primarily used for low voltage |
| solar panel, attach a meter, called an "amp meter" that | | | | applications. A photovoltaic solar electric panel |
| can measure amperes, to the positive and negative | | | | generates DC power when it is exposed to sunlight. |
| terminals on the panel, and expose the panel to full | | | | The power usage of the appliances that one might |
| sunlight. Make sure that the amp meter is rated higher | | | | power with a solar panel or array, or by the batteries |
| than the solar panels are, so that you don't damage | | | | they charge, is measured in watts. Wattage is |
| the meter or cause yourself injury. The measurement | | | | calculated as P=E*I, where P=Power, E=Voltage and |
| on the meter is called the "short circuit current", and it is | | | | I=Current. By measuring the voltage and amperage of |
| the amount of current you can expect from the | | | | a solar panel and plugging into this equation, one can |
| panels. | | | | determine the power production of the system and if it |
| An alternate method of determining the power output | | | | will be sufficient for the required needs. |
| of a solar panel is by measuring the voltage of | | | | A solar charge controller is usually used in constructing |
| resistors which all have different values. In order to | | | | a solar power system. It works to regulate the power |
| conduct the test, you would need multiple resistors as | | | | coming from the PV panel into the rechargeable |
| well as a digital multi-meter which is used to measure | | | | battery. There are several components which might |
| the DC voltage. Once the measurements are made, | | | | be included. A potentiometer can be used to adjust the |
| the power output can be calculated using the equation: | | | | float voltage. Most contain an equalize function which |
| Current = Voltage / Resistance. A performance graph | | | | helps which occasional overcharging and a |
| can then be created for the panel by plotting the | | | | temperature compensation function which works to |
| power output. | | | | automatically provide the best battery charge |
| Current can either be AC (alternating current) or DC | | | | depending on temperature. It is recommended that you |
| (direct current). Direct current, also known as DC or | | | | attempt to match the battery's amp-hour rating with |
| continuous current, is the constant flow of an electric | | | | the maximum current on your solar panel. |
| charge. In most instances, the current flows through a | | | | |