As a rule of thumb, if your 300W solar panel is rated at 24 Volts (nominal), and the distance between your solar panel and the solar charge controller is less than 25 feet (7.5m), a 12 AWG Copper wire would generally be sufficient.
[pdf] A specialized inverter receives power from your solar panels and converts the DC voltage they produce directly into grid-compatible AC power. The grid-tie inverter enables your home to not just import power from the utility, but export power to the utility as well.
[pdf] 
“Storage” refers to technologies that can capture electricity, store it as another form of energy (chemical, thermal, mechanical), and then release it for use when it is needed. Lithium-ion batteriesare one such technology. Although using energy storage is never 100% efficient—some energy is always lost in converting. .
Pumped-storage hydropoweris an energy storage technology based on water. Electrical energy is used to pump water uphill into a reservoir when energy demand is low. Later,. .
The most common type of energy storage in the power grid is pumped hydropower. But the storage technologies most frequently coupled with solar power plants are electrochemical storage (batteries) with PV plants and thermal storage (fluids) with CSP plants.. .
Many of us are familiar with electrochemical batteries, like those found in laptops and mobile phones. When electricity is fed into a battery, it causes a chemical reaction, and energy is stored. When a battery is discharged, that chemical reaction is.
[pdf] 
