The Free Range 'Great Outdoors' Project – The 'Great Outdoors' (O) Handouts
Light and Power
Using micro-power systems outdoors
There are a lot of good things about technology: being able to make light at the flick of a switch is one; getting information and entertainment over the radio is another. This unit looks at how we can generate, store and use electricity outdoors using very small-scale micro-power systems.
A matter of scale
In this unit we look at the options for creating and using electricity outdoors using mobile micro-power systems – human powered and renewable energy systems that create very small (by comparison to your home) amounts of electricity to accomplish limited tasks: making light, running a radio, or charging batteries to put into other cordless devices. There are of course other, more traditional means of creating light, and we'll look at those too.
An awful lot of the information we see about renewable energy, especially renewable electricity, is about replacing conventional mains power supplies with renewable ones. Being outdoors, and trying to be as simple as possible, much of this information doesn't apply. You're not (hopefully!) going to be powering a TV and a fridge and so the scale of power demand is much lower, and this makes generating the power you need easier. More practically your set-up has to be light enough to easily carry, and this will ultimately limit the power that you have available.
Wind-up versus renewable
There's a lot of iconic baggage related to renewable energy. The very concept of “renewable” is often seen as an 'uncontested good', and so by association anything that incorporates renewable energy devices must also be good. In reality this isn't the case. There's a lot of kit out there, from mobile phone chargers to “mobile” (until you try to lift them!) solar suitcases, but not all of it is well designed or functionally useful. The same can be true of wind-up devices, but there is another issue that is rarely discussed; is it better to go for wind-up or renewable?
The reality of renewable technologies is that environmental energy sources are not very 'dense', and so small devices tend to produce very little power. On the other hand (no pun intended) wind-up devices can produce a lot of power for the amount of extra weight you're carrying. From experience, if you're seeking to minimise your use of resources, be it a torch or a radio, wind-up tends to work better for the amount of cost and weight involved. In fact, it's rather sad that human muscle power is the one form of renewable energy that the environmental movement seem reluctant to vigorously promote as an alternative to the "technological” (or lazy!) form of renewable energy.
In this unit we cover both – renewable and wind-up power. Which one you adopt really depends upon your own needs and experiences. However, given that the most simple and portable form of renewable power is solar, if you're camping in Winter, or you're unlucky to have a run of bad weather, you'll probably find wind-up technology more reliable.
The need for light
Wall-to-wall, 24-hour lighting is a Twentieth Century artefact; before that people lived with much less artificial lighting and tended to plan their work around daylight as a result. In terms of the problems with our future energy supply, intense and pervasive lighting will have to be consigned to history because it's just so energy intensive to run. Lighting also has its dis-benefits, the most obvious one being night-time light pollution which denies us our view of the stars.
When camping in the Summer you can get by with no artificial light sources at all. In most of Britain, if you rise at dawn and go to bed at dusk, you can get fourteen to sixteen hours of usable daylight – even more in northern Scotland. And in Winter, on a clear moonlit night you can walk around without a torch. So, considering the availability of usable daylight, in most cases our need for artificial lighting should be designed by necessity, not out of habit.
A small, low powered torch is sufficient to get by in Summertime if you organise yourself around natural light (wake at dawn/go to sleep at dusk). Outside of the Summer the options depend upon how you are organised. For one or two people, especially when trail walking, battery or wind-up torches are sufficient. In Winter you might have a problem because you will be spending more time in the dark. However, as camping in Winter, early Spring or late Autumn usually entails running a small fire for warmth, you'll have a small amount of light as a by-product of your heat source.
For a small group of people, especially if living in a static camp, you're likely to need a little more light. In these situations you might opt for a solar/wind charged micro-power system, as described at the end of the unit. A hard-wired system like this can be easily portable if the components are split up between everyone in the group, but if you're mobile the continual dismantling and re-assembly of the system can shorten the life of some components.
There are all sorts of options to create artificial light (see the box on the left), and each has its benefits and problems. The main issue related to their use is something more practical – weight.
Sometimes weight isn't an issue. Candles and oil lamps are not practical for use in a tent and so you'll probably take a torch – in which case why bother to take the candles/oil lamp as well? But if you're planning to spend some time outside and it gets dark early candles and oil lamps can be a better option than the obvious alternative, a battery lantern.
Electric lighting is better for the restricted space of the tent, but you'll have to carry spare batteries or spend your time winding. However if you set your pattern around the daylight hours you won't need an awful lot of light, and so in these cases wind-up devices needn't be a problem (but they can be damn inconvenient when they run down in the middle of your night-time toilet break!).
