I. BATTERY TYPES
Battery consumption depends on the pattern of use. In particular, it takes many times the power to talk as to listen. From conversations with several people using these radios at the Wyoming Gathering, I surmise that a typical user who listens most of the day, talks sparingly and turns the radio off to sleep will consume about one set of AA alkaline cells per day. I will consider this to be "normal usage"; people whose usage differs greatly from this should adjust the figures I present here to conform to their use.
The radios are designed with AA alkaline cells in mind; AA alkaline cells are the most convenient to use. Alkaline cells hold more charge in a given size cell than any other inexpensive cell type. Yet there are problems with our using them.
The first problem is the expense. The Radio Shack price for a two-pack of AA alkalines is $1.69 (catalog #23-557) and for a twelve-pack is $6.99 (#23-652); they can be usually located for $1.50 to $2.00 per four-pack along Canal Street or Fourteenth Street in NYC. Since the radios take eight cells, a set costs $3.00 or more. Assume one day per set and multiply by the number of days at the Gathering; the cost becomes considerable. The second problem, a consequence of the first, is that because of the expense people fail to bring enough batteries to the Gatherings. Towards the end of the Gatherings, we often are faced with a combination of dead radios and runs to buy whatever batteries are available locally, whatever the price. Finally, though Rainbow takes great care in waste disposal, any battery that may happen to be disposed of improperly contributes ever so slightly to the growing pool of toxins in the environment.
[Note: In practice, a battery that will deliver 5 amps for 1 hour will deliver 1 amp for slightly more than five hours. Strictly speaking, when rating the capacity of a battery, along with the amp-hour capacity a "discharge rate" must also be specified. The capacity of a battery decreases with a decrease in temperature; batteries are usually rated at 25 C. (= 77 F.).]
In terms of amp-hours, the consumption of one set of AA alkaline cells per day is about 2 amp-hours per day. Here I emphasize that only alkaline cells have this great capacity. Other common non-rechargeable cells, despite appellations such as "heavy duty" or "long life" have less than half the capacity of alkaline cells for the same size cell. The standard Ni-Cad rechargeable cells have about a quarter the capacity per charge as alkaline cells.
Sometimes small batteries are rated in milli-amp-hours, i.e. thousandths of an amp-hour.
The standard AA Ni-Cad cells are rated about 0.5 amp-hours and are two for $4.69 (#23-125) from Radio Shack or ten for $18.50 for generic cells from All Electronics. Somewhat higher capacity Ni-Cads are also available at a higher price like the Radio Shack 0.85 amp-hour cells for $5.99 each. But even with these higher capacity cells three sets would be needed to last the day. The performance of these cells is still not good enough to ameliorate the problem.
A further problem with AA Ni-Cad batteries is the suddenness with which they die. With alkaline batteries, the voltage drops slowly as the batteries are consumed. You can hear the batteries getting weak before they die. Ni-Cad batteries give near constant voltage until they are almost completely discharged and then the voltage drops sharply. With small AA cells, the resulting interruption is like getting cut off during a telephone conversation.
In shopping for C and D Ni-Cad cells pay careful attention to the capacity rating. The so-called "standard" C and D cell Ni-Cads both have capacities of only 1.2 amp-hours, far below the capacities of the high-capacity varieties. [Note: the old "standard" Ni-Cad D-cells were simply C-cells embedded in a larger shell.]
To contain the batteries, you will have to manufacture some sort of battery holder. I haven't ever seen a battery holder for ten cells offered for sale, but a ten-cell holder can be built from several smaller holders. For example, Hosfelt Electronics offers a four C-cell holder for 50 cents, three of much can be combined to make a 10-cell holder. Alternatively the cells can be soldered together to form a single battery pack. A soldered pack is more compact to carry and lighter as well. For ease of charging, making two 5-cell packs is preferable to one 10-cell pack. Alternatively, ten cells can be soldered together with a DPDT switch that can change them from ten cells in series adding up to 12 volts to two parallel strings of five cells for convenient charging. Soldered packs are more convenient but dedicate the cells to one particular use; loose cells in a holder are more cumbersome but allow the cells to be removed for use in flashlights and other applications. Both systems will work; the choice is a matter of individual preference.
