continuing the search for a cheap and easy emergency power system

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Continuing the search for a cheap power system. . . what do y'all think about this? Robert Waldrop

Essentials of a cheap power system

1. A method of charging a battery. This can be the alternator from a car (requires gasoline), a portable generator (can be expensive), or a solar panel (requires sunshine). A small, inexpensive (about $20) solar panel that supplies 1.8 watts and plugs into your car's cigarette lighter can recharge a battery (it takes a while though, additional or larger panels would speed this up, a 10 watt panel sells for about $100).

2. Batteries. You can use a car battery, but marine or golf cart batteries are better. Repeatedly charging and depleting a car battery will eventually cause it to fail, the marine/golf cart batteries (known as "deep cycle" are designed to do this and thus last longer. However, if you don't discharge a car battery more than 20%, you can prolong its life considerably.

3. Inverter. This changes the battery's 12 volt DC power into AC power such as you get from the electric company. A 140 watt inverter costs less than $40, plugs into your car's cigarette lighter, and is available from many electronics stores. The inverter automatically shuts off when the battery power drops & you can restart the car if necessary to recharge it.

4. Distribution. Use a good quality extension cord and a power strip. The extension cord connects the inverter plugged into your car battery with the power strip inside the house. (The battery and cigarette lighter could be brought inside the house from the car.) CAUTION: you must live within your energy budget. A 140 watt inverter will supply enough power for a 60 or 100 watt bulb, but not both of them, it would power a radio, CD player, or a small TV (black & white is best for this). Flourescent lights provide more light for less power, and larger inverters are available (more batteries helps too.)

-- robert waldrop (rmwj@soonernet.com), August 07, 1999

Answers

Robert,

Personally, I think that if you can get by with as little electricity as you're talking about (140 watts or less), you can get by without electricity altogether. Such a small amount of power doesn't justify the expense producing it. Running an auto engine to just recharge the battery is very inefficient.

The 1.8 watt panel you mentioned would hardly keep a battery charged even if you didn't use the battery, much less recharge it. The 10 watt panel would do very little more.

If it's just light you want, use a kerosene lantern, candles, or an oil lamp. For radio power, invest in the Bay-Jen (sp?) freeplay with the crank handle in the side and get radio useage, and one model also has an LED light with it, so you can have both.

Gerald in East Texas

-- Gerald R. Cox (grcox@internetwork.net), August 07, 1999.


Thanks for your critique. The rational for doing this includes:

1. Morale.

2. Redundancy (one more option among several).

3. if people do this, they will learn more about systems and can perhaps step up to something bigger and better (e.g. more batteries, more solar panels).

4. Candles and lanterns do represent fire hazards (a manageable hazard, I hasten to add, but hazards nevertheless.) In my y2k writing, I have had a lot of mail from firemen saying "don't suggest candles or kerosene". I haven't always followed their advice, but it is an issue.

C. Crane company tells me that their 10 watt solar panel will charge a 12 volt battery in 8 hours of sunshine, which I consider to be acceptable. The trickle charge of the 1.8 watt I am told would take several days; this is less acceptable, but on the idea of redundancy it would be helpful.

Note: I am not proposing this as finished copy so to speak, but as the thread title notes, a step along the "still seeking" path. My particular interest is stuff that would be useful in poor neighborhoods in particular.

-- robert waldrop (rmwj@soonernet.com), August 07, 1999.


Robert, I think the C. Crane Company is a litle optimistic about their 10 watt panel's battery charging ability. Even assuming 100% efficiency, and 8 hour of full sunlight, you would only put back a little less that 7 amps in the battery (8 hours X 10 watts = 80 watts / 12 = 6.66 amps).

Looks like it would take about a week or so to charge a battery that was about half discharged.

I, too, believe in redundancy. I have a diesel genset (1650 gal fuel), many candles, Coleman lanterns, and oil lamps. I also have a bank of 12 volt deep-cycle batteries for the genset to charge to use with a 1000 watt inverter. Don't know what I'll use it for yet, but I have it.

Gerald

-- Gerald R. Cox (grcox@internetwork.net), August 07, 1999.


Robert, How about battery lanterns? Everything we have is battry and we've bought a lot of batteries.

-- Mara Wayne (MaraWAyne@aol.com), August 07, 1999.

The conversion from DC to AC is not too efficient (depends on the inverter, but it will never be 100% efficient). So If possible you should get 12VDC lights, radios or whatever. Flourescent lights are usually more efficient than incandescent bulbs. Car stereos often use more power than the kinfd of radios that use either batteries or 12V.

The output of most solar panels depends on how it is lined up with the sun, so to get the most out of it you need a way to adjust its mounting angle and you need to adjust it several times a day.

