A VRLA battery (valve-regulated lead–acid battery), more commonly known as a sealed battery or maintenance free battery, is a type of lead–acid rechargeable battery. Ventilated or Sealed? Gel or Glass Mat? Sealed are best for sites with low ventilation but work well everywhere. Other features should be compared so you can make the best choice for your system.
Charge controllers monitor battery charging and redirect the panel output to a diversion load, such as a hot water heater, when the batteries do not need charging. There are two types of charge controllers, PWM and MPPT.
The main function of a PWM charge controller is to control the voltage coming in batteries. A MPPT charge controller can send control signals to panel aiming systems.
Inverters regulate the electricity generated by your solar panels. Some inverters are for smaller systems and mount directly on each panel. Other inverters are for large systems where many panels are fed to one inverter. There are inverters for On or Off Grid. There are also inverters that do both on and off grid.
Solar PV modules generate electricity using sunlight. A typical panel generate 250 to 350 watts. Four panels will generate 1000 to 1400 watts of power. Usually 8 to 12 panels comprise a residental system. This number of panels easily fits on most roofs of medium and larger size homes.