Solar 101

Assessing the Site's Potential Power

The first factor to consider when designing solar power systems is how much solar power potential does the site have --- how much does the sun shine and for how long?

At Solarcraft we base our calculations on NREL data for Typical Winter Peak Sun Hours. Using this number rather than Average Annual Peak Sun Hourrating ensures that the system delivers reliable continuous power in worst-case conditions, year after year. Other factors that affect the power rating for the site are:

  • Geographic location relative to the equator (longitude)
  • Seasonal & historical weather patterns
  • Terrain (shaded ravines, mountains, forests)
  • Particulates (sand, pollen, tree sap, ice and snow)
  • Infrastructure (shade from buildings, towers, other solar arrays)


Weather extremes impact the performance of a solar power system. Not only is sunshine affected during these events, adverse weather can damage solar arrays, over-heat or freeze batteries, or even flood systems.

  • Hurricanes
  • High winds
  • Extreme temperatures
  • Ice & snow formation
  • High water
  • Blowing sand / dust
  • Intense sunlight

Assessing Power Consumption – Daily Load Cycles

Accurate load information is essential for efficient design and reliable operation. To accurately calculate the actual 24-hour load of the system, include every component (and its 24-hour duty cycle) in the load calculation. It is critical to include the latency (power used while no load, or a small load, is present) as well.


When a system is not sized properly, the first point of failure will be the battery. An inexpensive battery becomes twice as expensive the first time you have to replace it. If the system is incorrectly designed, the batteries will continue to fail.

At Solarcraft we use only high quality American-made batteries specifically designed for the deep cycling associated with solar applications. They have a proven track record for reliability and long life.

Typical Applications

Examples of low power requirement devices suited for small solar and UPS systems are listed below:

Cautionary Advice

Technicians unfamiliar with solar power design resort to a multiplier of the total system load as a shortcut to calculate power requirements. This method works initially, but may not compensate enough for winter sunlight, sufficient capacity to handle peak power cycles, or other factors such as temperature compensation.

Companies who elect to build their own low-cost solar power systems might save money in the short term. But if they are not built correctly, these systems can result in higher replacement and maintenance costs, and operational headaches for field technicians who maintain the equipment.

  • Inefficient operations resulting from down time
  • Repair or replacement delays and expenses
  • Lost revenue
  • Liability exposure

Furthermore, when companies deploy dozens of unreliable systems, a single weather event could trigger numerous simultaneous failures, interrupting field operations.

CONTACT US TODAY to learn more about solar power system sizing, or to schedule an informative presentation Lunch and Learn.

PWM vs MPPT Solar Charge Controllers
Let Us Supply Your Key Components and Help Reduce ...

By accepting you will be accessing a service provided by a third-party external to