10 watts at 12 V = 0.833A. This may be enough to run a light and a radio. If not, you just have to let the battery charge for longer than the time you use the appliances for. Say you get 8 hours of sun, and you use an appliance for 2 hours a night. Then you could use an appliance that uses up to 40 watts (which at 12V is 3.33 Amps), without discharging the battery. Thats one of the advantages of batteries, they can change low power for a long time into higher power for a shorter time. If you do discharge the battery, then yes, it will take several days to recharge. Regular AC powered battery chargers are about amp, and can recharge a battery in a day or two, so your solar panels will take about a week (assuming lots of sunshine).

Robert, your equation, "8 hours X 10 watts = 80 watts / 12 = 6.66 amp" is not quite right. Watts are a unit of power(energy/time), Amps are a measure of current.

Power (in watts) divided by voltage (in volts) equals current (in amps), that part is right. But 10 watts is 10 watts no matter how much time passes. Power times time is energy, thats why the electric company bills you by the kilowatthour.

10 Watts / 12 Volts = 0.883 Amps. 0.883 Amps x 8 hours = 6.67 Amp-hours

watts x time = energy = voltage x amperage x time

.

-- biker (y2kbiker@worldnet.att.net), August 07, 1999.



I appreciate the good and useful information posted thus far in this thread.

I need to know a little more about DC systems to really visualize it, e.g. with the inverter system, you plug in the inverter, hook the extension cord to it, then plug in the power strip, voila. That's understandable to me at this point.

A DC system (as I have learned thus far) goes: battery to fuse to application via wire (a different thickness of wire for the DC current). I've read that the size of the wire relates to the distance the current is to be transmitted.

Then there's the issue of DC fixtures. I have a bunch of 50 watt 12 volt halogen bulbs (but it doesn't say "!2 volt DC", so they might be 12 volt AC). All I kind find are 12 volt AC fixtures. So I think I probably need to replace the wire in the AC fixture with DC wire. But I'm not sure.

I'm also unsure about the practical details of hooking the battery and wires and a fuse box (another big question I have, especially since ideally I would like to use some kind of an auto component), and then more wire to the fixture. I've noticed that DC flourescents and their fixtures are a bit on the expensive side. I have thought about using backup and brake lights.

So anything that can be said about these kinds of practical details would help me visualize this enough to write about it and put it together myself.

Thanks to everybody who's been offering information to "me the math-challenged."

Robert

-- robert waldrop (rmwj@soonernet.com), August 07, 1999.


That was supposed to be:

Regular AC powered battery chargers are about 4 amps, and can recharge a battery in a day or two, so your solar panels will take about a week (assuming lots of sunshine).

-- biker (y2kbiker@worldnet.att.net), August 08, 1999.


The more current, or the longer the wire, the larger the diameter of the conductor (metal part of the wire) you need. If the wire is too small, you will lose energy in it. This energy shows up as heat, so if the wire is really too small, it will get hot and could melt the insulation, causing a short circuit or even a fire.

The conductor diameter is described as the gage (or guage) of the wire. The smaller the number, the bigger the wire. I was just looking for a chart that shows what gage to use for what current but I couldn't find it. I'll post one if I find it.

But basicly, for 12V DC, if you use a wire larger than the wires used in your car you will be ok. Test it and if it gets warm it is too small. I often use 12 or 10 gage wire on my motorcycles even though it is overkill, because bigger wires are mechanically stronger.

Auto tail light or turn signal sockets are great, because the bulbs are cheap now, and if TSHTF you will be able to get them free from abandoned cars. Same with auto fuse blocks, plus they provide a handy place to keep extra fuses where you won't lose them.

-- biker (y2kbiker@worldnet.att.net), August 08, 1999.


Also, auto bulbs and sockets are sturdier than, say, flashlight bulbs because they are meant to resist vibration. If you use the kind with two filaments in one bulb (i.e. where the brake light and taillight are the same bulb) you can make a light with three brightness settings depending on how many of the filaments are on . It solves the problem of choosing wire gages too, just use thicker wire than the original wire attached to the socket (as long as you use the same wattage bulb as the original)

If the socket is plastic, it will have a ground wire which goes back to the ground terminal on the battery. If it is metal, the socket itself may be the ground, so you may have to attach a ground wire to it. (Normally the car body would serve as this ground).

You must use fuses or circuit breakers between the battery and anything else, and between the solar panel and anything else. Try to use ones that are rated for just a little more current than you expect to use, or a little more than the solar panel can produce. Remember that for a short time when they are turned on, motors draw more current than they are rated for, so you may need what are called "slow-blow" fuses. Have spare fuses.

