Under the Choko Tree By Nevin Sweeney

Low Cost Solar Lighting

These days it is possible to install a back-to-the-grid solar generating system based on photovoltaic panels and an inverter for a few thousand dollars. It will help to offset our electricity bill while a favourable feed-in tariff is in place and reduce our carbon footprint. However, the system won’t be much use during a power outage.

Similarly it is possible to install a stand-alone alternative power system using photovoltaic panels, wind generators or micro hydro or a combination to generate power. The electricity generated is stored in deep cycle lead acid batteries and then conveyed to the point of use, with or without recourse to an inverter. This system will be of use in the event of a power failure but requires time, effort, expertise and (dare I say it?) money to design and install.

You may not have the cash for either system, be a renter instead of an owner or just not want to go to all that trouble. If you do want to design-your-own 12 volt power system, see here to read about my experiences. But if you don’t, what are the options?

I’m glad you asked!

There are a number of small, inexpensive, solar charged components which can be used either by themselves or in combination to help you develop your own solar lighting system. If you are not flush with cash and/or do not own the property where you are living this could be the answer for you. You can save money on your electricity bill as well as reducing your carbon footprint and still have light if the power goes out!

Solar Garden lights

These come in a huge number of designs and can be very cheap, as low as a couple of dollars each in the el cheapo shops or upwards of $50 each in the more upmarket establishments, depending on the design. Needless to say, I am talking about the low end of the market!

Solar garden light in place

These lights are generally composed of a small solar panel which sits on top of the casing and faces the sun, a single LED light, an off/on switch and a battery of some description. The set-up can also sense the sun so that the light only comes on at night. Quite often the solar panel/light/battery assembly can be removed from the casing which allows it to be charged and used as a light inside your house. If you are shopping around, go for the one with the biggest battery so that it will give you the longest life on a days’ charging in the sun.

Solar panel, battery and light unit removed

A friend of mine was having difficulties with the battery not contacting the metal contacts and so the lights were not working. In the configuration of light he had, he pulled everything apart and secured the small panel, light and battery to a baseboard and soldered the contacts to each side of the small round watch batteries which powered his lights. He lined four up together to make a light that he would leave out in the sun and then bring in at night when it was ready for use.

Inside the unit showing AAA battery

The type I found allowed the whole top assembly to be removed from the lens and the rest of the casing so they could be used as a small unit individually. They are square and can be left on their sides with the photovoltaic panel facing the sun. To charge the switch must be in the “on” position, then when the sun goes down they come on automatically.

Separate lights, panel side

Either way this type of solar light is cheap to buy and easy to use, although one small LED doesn’t light up much. They work well where you need light to move around, especially in a small room where they provide enough light to do what you need to do. One by itself works well in a toilet and two work well in a bathroom or laundry room. I bought four and even when they are all on together they only provide enough light to allow safe access in the lounge room or larger bedroom. Although all four in a smaller bedroom allows you to do some stuff but reading and fine work is out unless you want severe eyestrain.

Separate lights, bulb and battery side

One issue is that they provide a fairly intense point source like a candle rather than the more diffuse light from a fluorescent or incandescent bulb which we are used to. Speaking of candles, did the old put-the-round-wine-glass-full-of-water-in-front-of-the-light-to-increase-the-beam trick. While it did provide a narrow beam which could be directed onto something to highlight it, the beam itself did not light up the room any better.

I also tried putting all four lights in front of a mirror to reflect the light back into the room, it also didn’t seem to do much. So I put some diffusers over them to improve the light, one from the original garden light set-up and one from a caravan 12 volt fluorescent light. The only effect seemed to be to reduce the amount of light put out into the room. The only thing which did seemed to improve matters was to place a sheet of white cardboard or paper behind the lights. It not only reflected light into the room but scattered it so that the light level actually seemed to improve.

Sunnan Solar Light

These are available pretty cheaply (about $20) from Ikea and are a unit with three light emitting diodes in a flexible lighting head that curves around and down to a base which contains an integral solar panel and battery unit. This unit provides the weight to keep the light upright and can be removed from the base and placed in the sun during the day to charge. A friend of mine has even made a frame out of wood to keep the units at the right angle so that they get the most out of the light when facing the sun. You can get a couple of nights use on a day’s charge.

Sunnan light

They are ideal for task lighting such as reading, sewing, typing on a keyboard or preparing food. They provide quite bright light over a small area, say a diameter of 30-60cm. They can be carried with you also to facilitate moving around. We have a couple and find them to be very handy, our daughter even had one set up in her bathroom when the overhead light blew.

Solar panel and battery pack removed for charging

Solar Shed Lights

These come in various sizes and shapes and are composed of a small solar panel which is connected remotely by wire to a light (usually LED) which has a built in battery and an on/off switch. The idea is that the solar panel is mounted permanently outside the space you want to light and the light/battery combo is mounted inside with the wire being fed into the building to connect the two. If you can get access to an area of sun close enough to a window, door or other access these are a good idea.

One type of shed light

While they are designed to remain wired in place, if the area you need light does not provide access from outside or a sunny area for the panel to charge from you can still remove the whole assembly and place the panel in the sun outside. Once the battery is charged outside, bring the assembly back inside and mount the light where you need it. It is more of a pain to operate this way but will still work.

Another type of solar shed light

Another option is to secure the panel in an appropriate place (full sun for as much of the day as possible). There is usually a plug and socket join in the wire somewhere between the panel and the light so you can connect up the light during the day to charge and then unplug it and take it inside for use at night. The light generally has some slotted screw holes (keyhole in shape) on the back used for mounting the lighting assembly. By affixing some screws to the wall or furniture, you can mount the light where it will do the most good.

The one I have has 10 LED lights and cost me less than $15. It is reasonably bright and allows for moving around and doing stuff like washing up, food preparation and eating plus possibly playing games depending on where the light is mounted. It does not produce enough light to read by if mounted to provide room illumination but if mounted a couple of feet from the book you could read by it.

An Integrated Approach

Each of the different types of solar lights have their merits and drawbacks so it makes sense to have a number of each. The solar garden lights can be useful in the smaller rooms like bathroom and toilet and to allow movement through hallways. The Sunnan lights are great for task lighting so you can read or sew in the evening, whereas the shed lights provide better lighting in the larger rooms and where more light is needed for food preparation, cooking and eating.

All of the lights are comparatively cheap and for less than $100 you can have a basic system that will help you move away from the power company and generate your own power, for lighting anyway. This will reduce your electricity costs, eventually paying for itself, as well as improving your carbon footprint and the neighbours will be jealous of you next time the power goes out!

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