Absorber The layers used to absorb sunlight.
Acreage The total acres used up by a photovoltaic system.
Activated shelf life The time it takes for a charged battery to reach an unusable level when stored at a specific temperature.
Activation voltage The voltage that the controller will operate at to protect the batteries.
Air mass In terms of solar energy, the air mass relates to the path length of solar radiation through the atmosphere. For instance, an air mass of 1.0 means that the sun is directly overhead and the radiation travels through one atmosphere of thickness.
Alternating current (AC) Electrical current that constantly reverses direction of flow.
Ambient temperature The air temperature of the surrounding area.
Ammeter A device ...