Lighting Explained

This is for you – our customers. We wanted to explain how lighting works and what all the numbers mean. Also, we would like to explicitly highlight the differences between the different power sources to allow you to make clear and informed decisions about your lighting.

Mobile Solar Lighting Aim

Solar Mobile lighting towers have one aim, to deliver reliable adequate powerful lighting in order to carry out the works or function. These mobile lighting towers have 3 main components:

  1. Solar panels to charge the batteries during the day for the lights to work at night. ( the generator of the system)
  2. The batteries to store the power for later use
  3. The all-important lights.

With the recent rapid expansion of solar technology many companies have entered the mobile solar lighting tower market with direct imported products. Some of these imported units only have a small token of solar and rely heavily on diesel. 

Whilst Solar Hire believe that there is a place for Hybrids (when power consumption is beyond the capability of only solar) diesel should not be used if solar alone can do the job. Some of these units are just a diesel unit in disguise.

How to Calculate the Truth from the Fiction

In electrical terms we make reference to electricity in Watts (Kilowatts is x 1000, so example 2.8KWatts = 2,800 watts). Most web sites for solar will reference watts for the solar panels and the lights, the batteries can also be referred in watts but many sites use amp hours and volts, this can be confusing to some people so we prefer to stay with one standard being Watts!

For a solar lighting tower to function reliably, it needs to have power generation greater than the light power.

Many sites will quote the size and quantity of panels but not the average power generation in winter (that’s when the nights are longer and we get less sun). But don’t worry it’s easy to get an estimate – If a site says they have 4 x 250 watt solar panels that equals 1000 watts (1KW)  of power.

This means 1Kw per hour of generation is how much power is produced in a day. It’s not straight forward as the solar panels only produce max power when the sun is directly in front of the panel. However, there is an easy rule of thumb that if you times the hourly generation i.e. 1 KW by 4 =  4000 watts (4KW) this is an approximate, but it is close.

Lighting is referred in watts i.e. , 4x 100 watt LED lights, this totals 400 watts, in the average night (winter is around 14 hours at the Sydney latitude) we need to run the lights for at least 12 hours so 12 x 400 watts = 4,800 watts (4.8KW).

The above example will not work, if you only generate 4KW and use 4.8KW your tower batteries will be flat in a few days (depending on how many batteries you have). (Unless your Solar Tower has a diesel generator)

Mobile Solar Lighting Power

Mobile Solar lighting plants have only become possible due to the recent efficiencies in solar panel technology and the development of highly efficient and very powerful LED technology.

In a rule of thumb (there are many variables age of the lights is a major factor) recent LED technology has given an efficiency of 160 Lumens per watt, in short 400 watts of LED is equal to around 1000 watts of the diesel plants Metal Halide lights.

Solar Hire has reviewed numerous articles produced in Australia and the USA, relating to the use of mobile lighting plants in general. The theme of these articles has been, to create light sufficient to carry out the task or function without interference to the surrounding communities.
Our belief is why burn excessive diesel creating half a million lumens when, one hundred thousand lumens by solar is more than enough to light the work zone to a safe level. Over kill just costs money, adds CO2 for no reason. (Mining is an exception, the size of the equipment and the area to be lit are extensive and require the appropriate lights)

We must not only consider the power of the lights but how we use it and where it should be focused.
Light shrouds are a good simple way to capture light that was heading to the stars and off to the sides and direct it to where it’s needed.
Solar Hire has stocks of lights from wide floods to narrow spots and highly recommends that a lighting plan is considered in order to get the maximum Lumens onto the job area.

Choosing the Right Lights

There are an enormous number of different lights from Pressure Sodium to Metal Halides and LED being the most commercially viable.

High Pressure Sodium Lights

High pressure sodium lights work by creating an electric arc through vaporized sodium metal, while additional materials and gases work to start the lamp and control the its colour.

Benefits of High-Pressure Sodium (HPS)

  • The main benefit of using HPS is that they are the only light source with a similar efficiency to LEDs and maintain luminescence fairy well.

Disadvantages of High-Pressure Sodium

  • Firstly, HPS lights have a very narrow colour spectrum, limited to warm deep yellow light.

  • They also have the worst CRI of any light source and require a warm-up period.

  • Towards the end of their life they flicker on and off.

Metal Halides

Metal Halide lamps produce light by passing an electrical current through a mixture of mercury and Metal Halide gas.

Benefits of Metal Halides

  • Metal Halides also have a very high source of white CRI light, making them ideal for applications that need the most correct representation of colour.
  • Metal Halides are much more efficient and higher quality than incandescent bulbs.
  • While Metal Halides are great for high output applications such as, sports stadiums and construction.

Disadvantages of Metal Halides

  • They have the longest warm-up time period of any light, sometimes up to 20 minutes to reach full operating temperature.
  • Metal Halides must be operated for longer periods of time since on/off is not instant.
  • Their average lifespan being 6,000 to 15,000 hours at most for each bulb.
  • Metal Halide has a low efficiency of 45% as they lose lumen output over time.
  • They are omnidirectional meaning they produce 360 degrees of light.


LED stands for ‘Light Emitting Diode’, a semiconductor device that converts electricity into light. An electrical current passes through a microchip, which illuminates the tiny light sources we call LEDs and the result is visible light.

Benefits of LEDs

  • Extremely long lifespans +50,000 hours
  • Very high energy efficiency
  • Extremely high light quality and little to no maintenance costs.
  • LEDs have a general CRI range from 65-95.
  • LEDs have instant on/off, meaning they require no warm-up or cool down time.
  • LEDs emit light with a 180-degree spread, which is ideal for directional lighting.

Disadvantages of LEDs

  • After a solid review of the disadvantages of LED lighting, there were a few highly technical engineering points but none that inhibited their use in the Mobile Lighting plant operation.


Photometrics is the technology employed to evaluate the amount of light required to illuminate a particular area to specific Lux levels.
While these levels are only recommendations for particular work types and industries they are based on a good foundation of experience from the USA to Australia.

Solar Hire intends to utilise this technology to assist customers in the selection of product and how it is best set.

Given the lighting requirements of the work site Solar Hire has a number of options to include onto our solar towers to best suit our customer needs.
Examples include:
1) Light shrouds to prevent light pollution and to better focus light in the correct area.

2) Street light extension poles, these are aluminium poles set on to our tower head tilt. By remote control you can swing the pole over the road way acting like a street light while having the main lights focused on your work site.

3) Using flood or spot lights, this is where a lighting plan will enable Solar Hire to set up your solar tower with specific lights for your unique job environment. Service with a smile.

4) Shadowing is quite a nuisance to night workers but is unavoidable, but with a lighting plan this inconvenience may by significantly reduced.

5) Lighting plans may be a good record-able document in the case of accidents. This being a document, that shows due consideration to the overall site safety management plan was in place.

Example of photometrics below.