If you don't want to worry about replacing fuses, there are DC circuit breakers which are self-contained (i.e. they don't need to be mounted in a breaker box like your home circuit breakers).

-- biker (y2kbiker@worldnet.att.net), August 08, 1999.


biker,

Thanks, you've given me some good things to think about. (Electricity is still black magic as for as I'm concerned.) About the auto bulbs, great idea. I was in Sam's buying auto bateries for my 12 volt emergency system a year ago, when it occured to me - no power=no gasoline. There will be thousands of cars everywhere with no fuel, and every one of them has a batery. Also, 12 volt lights, fan, pump (windowshield washer) and fuse box with fuses and wiring. If it comes to that, I think we will see the damnest things fabricated out of who knows what.

Also, why has no one mentioned wind generators? That was one of my first preps; cheaper and more efficient than solar. Of course you've got to have wind, but as some of you already know, I DO! :

-- Lon Frank (lgal@exp.net), August 08, 1999.



Lon:

Tell us more about your wind generator. I remember plans from the old mother Earth News about making a wind generator from an auto alternator. The idea would be to have several of them going, charging batteries. Being in Oklahoma, where there is lots of wind, that intrigues me.

Y2k biker:

Thanks for your continuing contribution of your expertise. Let me recap a bit what's been talked about:

1. A DC system looks like this as a "circuit": charging source --> fuse or breaker --> battery --> fuse or breaker --> application (which also has to be grounded)

2. Auto brake and backup lights are a good lighting option ("plug and play"). That is, they are their own fixture (although I assume they could be bunched and put into a fixture as long as there was physical room for the bulbs and their bases).

3. Use 10 or 12 guage wire (wire bigger than the wires in the car).

4. Fuses/breakers should be a little larger than the expected load on the wire.

At this point, I'm stuck on visualizing the fuse situation (looking for a "plug and play" easy/cheap to find option).

The use of an auto fuse box was mentioned, as were circuit breakers. Are DC circuit breakers expensive? Available at electronics stores? Electricity section of home repair stores?

-- robert waldrop (rmwj@soonernet.com), August 08, 1999.


Robert,

I'm embaressed to admit that my wind generator is still in the box, stored in the barn. (Very uncharacteristic of me; usually I would have played with it untill i understood it, but I guess I'm still hoping it will stay in the box.)

As I remember, it was a 30 amp unit, and needed 30 mph wind to reach peak performance. I bought it from, I believe, Arizona Wind and Power, whom I found on the web. About $600.00, I think. If all this sounds wrong, I'll go get it out, and perhaps give beter info. Man, I MUST be getting old (see "OT-Half Century" on the classic forum, posted today)

I bought the wind gen primarily because of price, and since I live on the Gulf Coast, it may serve me well, if need be. But then again, as I post this, the heat index is 110, and not a leaf moving.

-- Lon Frank (lgal@exp.net), August 08, 1999.


So here's the latest iteration, taking into consideration what we've talked about here, plus some discussion with other y2k helpers elsewhere.

Got juice? The essentials of a cheap power system include:

1. A way to charge a battery. This can be the alternator from a car, a portable generator, or a solar panel. With solar panels, you need at least 5 watts (about $70, provides about 13 amp hours a week), 10 watt panels cost about $100, and 32 watts typically cost $350+. These panels often have an adaptor so they simply plug into the car's cigarette lighter.

2. Batteries. You can use a car battery, marine or golf cart batteries are better. Repeatedly charging and depleting a battery eventually causes it to fail, the marine/golf cart batteries (known as "deep cycle") are designed for this kind of use & thus last longer. If you don't discharge a battery more than 20%, you can prolong its life considerably.

3. Inverter. This changes the battery's 12 volt DC power into AC power such as you get from the electric company. A 140 watt inverter costs less than $40, plugs into your car's cigarette lighter, and is widely available (electronics stores or catalogs). The inverter automatically shuts off when the battery power drops & you can restart the car if necessary to recharge it (with a car battery, after maybe 5 hours of a load equivalent to a 50 watt bulb).

4. Distribution. Use a good quality extension cord and a power strip. The extension cord connects the inverter plugged into your car battery with the power strip inside the house (keep this dry!). CAUTION: you must live within your energy budget. A 140 watt inverter will supply enough power for a 60 or 100 watt bulb, but not both of them, it would power a radio, CD player, or a small TV (black & white is best for this). Flourescent lights provide more light for less power, and larger inverters are available (more batteries helps too), but any way you look at it, the amount you can take out is limited by your "generating capacity" (which is limited by the fuel, equipment, or solar panels you have). "Your mileage may vary."

