Residential energy: A comprehensive guide to solar-powered lights and lighting at home

Introduction

It might seem rather odd, using solar power to run lights. After all, if the sun's bright enough to power a light, it would seem unlikely that you'd need the additional light source. And if it's dark enough to need a light, where's the solar energy coming from?

This article looks at how solar powered lights work, what they do, and the different options available and how to choose what’s most suitable for you.

Solar lights are essentially like mini satellites. Satellites generate and store energy when they are facing the sun, and use it when they are in darkness. That’s exactly how solar lights work.

Solar powered lights are most often used in the garden, as they can absorb light during the day and release it at night.

Most solar powered lights designed for gardens, ponds, driveways and car parks are self contained units; each individual light has its own solar cells and panels and charging system in order that it can work independently.

It is also possible to have a number of lights strung together by wires connected to one solar energy collection point and series of solar panels, but this does negate some of the advantages of having solar powered lights outside.

The outdoor lights used in this way tend not to be as bright as, say, electrically powered floodlights, but for the purposes for which they’re generally designed mean they don’t need to be.

Solar-powered lanterns on a terrace, outdoors. Copyright Ian Muttoo @ Flickr
Solar-powered lanterns on a terrace, outdoors. Copyright Ian Muttoo @ Flickr
Blue LED solar-powered light set in tall grass
Blue LED solar-powered light set in tall grass

The advantages of solar lighting

There are significant advantages to installing solar powered lights outside your home or business.

Generally speaking, as they are self contained units, there is no wiring.

There is certainly no need to try to run mains electricity outside from the house or business in order to power lights, and no need to worry about extensive insulation to protect electric wires from the weather.

Because of this wireless-ness, they are particularly suitable for use in or near water features.

Another advantage to there being little in the way of wiring means that they’re much easier to install than standard floodlights or outdoor lights, and cheaper.

And of course, lower electricity bills, and the environmental benefits of not using carbon-powered electricity to light up the outside.

Solar powered Christmas lights, are for example, a great use of solar technology. They come in all different types with a number of lights, style, colour and so forth.

They cost a bit more than those that need to be wired in, but are free to run and therefore cheaper in the long run as well as more environmentally friendly.


Solar Tier Light 6-Pack
Solar Tier Light 6-Pack

6 budget solar lights, each a self-contained unit. They install by being driven into the ground. Pluses - LEDs, price, warranty. Minuses - plastic case.

 
Malibu 3 Pack Solar Landscape Plastic Flood Light Set with Remote Panel, Textured Black #LZ413
Malibu 3 Pack Solar Landscape Plastic Flood Light Set with Remote Panel, Textured Black #LZ413

Pack of 3 varied-installation lights; can be driven into the ground or attached to trees, etc. Separate solar panel, and the 3 lights are connected by 40 ft of wire. Pluses - LEDs, Ni-MH batteries, two-year warranty, bright enough to read by, solar batteries can be replaced. Minuses - not for general illumination (spotlights, really), 3 units must be fairly close together, plastic case

 
Malibu Outdoor Metal Bollard Four-Light Solar Powered Light Kit #LZ635RP4/LZ635RPL4
Malibu Outdoor Metal Bollard Four-Light Solar Powered Light Kit #LZ635RP4/LZ635RPL4

Bollard-style post lights for driveways or pathways. Separate solar panel, and units wired together to function from it. Pluses - metal case, good price, reliable and good blue-white LED lights. Minuses - must be placed fairly close together, supplied batteries not the best (can be replaced cheaply, with better ones)

 
Gecko sunning itself on a solar light, copyright Rhea C
Gecko sunning itself on a solar light, copyright Rhea C
Solar powered streetlight, Denmark
Solar powered streetlight, Denmark

Where best to use solar lights

Solar powered lights are particularly useful in gardens, to light up trees, paths, water features, or particular features of the garden, or patios and terraces.

They are also useful installed on a footpath or driveway, or just outside a house so that it’s not dark when a person is coming home and trying to get in.

This has security benefits as well as making it easier to see where you’re going.

As well as the more standard year round type of lights, its also possible to buy solar powered Christmas lights for outdoor trees, and, “novelty” features such as solar powered globes floating in ponds, lit up solar energy gnomes, and small lights to illuminate keyholes or house signs and numbers.

There are different types and features in relation to solar lights, for example, lights which are on constantly when its dark, or those which are motion sensitive.

