How to Measure the Amperage of a Solar Panel

Amperage, or amps, is a unit measure of the amount of electrons conducted through a wire in one second. It differs from voltage, or volts, which expresses the potential resistance to electrons as they travel along a wire. Amperage is the electrical current, whereas voltage is the force needed to push the currents along the wire.

The amperage of solar panels determines the size of the system needed to meet the electrical requirements of your house. In this case, it is only an estimation. The value for amperage is obtained by dividing watts by voltage.

Things You'll Need

• Volt meter
• Watt meter

Instructions

Solar Panel Electrical Output

1. Calculate the watts used in your home using a watt meter. Watts are the amount of electrical power used to perform work at one rate when one amp flows through a potential resistance of one volt.
   You can plug in every appliance, piece of electronics and lamp into the watt meter and record the usages or you can estimate using your utility meter or bill for your entire house.

2. Calculate the voltage of your home. Homes in the United States use 120 volts, but you may want to measure and record the voltage of each appliance you plan to hook up to your solar panel system. You can wire appliances directly to your solar panels for power. Amperage is required to ensure the right number of panels are hooked up to meet your appliance energy requirements.

3. Divide watts by voltage. Use the meter readings you obtained per appliance or per your home and run your calculations. For example, a 60-watt light bulb connected to a 12-volt battery will draw 5 amps: 60/12 =5.

4. Figure out your solar panel size requirements by using panel ratings. A general rule of thumb is that a solar panel rating of 15 watts delivers 1 amp per hour in direct sunlight. Calculate the amount of direct sunlight each panel will receive and multiply the number of sunlight hours times the number of 15-watt panels which equals amps/hour. Most solar electricity is stored in a battery.

   Using the above calculations, you can estimate that you would need five solar panels to power a 60 watt light bulb from a 12-volt battery.

References

• Electrician-ElectricalContractor.com: Calculate Amperage
• BatteryStuff.com: Solar Tutorial
• Iowa State University: Amperage