Solar Basics


Photovoltaic (PV) cells convert sunlight into electrical energy. An individual PV cell is usually small, typically producing about 1 or 2 watts of power. To boost the power output of PV cells, they are connected together in chains to form larger units known as modules or panels. Panels can be used individually, or several can be connected to form arrays. One or more arrays is then connected to the electrical grid as part of a complete PV system.

Photovoltaic Cell Module and System Graphic


PV cells come in many sizes and shapes, from smaller than a postage stamp to several inches across. Solar cells are often less than the thickness of four human hairs. In order to withstand the outdoors for many years, cells are sandwiched between protective materials in a combination of glass and/or plastics to make a PV module. 


PV modules and arrays are just one part of a PV system. Systems also include mounting structures that point panels toward the sun, along with the inverters that take the direct-current (DC) electricity produced by panels and convert it to the alternating-current (AC) electricity used to power all of the home and devices.

Which battery type is best for solar—flooded, sealed or lithium?

 Solar batteries fall into three main categories. From least to most expensive, they are:

  • Flooded lead-acid (FLA)
  • Sealed lead-acid (SLA)
  • Lithium-Ion

Flooded lead-acid battery technology has been aeound for more than 100 years.  They require monthly maintenance by mostly refilling the battery with distilled water, which evaporates during the charge cycle.

Sealed lead-acid batteries also use a lead-acid chemistry, but are sealed to prevent off-gassing. They are also maintenance-free, which removes the need for monthly checkups. Go with a sealed battery if you don’t mind paying a bit more for convenience.

Lithium-ion batteries are the premium option. They are virtially maintenance-free, charge fastest and have a longer lifespan; lasting 2-3 times longer on average than the other options.