When you include the additional cell batteries or liquid fuel, the baseline of efficiency for any source is how many hours use you get. It's important, given the time of year, to try and estimate how much time you're going to need the light source for:
- If you only want light intermittently, and for short periods, then electric or wind-up devices are obviously the solution;
- If you want light for long periods but not inside an enclosed space then any form of light will do but wind-up might become a little tedious (unless there are a few people camping together to share the duty between them);
- If you want light for inside a tent for longer periods then electric lighting is the best source.
A torch is the obvious light-producing device to take but they have a significant drawback; they only shine light in one direction. If you're moving around at night then shining the light in a narrow beam is more efficient to find your way, but in camp the uni-direction beam creates problems, especially when there's more than one person involved. So, if you're needing to walk cross country at night take a torch; otherwise get an electric lantern as the omni-direction light they produce is more useful in your tent, and around the camp.
In Summer lighting isn't essential. If you're taking a trip between the late Autumn and the early Spring then the shortage of daylight makes artificial light more important. Whatever source you propose to take run it for a while before you go and measure roughly how many hours of light you get from it. Then sit down and work out, at X hours per day, how much you need. If you don't have enough time then you'll have to re-think your options.
Options for making light
Sometimes it's nice just to disappear for a few days, and in these cases you might welcome “getting away from it all". However, for longer trips, and for getting useful information such as the weather forecast, having a way of receiving radio broadcasts can be useful. You might also like to play music, and certainly on long, dark Winter nights a little music or a radio programme makes the time between nightfall and going to sleep pass a little more easily.
The options are very similar to lighting – either battery, wind-up, or using rechargeable cell batteries that you take with you. The significant difference is in application. Most low powered music devices use earphones and so only one person can hear them well – whilst the person next door just gets the annoying rhythmic hiss they create. For a group wind-up is clearly the better option because although it will need a little more attention, those sharing its output can take turns to wind it.
Generally, unless you're running a free festival, you don't want to be making a lot of noise – when you're on a site it's usually against the rules, and when you're wild camping it attracts attention. Also the more noise, especially low frequency bass beat, the more power you consume and so the more batteries you must carry or the more you must wind.
Options for making noise
Renewable micro-power systems
Simple renewable micro-power systems don't seem to be easy to find, and in most cases you'll have to put your own together. The reason is that very small systems are not of practical use in the 'modern' home, and so are not developed for the home market. At the same time the camping market tends to focus on bulky gadgets for site campers, and so you don't get very simple and elegant mobile systems.
Most domestic renewable installations, wind or solar, usually have a generating capacity rated a kilo-Watt or more. For a small camp installation, especially if you want it portable, then you're usually looking at a few tens of Watts. That's more than enough to run your lanterns, a radio, and possibly a small cell battery charger – provided that you only use the power as and when needed rather than leaving it on around the clock (often the habit people get into when they're connected to the mains).
The diagram on the right shows the layout of a typical self-build solar power system. Putting together and maintaining something like this takes a little learning and time – and certainly before taking it away on camp you should practise using it at home to iron out any gaps in your knowledge (otherwise you'll be carrying an awfully big lump of dead-weight!).
Developing a small-scale system like this may seem a lot of hassle when there are battery and wind-up alternatives more easily, and perhaps cheaply, available. That's true, but it misses the point of the exercise, and certainly one of the main points about the 'Great Outdoors' initiative; developing something like this gives you the skills and knowledge required to run a house-sized system! Building a system like this for your home is difficult because you might need planning permission for the PV or wind generator, and you'll certainly need Building Regulations consent for the wiring (you must get an accredited electrician, or paying the council to come and certify it for you). Building a system like this for use in a caravan, tent or wild camping trip doesn't require any legal approval!
The main restriction for a system such as this is that it's better suited to a static camp rather than a mobile expedition. For PV, being static is essential so that the panels can face the sun. A small wind generator needs mounting on a short pole, perhaps on a fence post, for as long as possible to catch the wind. In any case, you only need a system like this if you're using a lot of light or you need to charge cell batteries – that's the type of situation which is more likely to happen with a static camp rather than a mobile expedition.
The different elements of the power system shown on the previous page are described in the box on the right. Most home electrical hobbyists could put one together. Once you have the components all that's required is a soldering iron and some wire strippers/cutters.
Describing the precise process of putting a system like this together is beyond the scope of this briefing, but the Free Range Salvage Server Project are working on this kind of guide as part of their forthcoming SSP Power Systems Toolkit. This will be available during 2009 from their web site – http://www.fraw.org.uk/ssp/. Alongside this a day-long workshop, "PV, Batteries and Bulbs – A Beginner's Guide to Renewable Power” is also being developed which shows you how to build this system, and how to scale/modify it for different purposes.
Produced by the Free Range 'Great Outdoors' Project –
© 2008 Paul Mobbs/The Free Range Network. This document has been released under The Creative Commons Attribution Non-Commercial Share Alike License ('by-nc-sa', version 4).