Solar facts

Smart Energy

Charging with solar energy

In order to obtain the optimal energy level from sunlight using Rubytec solar chargers, it is useful to know the various factors that influence charging. The 4 most significant factors that influence charging are the following:

  1. Position of the sun

    For best results, place the solar charger so that the sun’s rays strike the solar panels perpendicularly.
    Position of the sun

  2. Time of day

    Charging using sunlight will produce the most energy between 9 a.m. and 3 p.m. The hours prior to and after these time periods are much less efficient.
    Time of the day

  3. Degree of cloudiness

    The degree of cloudiness can influence the result of charging using solar energy. A clear sky will naturally have the best result.
    Degree of cloudiness

  4. Position on the earth

    The position on the earth determines the angle of incidence of the sun and the corresponding light production. The closer you are to the equator, the better your result.
    Position on the earth

Lux and MCD

The lux (symbool lx) is a unit of lighting strength: 1 lux is the strength produced by 1 candela on a surface perpendicular to the light rays at a distance of 1 metre from the source.

The light strength of a candle is approximately equal to 1 candela; a 100 watt light bulb has a light strength of approximately 120 candelas. The light strength of LEDs or LED lights is expressed in millicandelas (MCD). 1000 millicandelas is equal to 1 candela (CD). For example, the Rubytec Naxos has 5 LEDs. The light strength per LED is 15,000 MCD or 15 CD. The total light production of the Naxos is 5 x 15,000 MCD = 65,000 MCD (65 CD).

Charge time

The charge time that is indicated in the specifications of the various Rubytec solar chargers is based on sunlight (130,000 lux). To give you an idea of the maximum light production by various light sources, below are several examples:

  • Sunlight: 130,000 lux
  • Day light, indirect sunlight: 20,000 lux
  • Cloudy day: 1000 lux
  • Office: 400 lux
  • Very dark day: 100 lux
  • Twilight: 10 lux
  • Dark twilight: 1 lux
  • Full moon: 0.1 lux
  • Quarter moon: 0.01 lux
  • New moon with no clouds: 0.001 lux
  • Cloudy night with no moon: 0.0001 lux