The 4 amp-hour Ni-Cad D-cells have ample capacity for our purposes. They have the capacity to last the typical user over a day without having to drain the last bit of juice; a conservative user might go two days on these cells between charging. The 2 amp-hour C-cells are lighter to carry and less expensive but may fail to last the heavier users a full day. Yet people who use their radios lightly or people who don't mind occasionally recharging their batteries twice per day might find C-cells adequate.
In conclusion, an external battery pack composed of high-capacity Ni-Cad flashlight cells can provide enough power for our needs and is not too cumbersome to carry about. The chief drawback is their high initial expense. New Ni-Cad cells should be able to take at least 500 full charges and can last for decades if stored away from heat while not in use. In the long run, they are cheap, much cheaper than alkaline cells, but the expense for many years of use must be borne up front.
The alternatives to new Ni-Cad flashlight cells are used Ni-Cad flashlight cells, non-standard size Ni-Cad cells and lead-acid cells. Each of these alternatives has disadvantages but is less costly.
The big question is how much life is left in these cells. In truth, nobody really knows. Unlike lead-acid cells, whose performance deteriorates slowly with use and over time and whose remaining life can be estimated through simple performance tests, the performance of Ni-Cad cells is about constant through most of their lives and then drops sharply at their time of death. If a cells is already in the throes of death, a simple test of its capacity will reveal this fact; otherwise there's no simple test to determine whether a cell has most of its life remaining or if it's just about to enter it's terminal decline.
Used Ni-Cad cells can come on the market for a variety of reasons. If they are sold because they no longer perform adequately, then a simple test of the cell's capacity will reveal this fact; the buyer can protect himself against this. If the cells were removed from a piece of equipment that either broke or became obsolete, then there's no telling how worn the cells are; they could be almost new or almost gone. The worst scenario is that the cells were removed from functional equipment because the user believed they were nearing the point of failure; batteries with less than 10% of their life remaining may still possess their rated capacity. But even here, the seller probably doesn't have an accurate count of the number of charges the cells received and is instead estimating by the time the cells were in service that there is a chance they soon will fail.
So used Ni-Cad cells are a grab bag; the seller doesn't know much more about the condition of a particular set of cells that he's selling than the buyer. It may take some luck to get a set that lasts half as long as a set of new Ni-Cads would, but how many casual users ever recharge their cells anywhere near the 500 times that Ni-Cad cells can be charged? Even if a set of Ni-Cad cells are charged only 25 times they still save money over non-RECHARGEABLE cells.
If Ni-Cad cells test their rated capacity at the start of a Gathering, you needn't worry about total failure before the end. If the cells start to go during the Gathering, you may have to recharge them more often, but their decline isn't fast enough to render them useless within a month.
If you get an ammeter and test your cells, it would take a real stroke of bad luck to find a cells that tests at its rated capacity and doesn't last for at least 50 chargings; I strongly recommend testing all used cells. All Electronics has a liberal return policy; you can return any cell that doesn't pass the capacity test. My own experience with used cells is limited to two 4-packs of AA-cells. Both these tested better than 0.6 amp-hours; since I've not had them a year, I cannot yet comment on their longevity.
If you don't have the cash to get a set of new Ni-Cad cells, then consider a set of used ones for a start. Trying a set of used cells may also be good if you're unsure what size cells will best suit your pattern of usage. If you're unsure of whether C or D-cells are better for you, first try a set of used C-cells. A Gathering or two will reveal whether you really should have gotten D-cells instead.