How solar-powered lights work

A normal solar light consists of a case and the decorative part of the light together with any stands or attachments.

It has a solar cell, or series of cells wired together as a solar panel, and a rechargeable battery.

It has an electronic board to control the device, a light bulb, and a photoresistor which can tell whether it’s light or dark.

The cases are of course the most variable part. Like normal mains-powered lights, the cases come in small and large, are made of different materials, with stands or screws to attach them to trees or similar.

An average solar-powered light for the garden or driveway contains between 4 and 8 solar cells wired in series so that they work together. This solar panel is then connected to a rechargeable battery via a diode. This prevents the battery’s current from going back to the solar cell at night, and wasting it.

During the day, when sunlight is falling onto the solar panel, the solar cells absorb the energy and charge the battery. The light is not on at this time, at it isn’t needed, which means that all the solar energy absorbed goes to charging the battery and not powering the light.

The photoresistor is light sensitive, and detects whether or not it is light outside. When the photoresistor detects little or no solar energy reaching it, it activates the light and turns it on.

Most solar lights also have an override, so that you can turn them off on very dark days in order to allow the battery to recharge fully, or stop it coming on during the day if its very dark.

MAXSA Innovations 40225 Solar-Powered Motion-Activated 80 LED Security Floodlight
MAXSA Innovations 40225 Solar-Powered Motion-Activated 80 LED Security Floodlight

80 LED security floodlight, with 180 degree motion detector operating up to 35 feet. Separate solar panel, so light can be positioned out of direct sunlight. Good number of LED bulbs for this price, but does come with lead acid battery (see text to the left)

 
Solar Powered 15 LED Security Light and Motion Detector 2013
Solar Powered 15 LED Security Light and Motion Detector 2013

LED security motion-sensitive solar light. 15 LED bulbs, and NI-MH modern battery, too. Separate solar panel, so can be positioned without the light being in direct sunshine.

 
Designers Edge L-949 10-LED Rechargeable Solar-Panel Shed Light
Designers Edge L-949 10-LED Rechargeable Solar-Panel Shed Light

Light suitable for use inside shed, garage, or outhouse. Has 10 LED bulbs, and separate solar panel. Very useful indeed for non-mains buildings, and has Ni-cam battery, too.

 

Choosing solar lights - bulb type

Generally speaking solar lights use one of two types of bulb.

Older systems and some of the cheaper ones available today use standard incandescent bulbs. They work with lead acid batteries. These are less efficient, as the bulbs burn out much more quickly and need changing, and are less efficient at translating stored solar energy into light at nighttime.

The lead acid batteries are also less efficient at charging, and take fewer charges before they are exhausted.

Newer, and slightly more expensive, solar lights use a Light Emitting Diode bulb and nickel cadmium or nickel metal hydride batteries.

LEDs produce brighter light, more efficiently, and also last a lot longer than incandescent bulbs.

The nickel cadmium batteries are more efficient at converting solar energy and holding a charge, and can be recharged many more times than a lead acid battery.

LEDs are an extremely energy efficient form of light bulb. LED bulbs reduce energy consumption by between 80 and 90% compared with traditional incandescent bulbs.

They last for approximately 100,000 hours (an average, of course, but the average is an awful lot better than traditional bulbs).

LEDs are also made using less in the way of nasty pollutants. Fluorescents, for example, also last a very long time but they’re more difficult to dispose of. They contain mercury which can be extremely poisonous and needs to be disposed of properly.

I’d suggest it’s not really worth buying solar lights with incandescent bulbs or lead acid batteries; they are less environmentally friendly and far less efficient.

Choosing solar lights - lights on when dark, or motion-activated

Most solar powered lights sold come with the photoresistor panel which means that they are on once dusk falls.

These are useful if you want permanent lighting on your terrace or patio or to light up garden features or a driveway.

It is also possible to get solar lights with motion sensors. These are useful as security lights, if you don’t want light shining in when you’re trying to sleep, or to conserve the battery if you’re not getting much direct sunlight during the day.

In addition, some units have both. They have a dimmer, permanently-on photoresistor activated light, with a brighter light switching on as the result of a motion sensor.

Choosing solar lights - integrated solar panel or separate?

Some solar-powered lights have an integrated solar panel, that is, the solar panel is on top of the light itself. This is more common, but means that when you install the light you need to make sure that it will be in direct sunshine.

