T

Tare Loss — Loss caused by a charge controller. One minus tare loss, expressed as a percentage, is equal to the controller efficiency.

Temperature Compensation — A circuit that adjusts the charge controller activation points depending on battery temperature. This feature is recommended if the battery temperature is expected to vary more than ±5°C from ambient temperature.

Temperature Factors — It is common for three elements in photovoltaic system sizing to have distinct temperature corrections: a factor used to decrease battery capacity at cold temperatures; a factor used to decrease PV module voltage at high temperatures; and a factor used to decrease the current carrying capability of wire at high temperatures.

Thermophotovoltaic Cell (TPV) — A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the energy source for a photovoltaic cell that is designed to maximize conversion efficiency at the wavelength of the thermal radiation.

Thick-Crystalline Materials — Semiconductor material, typically measuring from 200-400 microns thick, that is cut from ingots or ribbons.

Thin Film — A layer of semiconductor material, such as copper indium diselenide or gallium arsenide, a few microns or less in thickness, used to make photovoltaic cells.

Thin Film Photovoltaic Module — A photovoltaic module constructed with sequential layers of thin film semiconductor materials. See amorphous silicon.

Tilt Angle — The angle at which a photovoltaic array is set to face the sun relative to a horizontal position. The tilt angle can be set or adjusted to maximize seasonal or annual energy collection.

Tin Oxide — A wide band-gap semiconductor similar to indium oxide; used in heterojunction solar cells or to make a transparent conductive film, called NESA glass when deposited on glass.

Total AC Load Demand — The sum of the alternating current loads. This value is important when selecting an inverter.

Total Harmonic Distortion — The measure of closeness in shape between a waveform and it's fundamental component.

Total Internal Reflection — The trapping of light by refraction and reflection at critical angles inside a semiconductor device so that it cannot escape the device and must be eventually absorbed by the semiconductor.

Tracking Array — A photovoltaic (PV) array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use both the direct and diffuse sunlight. Two-axis tracking arrays capture the maximum possible daily energy.

Transformer — An electromagnetic device that changes the voltage of alternating current electricity.

Tray Cable (TC) - may be used for interconnecting balance-of-systems.

Trickle Charge — A charge at a low rate, balancing through self-discharge losses, to maintain a cell or battery in a fully charged condition.

Two-Axis Tracking — A photovoltaic array tracking system capable of rotating independently about two axes (e.g., vertical and horizontal).

Tunneling — Quantum mechanical concept whereby an electron is found on the opposite side of an insulating barrier without having passed through or around the barrier.