For example, C&H Sales in Pasadena, California offers a "military surplus" 6 amp-hour 28-volt Ni-Cad battery pack for $100. This 28-volt pack is presumably composed of 24 1.2-volt cells which can be broken into two 10-cell packs with four cells left over. The resulting 10-packs are cheaper than 10-packs of D-cells and have about one and a half times the capacity.
This would seem to be a bargain, but needs further investigation. C&H Sales has a stiff return policy including a re-stocking fee; the person I once spoke to on the phone didn't want to answer questions. There are several possible hitches to the offer. First, though the cells are advertised as "unused", if they've been sitting around a warehouse for decades, they may not have much life left in them. Second, though battery packs normally can be broken apart and re-configured, there may be something about this particular pack which precludes this.
Yet this would seem to be enough of a bargain to be worth having someone in Southern California stop by and investigate it to see that the batteries can be reconfigured into 10-packs and aren't too old or otherwise suspect. After all, if we purchase five of these 28-volt batteries (120 cells in all) we can have twelve 12-volt 6-amp-hour batteries at a cost of $41.67 each.
Other deals on non-standard Ni-Cad cells are offered from time to time. Though some of these may be good buys, approach them with a spirit of caution.
With Ni-Cad cells twelve cells in series would produce approximately the same voltage as ten alkaline cells. There's no obstacle to adding an extra two cells to an external battery pack. In fact, you can keep adding more and more cells until you blow your radio.
Experimenting with higher input voltage does involve risk. An automotive electrical system, though nominally a 12-volt system, doesn't remain at an even 12 volts but fluctuates about that value. During charging, the system's voltage often reaches 15 volts and short spikes of higher voltage are also possible. So a radio made to run on an automotive system must be able to handle voltages above 12 volts. One way to do this is to include a voltage regulator, a device that in effect, reduces the voltage to an acceptable level by dissipating the excess as heat. A radio with such a regulator will not respond to higher input voltages by broadcasting with a stronger signal. Alternatively, The radio can be made with circuitry able to withstand more than 12 volts, but how much it can take is open to question.
So be careful when playing with higher input voltages; the radio you ruin may be your own. What works with one radio may blow another. Using 10 alkaline or 12 Ni-Cad cells doesn't yield voltages above what is to be expected from an automotive system and seems to work at least with some radios, but be really cautious about using higher voltages than this.
[Note: Though the nominal voltage of an alkaline cell is 1.5 volts, a new alkaline cell will measure about 1.6 volts; the nominal voltage of a Ni-Cad cell is 1.2 volts but a fully charged Ni-Cad cell will measure 1.35 volts or even 1,4 volts if freshly removed from the charger; the nominal voltage of a lead-acid cell is 2 volts, but a fully charged cell will measure 2.15 volts or even 2.2 volts if just charged.]
Of the two varieties, the deep-cycle batteries fit the Rainbow pattern of use. Yet we cannot ignore motor-starting batteries which sometimes can be had for the asking from a broken motorcycle or whatever. The key to using a motor-start battery is to recharge it frequently, if possible refraining from discharging it more than 25% of capacity before charging it again. Once in a while it can be discharged further, but not too often.
If you happen to have a extra motor-start battery then give it a try, but if you're going to buy a battery get one of the deep-cycle type, even if it costs a bit extra. Lead-acid batteries vary greatly in quality; hope that the seller gives you accurate information about the battery's shelf life, cycle life and other points of comparison. Though you may economize and use a lead-acid battery for a start, eventually you will want to switch to the longer-lasting more convenient Ni-Cad cells.
Batteries can be damaged by excessive charging current in two ways. First, while the battery is charging, a very high current can produce enough heat in a cell to damage it. Second, once a cell is charged, continued application of a lesser current can cause damage.
