How do Solar Fairy Lights Work? Here is our Guide :

So how do Solar Fairy Lights Work? Here is the comprehensive answer : the fairy lights or led's are nearly always attached to a control box that contains batteries. These store the power and use it when darkness falls.

How do solar fairy lights work? solar fairy lights : panel back How do solar fairy lights work? Back of the Solar power panel with control back

The control box is then in turn connected to a solar panel, which charges the batteries during daylight. The light sensor (dusk sensor) in the solar panel turns the lights on/off automatically at dusk/dawn or when the battery depletes. There are many different designs, for different countries and climates. It is important that you choose a set of fairy lights which is designed for your climate.

The Solar Panel

A solar panel turns light into electricity! It can turn nearly any light in to electricity if the source of light is strong enough, the best source is the sun because it is free and very strong.

How do solar fairy lights work? solar fairy lights : panel front How do solar fairy lights work? solar fairy lights : panel front

A good quality solar panel can generate electricity in shade or in cloudy weather, its not as much as if in full sunlight, but it is enough to use for practical applications, such as lighting with the use of energy efficient led's.

One solar panel is made up of many small solar cells, photovoltaic  cells. Each of these cells uses light to make electrons move.

The cell is made up of two different layers that are stuck together. The first layer is loaded with electrons by coating it with Boron, so the electrons are primed to jump from this layer to the second layer. That second layer has had some electrons removed by coating it with Phosphorous, so it is ready to take in more electrons.

When the light hits an electron in the first layer, the photon in the light literally knocks off one of the electrons, this causes electrons it to jump to the second layer. Those electrons make other electrons move, and so on.

This generates a voltage or electricity, this is guided around the panel, with the use of metal conductive plates. and funnelled in to a positive and negative flow. Then you just need a battery to store that energy and you are ready to go!

The control box

The control box varies with each different set of lights that you purchase, in essence the box should be acting as a regulator, guiding the electricity efficiently to the battery, and not allowing the battery to overcharge (which can damage batteries). The control box should also prevent the battery from discharging, this is called overcharge / discharge protection, and it does not come as standard in some of the cheaper control units.

How do solar fairy lights work? solar fairy lights : Control Panel How do solar fairy lights work? solar fairy lights : Control Panel

The control box can then have another level of intelligence built on to the next 'layer', some units offer multi functions to its owners, an array of different modes which provide different ways of delivering the voltage to the led's, flashing, chasing, pulsing etc. Nearly all units offer automatic lighting by way of a sensor which is built in to the panel. This sensor measures the amount of light, and when it senses that it is dark / light, it switches the lights on / off.

What are the advantages of solar fairy lights?


lighting picture of lights Bulb in hand

There are numerous advantages in using solar fairy lights, technology has made some important evolution in the last 5 - 10 years, with an increase in efficiency of solar cells and improved manufacturing techniques, solar power lights are now a true alternative to mains power, the industry in the UK has more than doubled in the past 12 months.

  • Quick and simple to install (no need for mains sockets or wiring or safety plugs)
  • Self sufficient : you can put them anywhere there is light, they also come with a 'lead' wire (wire between the solar panel and the very first led) this gives more flexibility when locating the panel. They can also for example be installed indoors on a sunny window ledge (this is for high quality units only)
  • Safer than mains powered fairy lights, the voltages involved in the average set of fairy lights is 1.2 volts compared to 230 volts for mains and yet they are just a bright!!
  • No operating costs unlike mains powered lights - saving you a great deal of money every single day you use them.
  • Turn on and off automatically using a light sensor
  • They are environmentally friendly, these units may cost the same to manufacture as the mains but after this they are money saving, and also are extremely good for the environment as they do not use any more mains power, thus reducing the greenhouse effect, and giving our children the chance of having an inhabitable planet in the near future!


Can I use them inside?


indoor solar fairy lights

Yes it is possible to run solar power fairy lights inside, however there are some caveats, the most important one is that you must purchase a good set of solar fairy lights, you can tell this by looking at the panel of the unit, if there are a lot of solar cells on it, then it is a good indication that the unit has been thought through, the battery is also important, as this is where you store the reserve of energy, a large battery can be used as a 'bridge' for those days which are very gloomy, so the unit will have spare capacity in the battery for days such as these.

The second important factor is location, with all the will in the world it is very difficult to make solar fairy lights operate facing north, and so a good bright sunny south facing window is essential. PowerBee are the only company in the UK who have produced a north facing set of fairy lights, this set has an extra ordinarily sensitive panel and electronics and will work facing north in the UK.

Is iPS Technology Relevant?

Intelligent Power Saving Technology is reported by some to be a revolutionary concept in solar technology. The electronics inside the control box measures the amount of light received by the panel over a 24 hour period. Should this measurement  fall below a certain pre-set threshold the lights will operate at night with reduced voltage, thereby in theory prolonging the run time of the lights.

There have been many counter arguments for this technology, the main premise is that if the unit is designed well, has enough solar cells, battery capacity, and efficient electronics, then this technology becomes redundant, and you are paying more for a technology which in effect dims your lights..

Do I need to change the Batteries?

Yes, rechargeable batteries do not last forever they have a certain life span, it is important to check whether you are able to change the batteries as some unscrupulous companies sell solar fairy lights where the battery cannot be replaced, which in our opinion defeats the entire purpose of being environmentally friendly. It may mean that the unit is cheaper but when the battery is exhausted this will mean you need to throw out the whole unit including the string, control box, and precious solar cells, then you will need to replace the whole set.

The batteries used vary depending on the unit and its application, in most cases the battery will be a common NiHM (Nickel-Metal Hydride) 1.2 volt, these can be purchased almost any where now a days, including supermarkets and garages.