This section is included because energy autonomy is important for community run communication networks.
Many designs of wind generators are available. Magnets from microwave ovens can be used. These are usually set into resin to stop them flying off which can be very dangerous. Static coils and moving magnets get around the problem of needing brushes like in electric motors. The blades can be carved out of hard wood.
Car alternators have often been used but they are a bad choice as they give no voltage at low speeds and so need gearing. Belts from tractors (UK supplier for the tractor belts) have been used between the rear bike wheel and the alternator. However DC motors give much better results. These can be bought new but are expensive. Car windscreen wiper motors could possibly be used.
tim's pedal generator using dc motor and cycle training stand (originally on leeds-alternative-energy wikispace which has now been deactivated).
For a mini version, stepper motors from printers and other electromechanical devices will give AC power at very low speeds. It can be interesting to play with leds and turning the motor by hand. They have multiple sets of coils, to allow the printer to make high-precision movements, which is why they have so many connections, and you will need to experiment to find which pins can be connected together to a to a bridge rectifier of four diodes to give maximum DC output.
Hub dynamos are small generators in the centre of a bike wheel, used to create power whilst cycling, which traditionally was done by a DC dynamo in direct contact with the tyre. They often produce AC and are usually used for powering lights, but can be used for other things too, such as amplifiers or radios.
Solar panels are a simple and robust power solution but their production is energy-intensive and polluting. They can be stolen quite easily but there are roumours that some contain hidden chips which can be used to track their position.
Maximum power point tracking (mppt) regulators are more efficient but expensive. Cheaper 'PWM' regulators will allow the battery state to determine voltage which may not be the most efficient for the panel. MPPT regulators use a control circuit to 'search' for the voltage allowing the highest power output.
Another advantage of MPPT regulators is that it is possible to charge a 12v battery from 24v panel or potentially a 24v battery from a 12v panel (works with for example 'emponi sol1').
Note that some regulators sold as 'MPPT' are not actually MPPT. Read reviews of the model you are considering buying, particularly if it seems cheap. True MPPT controllers can usuallly be identified by a large inductor in the circuit.
Of course when using solar panels it is better to use electrical appliances during the day when more power is available. The cheaper regulators will even cut out and stop charging the battery when the voltage goes too high (when its very sunny), so its good to have something connected to use the extra power if this is the case.
If using inverters, it is usually better to connect them to directly to the battery rather than to the 'load' ouput terminals of the solar controller. This is because inverters will usually have their own system of switching off in the case of voltage becoming too low, and they are designed to be switch at such high currents. Allowing the controllor itself to switch such a high load could damage it, especially if it is a cheap one.
When buying an inverter, it is worth looking for a 'pure sine wave' one, but it is hard to know if it is really pure sine wave without testing it with an oscilloscope. Many cheaper inverters will work fine running lights and power tools, but will not work well with electronics, charging laptops etc. It can be better to simply use 12v DC (car) adaptor for laptops, phones etc.
12v DC soldering irons, which can be run from batteries, are available. But for situations where you do not have enough power to use an electric soldering iron, a butane gas powered soldering can be used (eg:'Power probe'), which can be refilled just like a butane cigarette lighter. A simpler, but considerably less effective solution could be just to heat nails in a fire and use pliers to hold them for soldering.
It is also roumoured that pine tree sap can be used to make flux, which is used to make solder flow more freely.
It is best to use 'deep cycle' or 'leisure' batteries rather than car batteries as they are designed to be dischared deeper. However car batteries can be used if they are the only thing available and it is the battery itself which will be damaged by discharging it, not the appliances you attach.
Often batteries can be improved simply by adding distilled water. Open the caps and if you are able to see the tops of the lead plates, you need to add water. Clean rain water can be used if you dont want to buy distilled water. Batteries which appear sealed can often be opened by forcing open a plastic panel to reveal little lids to the individual cells.
Old lead-acid batteries which will no longer hold a charge can be often rejuvinated by pulse charging them to de-sulphate the cells, provided they have not shorted out as a result of a buildup of lead deposits in the bottom of the battery. There are many designs for pulse chargers available. A simpler method is to connect the battery directly to a solar panel to give it a burst of power to desulphate the cells. This should be done with much caution, in best case outdoors, because of the flammable gas which the battery gives off, and of course do not leave the panel connected after dark!
As a last resort, it is possible to use old car batteries which no longer will charge to 12v (which you often find discarded) as 9v batteries, which can power, for example, 3 led bike lights soldered together in series (2xAAA batteries=3v) to get the last bit of use out of them.
Large 180ah truck-style batteries can often be found in tempory traffic lights used for roadworks. However there are roumours that these sometimes contain chips so that their location can be tracked if stolen.
Electric wheelchairs usually use very good sealed batteries. It could be a good idea to try asking at shops and companies who sell or service electric wheelchairs for old batteries.
Security and fire alarms also often have good quality sealed batteries as backup power, these can often be found in abandoned buildings or try asking manufacturers for old ones. The smaller ones will power LED lighting for a useful amount of time and are small enough to carry in a rucksack to charge elsewhere, so perfect for when you have several people sharing one solar panel.
Alum is the stuff deodourant stones are made from. It is also sold as a food additive used to keep pickles crisp. Apparently it can also be used as a water purifier. So it is less environmentally damaging than sulphuric acid. Some people (notably John Bedini) have reported emptying the acid from batteries and refilling them with alum solution. There is some controversy on internet forums about the advantages of alum batteries, it seems it is an area which needs further experimentation. Some say that:
Alum batteries have a longer lifetime. This can be because the lead is not corroded (eventually resulting in a short circuit caused by lead deposits). Also possibly because sulphation of the plates does not occur.
LEDs can be cheaper when bought in strips, for example 5630 SMD white LEDS can be bought in rolls of 5 or 10m, for 12v systems use multiples of 3 LEDs.
When using headtorches, remember when replacing the batteries that they often discharge irregularly, the light will go dim when just one of the batteries is low, so test them with a volt meter and usually you will only replace one of them. This also means that batteries discarded by other people are worth testing.
Small heat powered electrical generators that can be attached for example to a wood burner. They need to be in a position where one side is hot and the other cold. They dont produce a lot of power but could be useful for powering electronics stuff.
wood warms you three times. Once when you collect it, once when you chop it and once when you burn it.
sci.electronics.rapair repairfaq.org how to repair many things.
car amplifier repair basics much information on this site
Soon to be its own page.
ecoconstruction design by mike reynolds, using car tyres to collect the heat from south facing windows. The original three volume earthships book is available on library genesis