Two systems of charging Ni-Cad cells may be distinguished. Slow charging is charging at an hourly rate of a tenth the capacity of the battery or less. For example, with a 2 amp-hour cell, charging with a current of less than 0.2 amps is called "slow charging". Slow charging uses low enough currents so the cells will not be damaged, even if left in the charger for some time after they are fully charged. [Note: Even though a few hours of overcharge will not harm cells, its better not to go on charging cells indefinitely.] Inexpensive battery chargers are generally of this type. Charging at greater currents, which can potentially harm a cell if continued after the cell is charged is called "fast charging".
Of the two, slow charging is easier and safer. Slow chargers are easy to build and inexpensive battery chargers are invariably of this type. But at the Gatherings, radios are used almost continuously; with slow charging two sets of cells would be needed per radio, one set in use while the other is being charged. Since the expense of Ni-Cad cells is the primary obstacle to using them, we can expect that some radios will come to the Gatherings with only a single set of cells. For these radios to operate most of the time, fast charging is a necessity. So we must be prepared to do both slow and fast charging.
Continuing with the example of a hooking a dead 6-volt battery to a charged 12-volt battery, suppose both batteries have the same capacity in amp-hours. At the end of the process, the 6-volt battery will be charged and the 12-volt battery will be dead. [Note: In practice, there's always some loss due to gassing and such; the 12-volt battery will have to be of slightly greater amp-hour capacity than the 6-volt battery in order to fully charge it.] Since the energy stored in a battery is its amp-hour capacity times its voltage, the charged 6-volt battery will have only half the energy that was in the original 12-volt battery; the remainder will have been dissipated, primarily as heat. Despite this 50% energy loss, something useful may have been accomplished: for example, the 6-volt battery may be portable while the 12-volt, not.
Now suppose that to a 12-volt battery, we connect, with appropriate resistance a single 1.2-volt Ni-Cad cell. The Ni-Cad cell will charge but the energy gained by the Ni-Cad cell is only a tenth of that lost by the original 12-volt battery. This 10% efficient charging system sounds terrible, doesn't it? Yet the commonplace Ni-Cad battery charger sold for use with automotive systems, the one with a lighter plug and a box with slots to hold up to four cells, works this way. Since the cells are placed in parallel, the efficiency of this unit is 10%, no matter how many of the four slots are occupied.
This inexpensive but inefficient unit is fine if used only to charge a few cells once in a while and if the vehicle's motor is run before too many uses. But suppose that this sort of charger is used to charge a set of ten 2-amp-hour Ni-Cad C-cells, which would last the typical user about a day. Charging each of the cells would drain 2 amp-hours off the source battery; charging the set of ten would require 20 amp-hours. The capacity of many smaller car batteries is not even this much. [Note: In advertising their batteries, manufacturers state in amps, the current that the battery can deliver for a short time, not the capacity in amp-hours. Since this spurt of current cannot be maintained for an hour, the current deliverable in amps is a much higher number than the capacity in amp-hours.]
Suppose instead that the ten Ni-Cad C-cells are broken up into two sets of five connected in series. In this configuration, the same current passes through five cells. Each charging each set of five cells takes 2 amp-hours so charging all ten cells takes 4 amp-hours. With this configuration, even the smallest automotive battery can charge the set without draining itself excessively. For reasons such as this, it is best for us to make our own battery chargers. If we put a little thought into how we do out charging, we can make do with the smallest number of charging sources be they car batteries, solar panels or whatever.
Charge ---> Fuse---> Resistor ---> Battery ---> Ground Source Bank Bank The charge source can be any Direct Current source: carbatteries, solar panels and whatever. The battery bank can consist of any number of cells arranged so that the voltage of the battery bank is 25% less than that of the charge source. Suppose that a bank of 10 Ni-Cad cells is to be charged. The nominal voltage of each cell is 1.2 volts or 12 volts if the entire set is configured in series. If the charging source is a 12-volt battery, then the 10 Ni-Cad cells must be broken up into two parallel banks of 5 in order to charge. On the other hand, the typical solar panel in home systems gives 16 to 17 volts and can charge 10 Ni-Cad cells in series.
