DIY Manual

13 | P a g e 10-543-1 REV A
DIY Manual
PHOTOVOLTAIC (PV) MODULES
A basic solar system consists of solar panels, a charge controller, and batteries. This chapter of
the DIY Manual focuses on the solar panels, or photovoltaic modules, or simply PV.
UNDERSTANDING PV MODULES
A solar panel is made of individual silicon cells, wired in series to produce a specific output
voltage. Typical panels are made in 60- or 72-cell configurations. 3 types of panels:
1. Polycrystalline: cells are made of composite silicon. Usually less expensive per watt
than monocrystalline panels, and slightly less efficient than mono. Poly panels are
discernable by the medium to dark blue tint of the cells.
2. Monocrystalline: Manufactured from a single silicon block, mono panels have a near
black appearance, are usually a bit more expensive than poly panels, and are more
productive in low light conditions, such as early morning/early evening hours and
during cloudy conditions.
3. Thin film: Least productive type of panel, therefore more costly per watt compared
to mono or poly panels. Where extreme ambient temps are a concern, thin film
works best in very hot and cold environment. Thin film is flexible and impact
resistant, making it a good choice for boats, solar backpacks, and to minimize
damage from vandalism.
Panels are manufacturer-tested under Standard Test
Conditions (STC): exposure to artificial light at the
intensity of 1000W per square meter at 77
o
F (25
o
C).
Results of the test are recorded on a sticker found on
the backside of the PV module.
• Voc – Open Circuit Voltage. Maximum
voltage output, used to determine max
series-string input voltage to the charge
controller. Read Wiring and Circuit Breaker
Protection chapter of this Manual for more
Photovoltaic – “Voltage produced by (sun) light.”