If you want to attach solar-powered lights in places shaded by trees or sheds, or to the house in order to light a terrace or patio, you can buy solar-powered lights where the panel is connected with a wire which means that you don’t have to install the solar powered light in direct sunshine.

When choosing solar lights to buy, it’s important to think about where you might want to install them.

If you’re going to put them on say a driveway or near a pond, then it’s likely you would want an integrated unit.

Integrated units only work where the unit is in direct sunshine, so if you want to light up trees, or your driveway or the garden is shaded, you might want to look at having the solar panel detached from the main light unit.

Until you know where you want to install it, it’s going to be difficult to know which type of light to go for.

Choosing solar lights - wood, plastic, or metal cases?

Once the technical details are sorted out, all you need to decide is what you want your lights to look like. Not surprisingly, as with any lights, there is a vast choice of casings and decorative designs.

Many are plastic, which does seem to me rather to defeat the point of trying to install environmentally-friendly lighting. Plastic is, of course, largely made from oil, a fossil fuel.

Nevertheless, if price is a consideration, the plastic solar lights do tend to be cheaper and appeal on that basis.

It’s also possible to get solar lights with metal cases, and there are innovative designs made of wood, and even shells.

This is really a décor and taste question rather than a technical one.

The most common easy-install method for a solar-powered light involves driving the spike at the bottom on the light into soil.
The most common easy-install method for a solar-powered light involves driving the spike at the bottom on the light into soil.

Installing solar powered lights

Installing solar lights tends to be pretty easy.

You don’t need to worry about electricity installing or an electrician, which makes it much cheaper and easier to install solar lights than traditional outdoor lights which need to be connected to mains electricity and proper insulated.

Most of them are an entirely self-contained and sealed unit, and therefore all you need to do is open the box, assemble any bits of the case that need assembling, and nail it to the tree, attach it to the roof or drive it into the ground as appropriate.

If you choose lights with a separate solar panel, you will need to mount and install that separately.

Either way, unless you are extraordinarily inept, you won’t need to pay someone to install it for you.

Maintaining solar powered lights and extending their life spans

Maintaining solar lights is pretty easy. As they’re self contained units, they need very little fiddling with.

If you live in a place far north or south of the Equator with very short daylight hours in the winter, you might want to turn the photoresistor off for a few days in the winter to allow the battery to recharge fully. This will extend the life of the battery.

Apart from that, all you need to do is clean the solar panel with a duster occasionally to keep off any dirt or dust that prevent the solar panel from working at maximum efficiency.

Other than that, you can just leave it alone and enjoy the green light.


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Comments 24 comments

Narayan 7 years ago

Thank you very much. This is very useful specially for our country where load shedding is 16 hours a day. However I have one question. Can you please write if there is also a system/equipment that gets energy from sun and good enough to run fridge, TV and computer as well.


BrianS profile image

BrianS 7 years ago from Castelnaudary, France

As usual a comprehensive and useful report on renewable energy products. One or two of these items look like they might be just what I need to solve a lighting problem or two for me.


countrywomen profile image

countrywomen 7 years ago from Washington, USA

Very useful hub for alternative energy sources. I wish more people in India relied on Solar energy where sunlight is in abundance. Good informative hub.


Tatjana-Mihaela profile image

Tatjana-Mihaela 7 years ago from Zadar, CROATIA

I used solar lights in the garden of my weekend house. They are practical, so nice and cheap.

Thumbs up for good Hub!


BristolBoy profile image

BristolBoy 7 years ago from Bristol

This is a really useful hub. I feel that solar lighting has a great advantage in situations where it is impractical to connect up to the grid. In most western countries this means in people's gardens, yet in many countries such as those in Africa it can be the first source of electrical lighting that many people have. In addition, this replaces other sources of lighting, such as charcoal, wood and kerosene which give off bad fumes particularly in enclosed spaces, and so the greater use of solar lighting is literally a matter of life and death. And in many of these siutations, due to the cost of fuels and the increased light levels, it is actually cheaper to use solar lights. However, the main downside to solar lights in such situations is access to the product for remote communities, and the relatively high initial capital cost. Once this has been overcome though, such as through schemes organised by Selco Solar, there will not only be less environmental damage in many poorer areas of the world, there will also be great improvements in the quality of life of the inhabitants (due to less fumes and more disposable income).


