How to Power Appliances With Solar Panels

How to Power Appliances With Solar Panels

It’s an oversimplification to visualize a appliance drawing power directly from a solar panel, but the reality is not that much different. A complication arises because the panel output signal is generally direct current — not alternating current — and it usually is not at a voltage which the appliance can use. A device called an inverter resolves this complication. Apart from an inverter, many working systems include batteries, so you can continue to use appliances once the sun is not out.

Photo-Voltaic Principles

Impinging sunlight creates a potential difference between the 2 sides of a solar cell, and when you connect those sides with a conducting cable, a current will flow. A typical panel consists of a range of these cells wired together to generate a fixed potential difference, or voltage, of 12, 24 or 48 volts. Based on the square footage of the panel, the current that flows when you connect the terminals might be sufficient to charge a computer, but to run any kind of motor or power an appliance, you usually need to wire a few panels together.

Charging a Battery Bank

Most photo-voltaic systems are installed to charge a battery bank that’s installed at precisely the exact same voltage as the panels. Panel output fluctuates with variations in sunlight, and these fluctuations can harm the batteries. You prevent this by wiring a charge controller between the panels and the battery bank. Besides stabilizing the panel output to a steady signal the batteries can manage, the charge controller monitors the batteries and shuts off the input when they are charged. It also prevents electricity flowing back to the panels in the batteries, which may harm the panels.

The Inverter

After you’ve got a panel array connected to a battery bank by means of a charge controller, and the bank is charged, you still aren’t ready to power almost any appliances. That’s because the output from the batteries is DC, and it’s at 6, 12, 24 or 48 volts instead of the 120 volts needed by the appliance. Now you want an inverter to convert the DC battery power to a modified-sine or pure sine wave AC signal, and to alter the voltage. Inverters are rated for the amount of electricity they supply. A 300-watt tonsils, that can be on the small side, will conduct a small appliance.

Plugging In

Inverters have regular 120-volt grounded receptacles that accept any appliance plugin, but you must be sure the appliance does not draw more than the inverter can handle. In that case, you want a bigger inverter. Some panels include an integrated charge controller and inverter, and you also can plug directly into the receptacle supplied on the panel. These systems typically don’t provide much electricity, however, and are generally only suitable for charging mobile phone or computer batteries. Any power-hungry appliance like a blender or vacuum cleaner will necessitate the output of a sizable battery bank and the charging power of more than one panel.

See related