The resistor bank controls the rate of charge. The resistance of the bank can either be fixed or variable. The current passing through the resistor (in amps) and its resistance (in Ohms) are related by Ohm's Law:
Voltage = Current x Resistance
where the voltage is the voltage across the resistor (in volts). In our simple charger the current may be measured by including an ammeter in the circuit, but ammeters have the disadvantage that they must be wired in series. It's easier to measure the voltage across the resistance and calculate the voltage than to bother with an ammeter.
Ohm's law is also used to calculate the resistance needed. For example, let us suppose we are to slow-charge a set of ten 2-amp-hour Ni-Cad C-cells at a rate of 0.2 amps, using a 12-volt battery as the charging source. We must break the ten cells into two series of five; since each series is to receive 0.2 amps, we need to deliver 0.4 amps. When fully charged, the cells will have a potential of about 1.5 volts or 7.5 volts for five in series. If the 12-volt battery is fully charged it may have a voltage of a bit more than 12 volts, figure on 12.5 volts. Thus the difference in these two voltages 12.5 - 7.5 = 5 volts will be the voltage across the resistor. Using Ohms law:
5 volts = 0.4 amps x resistance
we calculate a resistance of 12.5 ohms; with a resistor of this value we will have a battery charger that will charge this particular set of cells in 10 hours or so. Leaving the batteries charging for longer won't harm them but it will keep draining the source battery. So if you intend to return to the charger for fresh batteries once per day, you might instead opt for a 25 ohm resistor which will take 20 hours, twice as long, to charge these cells. At this lower rate of charge, less is lost if you fail to return to the charger on time.
Once the arithmetic of Ohm's law is understood, we can simplify the situation. It's a good idea to be able to monitor the current. Suppose that we include in the circuit a 1 Ohm resistor, in series with the rest. Across a 1 Ohm resistor, the current equals the voltage. If a voltage meter is placed across the resistor we can read the current directly, without having to wire an ammeter in series. Since the voltage meter doesn't have to be wired in, one meter is enough to monitor all chargers in the vicinity. The least expensive digital multi-meter in the catalogs I get is from Hosfelt Electronics (#29-102) costing $16.95. I have ordered one and it works fine. Though analog voltage meters can be had for less, a digital meter is more convenient and has other functions as well.
A fixed resistance charger may be good for a start, but even with slow charging, sometimes we may wish the batteries to charge in 10 to 12 hours while at other times we may want them to charge in 20 to 24 hours. We may sometimes wish to fast-charge our cells in which case we must be able to carefully control the current we pass through them. The solution is a variable resistor or rheostat. Here it is essential to have a 1 Ohm (or other known) fixed resistance wired in series to the variable resistor. First, the 1 Ohm fixed resistance provides a convenient way to measure the current and second, the fixed resistor in series provides some safety against accidentally turning the variable resistor to zero and sending a huge current though the system.
A few words need to be said about fast-charging Ni-Cad cells. Ni-Cad cells can be charged rapidly, in an hour or even less if you make sure to stop the current once the cells are fully charged. The problem is to know when the cells are charged. As cells near full charge, their voltage rises. The trick is to keep the cell voltage less than 1.6 volts per cell; as the voltage approaches this value, increase the resistance to reduce the current. It's best to measure the voltage of each cell individually.
The simple charger can be made more sophisticated if you wish. One useful addition is a relay to reduce the current to a slow rate once the voltage reaches a certain level. A really sophisticated charger will use pulses rather than resistance to regulate the current. Such a charger could be made to be very efficient, but a simple charger is enough for our present needs.
Resistors can be bought or found on old equipment. Any coil of wire is a resistor; old motor coils and heating coils make excellent resistors. Make sure that the resistors you use can handle the currents you will use. The quarter-watt resistors found on circuit boards are too small. Figure on at least 5 watt resistors for a slow-charger and 50 watt ones for a fast charger. or calculate an appropriate value. Do include a fuse in the circuit for safety; electrical fires can be spectacular.