LondonGirl profile image

LondonGirl 7 years ago from London Author

Hi Narayan - you need to look at generating electricity from solar energy to do all that - have a look at this article: http://hubpages.com/technology/Residential-solar-p...


LondonGirl profile image

LondonGirl 7 years ago from London Author

Brian, glad you found it useful! Lots of sun in your neck of the woods (-:

Countrywoman, India's ideal for solar energy, and I think the use of it is growing there quite fast.


LondonGirl profile image

LondonGirl 7 years ago from London Author

Tatjana, glad you are enjoying your solar lights!

BB, I agree with everything you've written, the only shame is that you put it so much better that I did!


SweetiePie profile image

SweetiePie 7 years ago from Southern California, USA

I never heard of solar powered Christmas lights, but that sounds very interesting. Usually do not get a tree myself, but I might pass this information on to my sister.


LondonGirl profile image

LondonGirl 7 years ago from London Author

I'm going to talk my parents into getting some - we don't have a Christmas tree, but they do and we spend the festival there.


blondepoet profile image

blondepoet 7 years ago from australia

London girl you are a great beauty everyone is looking at you http://hubpages.com/entertainment/Hubbers-Celebrit...


LondonGirl profile image

LondonGirl 7 years ago from London Author

That is a fantastic hub, thanks for pointing it out to me!


2patricias profile image

2patricias 7 years ago from Sussex by the Sea

Pat says - I have solar powered lights in my garden, mainly to pick out the edges of the flower beds. I bought a batch of cheap plastic ones, and then later some more expensive metal ones. I live close to the sea, and the metal ones have gone rusty! This is something to bear in mind for anyone thinking of buying these. Thanks for another well researched hub.


GeneriqueMedia profile image

GeneriqueMedia 7 years ago from Earth

Very wonderful and useful stuff. A bit..dreary, but then again, you're doing your best to spruce up such a common topic.

Solar powered flashlights.. ;)


LondonGirl profile image

LondonGirl 7 years ago from London Author

Thanks Pat - if the metal is iron, and not sealed, rust would be a risk, you are right.

Gen - glad you found it useful, sorry it was dreary (-:


DIYSolarEnergy profile image

DIYSolarEnergy 7 years ago from USA

Was searching for information on how to select solar lights and saw your hubpage on choosing and selecting the best ones. Great info on the advantages of using solar lights and how to distinguish between them!


Aya Katz profile image

Aya Katz 7 years ago from The Ozarks

LondonGirl, thanks for this article on solar lights. I know that you said they are best for the garden and walkways, but why is that? Is it because indoors there is not sufficient access to the sun?

I would love to install solar lights in Bow's pen, for those days that are not bright enough. During storms, the sky darkens and the pens become very dark. But I don't want the lights to come on at night, because that's when Bow sleeps. (In fact, I hate outdoor lighting at night. It interferes with natural rhythms of rest and waking, and it also makes it hard to see the stars.)

Are there portable lights that can be placed outdoors all day and brought in on a dark day?(And which won't just automatically come one at night?)


Build Your Own Solar panel 7 years ago

Very interesting. I like the solar lights you have pictured, but I have not been impressed with how much light they actually put out after dark. Do you think there will be a brighter bulb available?


suziecat7 profile image

suziecat7 7 years ago from Asheville, NC

Really great and informative Hub. I'm a fan.


LondonGirl profile image

LondonGirl 7 years ago from London Author

Aya, the reason they are usually recommened for outdoors is, as you say, so that they can charge. But there are some which can be installed with a separate solar panel on the roof, or you can take it outside when it's sunny, and bring it back in again when you want it. The automatic setting can always be over-ridden, don't worry.


LondonGirl profile image

LondonGirl 7 years ago from London Author

Build, there is already quite a variety of bulbs. Some lights have more than one (I've seen up to 15 or so) in one light source. Having said that, I have no doubt they will continue to improve rapidly.


spartanking1978 profile image

spartanking1978 6 years ago from Earth

Renewable forms of energy are here to stay. It is the responsibility of every American to demand strict renewable energy standards. Send an email to your state legislators...the time for change is now!


adair_francesca 6 years ago

A very useful hub. I believe that people should consider the use of solar power more. It is really a great alternative and investment. Thanks for your wonderful hub, it gives great information about green energy and available solar powered devices that we can use.


BristolBoy profile image

BristolBoy 3 years ago from Bristol

Solar powered garden lights are very good - I believe they are one of the best things possible!

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