What Is a Dusk To Dawn Light?

Dusk to dawn lights sense the level of daylight through the use of a photocell that only allows power through to the light source when measured dark enough. In other words they turn on at dusk when the sun goes down and off at dawn when the sun comes up (1).

Consider the Types of Solar Dusk to Dawn Lights 

The description of ‘dusk to dawn’ describes this light sensing functionality that can be applied to any light fitting. It is not a description of any particular type of solar light but is used generally to stop the lighting coming on in the day with their automated on and off functionality and therefore reserving battery power.

These are some of the main types of dusk to dawn solar light:

Security Light with external PV Cell

Security lighting needs to provide a high level of brightness over a wide area, so lots of power and lumen output is needed. The solar systems with external PV Cells allow you to find an optimum position to harvest the suns energy independent of the position of the light fixture. 

Security Light with Integral PV Cell

This security light incorporates the solar panel into the design of the fixture but still with some flexibility to adjust the panel to direct towards the sun. A cluster of LED chips are positioned to maximise output and efficiency.

Barn & Yard Lights 

A barn and yard light is designed to be mounted at high level on the side of a building for a broad 360 degree output usually through a polycarbonate diffuser. The PV Cell is incorporated on top facing the sky.

Flood Light or Street Light

The description of flood lights is synonymous to security lighting; both provide large amounts of light. The Flooding Light or Street Lighting tends to be a product designed for mounting on a wall or pole that directs light into a space more effectively than most other types.

Our roundup of the best solar lighting selects the first choice within all categories and more.

Choosing the Best Solar Powered Dusk to Dawn Light

You tend to buy best when you know more so take a shortcut and follow this lighting design professionals checklist. Some seem obvious but mustn’t be overlooked.

Purpose

What is the primary reason for wanting light? Do you need it for low level walkway illumination so a smaller low output light will be sufficient or mounting high needing large amounts of light?  The more output required tends to become a more commercial design which may not suit every home environment.

Power Source

The sun… through a Photovoltaic Cell that must have access to a good source of daylight and preferably direct sunlight. No wires, no switching so be aware less control compared to traditional electrical power sources. 

Brightness 

Brightness of LED light is measured by the lumen output ie 1000lm. Do not equate the higher the wattage with more light created.

Light Color and Temperature

There are a variety of types of white light available from LED sources. The warmer the light the lower the degree of kelvin, i.e. 3000K is a warm white whereas 6500K is a very cold daylight color which can feel brighter but is not a comfortable white light to be in if relaxing.

Lighting Modes

The ability to personally adapt the functionality of a light fitting allows you to select it in the knowledge that it is likely to have a mode that suits your requirements. Brightness, color, how long the light stays on for and dimming down to a standby level of light when movement isn’t detected are just some of the options. There is more to dawn to dusk lighting than simply turning off and on.

Battery Size & Quality

The energy harvested from the sun is stored in rechargeable lithium ion batteries, the higher the capacity the more energy the battery will supply to the light source. That capacity is measured in units of electric charge called mAh (milli ampere per hour). A larger capacity does not always mean larger in physical size (2).

Solar Panel Capacity

There are three factors that influence the capacity of a solar panel, the size, the material it’s made from and amount of access it has to solar irradiation. The bigger the PV Cell and the more direct it can be positioned to direction of sunlight, the more energy is harvested in the limited number of daylight hours each day. The efficacy of that conversion into energy is now better down today with monocrystalline or polycrystalline solar cells (3).

Charging Time

Each solar light should give an approximate time required for a full battery charge and some even differentiate between a sunny fast charge day against a cloudy slow charge day. A solar panel will still charge out of direct sunlight but the process is considerably slower and likely to not be a full charge by night fall and in turn shorten the run time in the evening.

Illumination Time 

The length of illumination is dependent on the energy stored and the wattage of LED being used, so a manufacturer should estimate a run time on a full charge to give you an idea. Many dawn to dusk lights will not come on and stay on all the time but to aid longevity only stay on for 30-45 seconds if movement is detected with a PIR sensor.

Illuminated Area

How far the light will spread out from the fixture is useful to know and without actually testing it we are all at the mercy of the manufacturer’s buying guides. We like to look at any previous customer comments too to add some real world info as there isn’t a useful metric to compare models to each other.

Size

As an LED chip is a miniature light source, they are clustered into ‘arrays’ to unify as a single source of light when all turned simultaneously. The more LED chips, the larger the light source. This enables a manufacturer to make a solar source of light from a small step light to large street lights. 

Style

Decorative sources of dusk to dawn light will encapsulate the LED source and PV Cell into a pleasing package that suits the intended style and hides the battery. It is fair to say the more light that is required from the light, the more utilitarian it ends up looking, bordering on the ugly! 

Design and Durability

Your exterior lighting is subject to all weathers with the solar panel needing to be in unabashed direct sunlight and therefore exposed to all the extremes. In general plastic is the best choice for outdoor use compared to other materials, resisting UV light, they can be fade resistant and very durable (4). Powder coated metals and non corrosive aluminium are also suitable choices.

Water Resistance Certification

All exterior electrical products, even battery supplied solar lighting, should be protected against the ingress of moisture. If not always for the protection of an electrical shock as some run as extra low voltage, it’s for the longevity of the product. Certifications of IP44 as splashproof and IP65 as water jettable are commonly seen.

Motion Detection Range

PIR motion sensors (Pyroelectric Infrared Sensors) are commonly found on dawn to dusk solar lighting to allow it to choose what to do when movement from a human or animal is detected. The lens over the sensor determines the width of detection range and specified in degrees (5). For example, a 270 degree detection range is very wide and will pick up everything near it, whereas a 90 degree angle will only detect movement mostly in front of it and not be triggered by peripheral movement. The more your light comes on the more energy is used so the right choice of sensor can stop possible wastage from unwanted passers by.

Automatic On/Off

There are not many uses for an artificial light source in the day, so the precious electrical charge is reserved for the dark, ready for action at dusk and switched off automatically when the sun comes up in the morning. This is the main form of control for most solar lights as they are not connected to a lighting circuit.

The light source can also be switched off automatically when nobody is near it (see PIR above) and can also turn off after a predetermined duration. Each model has different characteristics.

Remote Control

Infrared hand held remote controls are available in some solar lighting for a neat method of interacting with a single or group of solar lights. This added level of control can also be useful where individual control of specific lights is needed, for example you want some lights to turn on with a motion sensor but others not.

Easy Installation

The main consideration for solar lighting installation is ensuring the location is suitable for charging. Apart from that there are no cables and switches required so install is relatively easy and often at a DIY level of difficulty.

Value for Money

The advise is to buy as well as you can afford as solar lighting will give you incredible value for money. There will be a little maintenance required as the rechargeable battery will need replacing at some point but apart from that the lifespan is long with no running costs!

Warranty

Any product that carries more than a one year manufacturer’s warranty is worth considering over other less confident designs for exterior lighting. However, do not be fooled by limited warranties that look good at possibly 3 years but only cover a part of the product. Much of the dawn to dusk solar lighting market is at the budget entry level end and that can only mean a lower build quality.

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