Solar panel kits are packages that include all the necessary components and accessories to install and operate a solar power system.

(1) Remote Power System Design Steps:

• 1. Identify your location & select the lowest available solar insolation in the area the equipment will be located.
• 2. Determine your load in DC Watts then duty hours per day. (To convert AC loads to DC, divide AC Watts by 0.80)
• 3. Based on your DC watt load, select the remote power system you need. You should always round up to the next largest system.
• 4. Determine days of autonomy. (Number of days of no sun for battery reserve calculation.)

(2) Sizing your System. Calculate Your Electronic Equipment's Daily Load

(EXAMPLE) Electronic Equipment Power Draw, DC Amps 1.5 Amp continuous (24 hours(1 day) load at 12 Volts DC (VDC)

• DC Voltage 12VDC
• Listed Equipment Power Draw 1.5 Amps
• Duty Cycle 24 Hours
• 1.5 X 24 = 36 amp-hours per day (Ah per day) @ 12VDC

(EXAMPLE) Electronic Equipment Power Draw Calculated in Watts

• Electronic Equipment Wattage Draw 60 Watts
• 60 Watts continuous (24 hours/day) load at 12 Volts DC (VDC)
• Duty Cycle 24 Hours
• 60 X 24 = 1440 watt-hours (wh per day)

• Watt Hours Per Day (wh/day) 1,440 wh/day
• Desired System Voltage 12VDC (48VDC)
• 1,440 wh/day /12VDC = 120 amp-hours per day (Ah/day) @ 12VDC

*STC - To learn more about solar panels and how they are measured you need to know what STC stands for. STC in an acronym for "Standard Test Conditions". All solar panels are rated in Watts. The watt rating is how much power (amps times volts) the panel will produce in full sunlight at 25 degrees C (77F). This is the industry standard (STC) for all PV panel ratings (PV means Photovoltaics which is a fancy word for solar). Solar panel manufactures have long used this test standard which is 1,000 watts per square meter solar irradiance, 1.5 Air Mass and a 25 degrees C. cell temperature.

PTC is an acronym for "PV-USA". The PV-USA test conditions was developed at the PV USA test site at the University of Davis, California for standards established by the California Energy Commission that are considered closer to real world conditions (Real World Vs STC factory test conditions). The PTC rating test is 1,000 watts per square meter solar irradiance, 1.5 Air Mass, and 20 degrees C. ambient temperature at 10 meters above ground level and wind speed of 1 meter per second. In California, solar panels manufactures must be tested and rated independently at the PV USA test facility at the University of Davis (CA) to be considered for rebates.

The ambient temperature rating (PTC) is generally considered a better real world standard than factory conditions because silicon solar cells average about 20 degrees C. above ambient temperature in the real world, cell voltage drops as temperature increases. A module's power output in real life conditions is lower than the power measured at the panel manufacturing factory where cell temperature is maintained at a controlled 77 degrees F. (25 C).

STC Vs PTC Cell voltage drops about 0.08 volts per degree C. in environments which exceed 25 degrees C. That means an STC rating of 17 volts can actually become a PTC (PV-USA) rating of 15 or 16 volts. Using Ohm's Law, volts times amps is equal to watts which equals power, so a reduced voltage, means reduced watts.

Neither PTC nor STC account for all "real-world" losses. Actual solar systems will produce lower outputs due to soiling, shading, module mismatch, wire losses, inverter and transformer losses, shortfalls in actual nameplate ratings, panel degradation over time, and high-temperature losses for arrays mounted close to or integrated within a roofline.