At the Gatherings, the norm is that people park their vehicles and stay a while. The number of vehicles is many times the number of radios, but unfortunately, it's impractical to arrange access to everyone's car battery. A car's battery can be recharged by running the engine, but this is polluting and inefficient. Solar-electric panels are likely the best alternative source of power.
At the Wyoming Gathering, one bus was parked with it's entire roof covered with an impressive array of solar panels; several had a panel or two on them. These could have answered all our Ni-Cad charging needs with a fraction of the power they could generate. If we don't wish to rely on a bus with panels showing up, it's not that difficult to dismantle somebody's home solar-electric system, batteries, regulator and all, and set it up by the road. Alternatively, one could borrow a single solar panel and use it to keep a car battery near full charge. A relay can provide a simple regulator good enough for the purpose. The panel need not be a full-size one, but the extra-tiny ones, sold for battery maintenance, which sit one the dashboard, are too small to sustain round-the-clock battery charging.
One way or another, it's not all that difficult to charge our cells at the roadhead; in a pinch, we can always run a motor. But for many of us, the fewer trips we make down to the road, the more enjoyable is our stay at the Gathering. So we must be able to recharge our cells in camp as well.
The panels are the pleasant part of a home solar-electric system. They last for decades and require no maintenance. The beast of a home system is the battery. Batteries are usually of the lead-acid type which need care and periodic replacement. The open-vented batteries last much longer than the sealed batteries. Modest home systems use batteries sold as "golf cart" or "fork lift" batteries. Even the smallest common battery of this type is a 220 amp-hour 6-volt battery weighing 65 pounds, two of which are needed in series for a 12-volt system. Thicker plate, longer life batteries weighing over a hundred pounds may be more popular. These batteries, filled with sulfuric acid which could leak if you trip, are hardly a pleasant backpack load. They would better be transported slung from a pole and carried by two.
One alternative is these heavy batteries is to charge our Ni-Cad cells directly from the panels. This would entail bringing more panels than if we had a storage battery at the charging site. At times, several people might need to charge their cells and we might not have enough power from the panels to do this, especially if the day is cloudy; at other times excess power from the panels would go to waste. No charging would be possible at night.
The other option is to use lighter batteries. Sealed deep-cycle lead-acid batteries of smaller size are sold as "RV-Marine" batteries. The implication of this name is that they aren't made for daily use; they will last perhaps 500 cycles, while the life of the heavier vented batteries is somewhere in the thousands of cycles, depending on the quality of the battery. Yet some people buy these cells for home power systems, though they're likely to replace them with longer life batteries the second time around. These easily portable batteries would be good for the camp. Otherwise, we could resort to using automotive batteries. With automotive batteries, we should aim to avoid discharging the batteries more than 25% of capacity, though an occasional deeper discharge on a cloudy day won't cause catastrophic damage.
A charge-controller is needed to keep the panels from overcharging the storage battery. If we can't get one from someone's home power system, an inexpensive but adequate controller can be made from a relay.
One thing to consider is the solar-electric car, which is a self-contained, mobile power system. Solar cars are home made contraptions, coming in all shapes and sizes. Though some are converted from small gasoline cars, others are real lightweights which roll on bicycle tires. The lightest of these are far less than the horse-drawn wagon that made it to the Wyoming Gathering. Other sites we may choose might have more rugged access paths, but if the vehicle can roll most of the way by itself, a bunch of people should be able to lift these lightweights over wet spots and rough spots. People who make solar cars often like the opportunity to display their contraptions and the Gatherings are fine places to show them off.
B. Hydroelectric Generators. Small hydroelectric generators are the least expensive home source of electricity for people with a suitable site. They're small and light. The pipe they require is much heavier than the generator, but at the Gatherings, we have been hauling in pipe for the drinking water system. The Wyoming site did have enough water flow to generate a useful amount of electricity, but we might not wish to confine our choice of Gathering sites to those with hydroelectric potential.
Where we have a suitable site, small hydroelectric generators are a practical power source. They generate electricity at a steady rate, day and night, cloudy and clear, which alleviates the need for a storage battery. Along the Pacific Coast with its winter rains, people use hydroelectric power to supplement solar power in winter; these generators are idle in the summer and perhaps available for our Gatherings.
C. Wind. Though solar panels still produce some electricity on overcast days, on a calm day a wind generator produces nothing. Wind is too unreliable to be our main source of electricity. If someone wants to haul in a small wind generator that's fine as a supplement to other power sources. Wind generators work best on a tall tower, both to catch increased velocity and to avoid ground turbulence, but a ground-level generator will produce plenty of power on a breezy day.
D. Wood. One energy source we have much of at the Gatherings is firewood. Unfortunately, there is no ready system for converting it to electricity. A few years back I investigated the possibility of a small steam generator for my home but found nothing suitable is now made. There's a great gap between classroom demonstration models, too small to produce useful power and the smallest commercial engines, heavy machines with outputs in the kilowatt range. I also investigated the possibility of making my own. An efficient steam engine requires high steam pressures with the consequent dangers, but I didn't require efficiency. With all the wood I burn to heat my house. 0.1% efficiency would be more than enough. At this level of operation with a turbine design, pressure cooker level pressures and seals would be adequate. The problem was that I couldn't find a reasonable supply of parts for the project. Without access to a good machine shop, I dropped the idea. A low pressure steam turbine might be a nice engineering student project; the surplus heat could warm our showers.
The other possibility for converting firewood to electricity is the thermo-electric cell. When one end is heated and the other is kept cool, these cells generate electricity. Thermo-electric generators are available which use catalytic propane burners for heat. They serve for remote electrical equipment in arctic regions. The problem with trying these cells with wood heat is temperature regulation. There's a narrow range of temperature at where these cells produce useful amounts of power before they melt. With catalytic burners, regulating the flow of propane can keep the temperature fairly constant within this range. Though thew temperature of a wood stove can be regulated through a thermal control on the draft, the regulation is not nearly as good. Though thermo-electric units for wood stoves have been marketed, none of them has proven to be any good. Steve Willey of Backwoods Solar Electric has experimented greatly with thermo-electric power; consult him before investing in any such equipment. If the thermo-electric cells is improved, in the future it might provide a silent dependable source of electricity.
E. Human Power. Bicycles can be mounted to turn small DC generators. For a while racer can put out 100 watts; ordinary mortals, pedaling at a steady pace put out about 30 watts. At this rate, it would take about an hour of pedaling to put a day's worth of charge into a set of radio batteries. I would think this is too much effort, but if people are willing to put in pedalling time, bicycle generators are easily built, light, inexpensive and reliable.
Anyone wishing to engage in fantasy is welcome to submit designs for a dog treadmill generator; round up all the loose dogs which terrorize our camp and make them make electricity.
F. Gasoline Generators. The commonplace small generators put out 120 volts AC and require a battery charger to convert to DC current. It's much more efficient to generate DC directly by having a small motor turn an automobile alternator; this design is available from some solar dealers as a kit. Though gasoline generators may be the path of least resistance, they are noisy and polluting; I for one would object to them in camp.
In camp, battery charging would likely be part of a larger electric system. It would be nice to replace some of the fossil fuel lanterns with electric lights. Yet we should proceed with caution. Our camp is already more of a city than we like to think; electrification would make it even more urban. Lighting should be kept to reasonable levels and sound amplification prohibited. With electric motors, though I would have no objection to a kitchen running a small quiet electric juicer, I wouldn't like to have to listen to an electric saw. As we admit electricity into our camp we must exercise care to see that it improves the environment, not degrades it.
The people who stay longest at the Gatherings should take the lead in obtaining rechargeable batteries. If you come to set up camp and leave after cleanup, the savings of not using alkaline cells should pay for a set of Ni-Cad cells even in the first year.
Once we have rechargeable cells, the charging sources will appear. At first, we can use car batteries, but eventually we should have charging sources in camp. As a start we should take inventory of the solar-panelled busses in the parking lots. If these seem inadequate, we can solicit for people with home solar electric systems to see who would be able to bring panels to future Gatherings.
We don't have to completely eliminate the use of alkaline batteries. Some alkaline batteries should be kept for emergency use. The Wyoming fire showed how a crisis can disrupt camp life and likely interrupt battery charging for the duration. But alkaline batteries have a long shelf life. We should hope that our emergency reserve of alkaline cells does not get used and can serve as our reserve for the next Gathering.
To encourage people to work out the best solutions for themselves, I have avoided making specific recommendations. Yet for someone with limited resources who isn't sure what to do and but would like to make a move to using RECHARGEABLE cells, let me suggest getting a set of 10 used Ni-Cad C-cells from All Electronics for $20. Get a resistor in the 12 to 25 Ohm range to make a slow charger. Even adding a fuse, some clips and connectors and postage, the project shouldn't set you back more than $30. If you have a friend with a meter to test the batteries and other components, you don't need to get your own meter. These Ni-Cad C-cells have about the same capacity as alkaline AA-cells; if you use them ten times, you've recovered your money. Charge the cells before arriving at the Gathering, but bring a reserve of alkaline cells as well. Use the Ni-Cad cells first. Then use the alkalines while hoping for a chance to recharge. If you do get back to the road, recharge the Ni-Cad cells off a car battery; otherwise see if a solar panel or something shows up in camp. Not at the very next Gathering but certainly within ten Gatherings you'll have recovered your investment.
Summarize the essential characteristics and performance of available battery types in a clear and concise manner. The lack of substantial improvement in batteries leaves this 15-year-old publication still current.
Home Power Magazine (Bi-monthly) P.O. Box 520, Ashland, OR 97520
A magazine to promote the consumption of alternative energy products rather than to critically discuss and develop the field. Many articles are scientific monstrosities with errors up to and including the violation of the law of conservation of energy. Yet the magazine also prints some fine articles. You can learn from it if you have enough scientific background to distinguish what is real from what isn't.
The main use of this magazine for us is as a source of contact. The magazine does print letters and would likely print an appeal by us for bringing power generating equipment to the Gatherings. Since many alternative energy dealers advertise in it, the magazine is a useful source for anyone wishing to purchase solar panels and other such equipment.
These outfits offer batteries and electrical components. All have 800 phone numbers and will send you a catalog for free. Though these catalogs don't cost money they do cost trees, so share them if you can. And don't forget Radio Shack whose ubiquitous retail stores do stock components and well as consumer electronics.
Don Harris (Harris Hydroelectric Systems, 632 Swanton Road, Davenport CA 90517) manufactures small hydroelectric generators and is a source of information and contact with others.
Northeast Sustainable Energy Association (23 Ames Street, Greenfield, MA 01301) among other things sponsors electric car rallies and is a contact source for this region.
Michael Hackleman (Earth Mind, P.O. Box 743, Mariposa, CA 95338) once published a magazine "Alternative Transportation News" and is a source of contact for solar cars and such.
John Wiles (Southwest Technology Development Institute, Box 30001; Dept. 3SOL, Las Cruces, NM 88033-0001) once sent me a copy of the Battery Handbook mentioned above. Though not such a likely person to show up at a Gathering, he is excellent on the more technical aspects of alternative energy.
These people do respond to questions, but to get the most from them, think your problem through and make your questions clear.
Finally there's myself. I'm leaving shortly for India and won't return until May, but after that I will be around to help as I can including the assembly and testing of equipment.