Got more energy ideas? Look for cheap candles at dollar stores & churches, buy lots of the tall ones in glasses (they last 3 to 6 days burning continuously and produce light as well as heat, don't leave them burning unattended or while you sleep). Flashlights and battery-powered lanterns are useful; for less money than you spend on batteries in a few months, you can get an inexpensive $20 solar small battery charger and some nicad rechargeable batteries ($2 - $6 each, depending on the size).

If you can't get an inverter, you can run emergency lights from a car battery. Use the brake and back-up lights, and some of the auto's wiring (DON'T use AC wire, such as in a lamp or an extension cord, with a DC battery power system.). To protect your system from fires or damage to your equipment, you need fuses or DC circuit breakers between the charging system and the battery, and between the battery and the lights or appliances you are using. The system must be grounded. A step down voltage converter (plugs into the cigarette lighter) can be used to run a small "C" & "D" powered CD player/radio from a car battery. For all alternative power applications, an inexpensive volt meter will be very useful. Don't hesitate to ask around for help or to research this subject at your library, this flyer gives only a bare minimum of information, use it as a survey of what's possible.

-- robert waldrop (rmwj@soonernet.com), August 09, 1999.


There's no such thing as AC or DC wire. You could use the cord from an old AC appliance as long as its not too thin.

I'm not sure where they sell the DC circuit breakers. I've seen them in some industrial electronics catalog. Maybe a boat or RV accessory shop would have them.

Y'know, I haven't said anything here about battery care...

Lead-acid batteries (i.e. auto or marine batteries) give off hydrogen gas when they are charging. This is not toxic but it is flammable so make sure you have some ventilation and don't charge them near any source of sparks or flame. And don't smoke near a battery.

This is why you have to occasionally add a water to the type of batteries that have removable caps on top, it replaces the hydrogen and oxygen that are released. The newer sealed batteries also give off gas thru a small vent, but supposedly contain enough water that you don't have to add any. I'm not sure but this might mean they don't last as long as the unsealed ones.

Anyway, use distilled water if possible, and add enough to keep the fluid above the top edge of the plates. Some batteries have a mark to show the ideal level. If the top of the battery is dirty wipe it off first so the dirt doesn't fall inside.

A little acid mist may also come out of the caps and vent so put something under the battery if you want to protect your table or floor. A car floormat would work nicely. If you get any acid on your hands or clothes wash them immediately. Couldn't hurt to wear eye protection when working with a battery although most people don't.

-- biker (y2kbiker@worldnet.att.net), August 10, 1999.


If you have extra batteries, keep them charged, or rotate them. You can buy batteries dry, with the electrolyte in a separate bottle. They will keep forever this way.

-- biker (y2kbiker@worldnet.att.net), August 10, 1999.


Thanks for everybody's excellent tips and comments.

In a private email, a helper suggested looking into batteries used in big diesel trucks. Today at Sams I noticed they had "GNB super crank" 8D 12 volt batteries, 1300 cranking amps, 450 reserve capacity, for $99. any thoughts about this (as compared with 6 volt trojan golf cart batteries)?

-- robert waldrop (rmwj@soonernet.com), August 14, 1999.


Much depends on the climate your in of course. Duh Michael. But if you have lotsa sun consider looking into solar steam power generation, lotsa wind - wind turbine, lotsa rain - well... I'm designing a water turbine to be used within the storm drain system. Similar to a wind turbine (not vane,mill) but because of the pressures and vacillating flow, I am having to be a bit more creative. If I work the bugs out, I'll get back to you on it.

-- Michael (mikeymac@uswest.net), August 15, 1999.

Great thread. How many of you have or know someone that has a lawn edger? That little 2.5hp to 5hp gasoline engine, can, with a little modification power a quite large capacity automotive alternator. Many auto alternators now have the regulator built in. At high idle, 1200-1800rpm, these engines will run approximately 2.5 hours per gallon of unleaded (87 octane) fuel. Now 2.5 hours @ 45amps output of the alternator will easily boost, backup for cloudy days etc, most of these systems. The modifications include a 5" to 5.5" pulley mounted on the engine and use the pulley that is installed on the alternator.

This "portable" genset will have barterable output. I will trade charge time for fuel in my neighborhood. I have allready built one on a rotary mower but I don't think the deck will last long and it was hard to flame cut the holes for mounting the alternator.

Another system I have now is 6-6v bicycle generators mounted on 1 mountain bike frame using a balloon type tire ( not knobby ). I have 3 in parallel going to my 6v deep cycle batteries X 2. If you fill the rear tire with water it makes a great flywheel and even my grandkids think it is great to pedal a real bike.

I "packrat" old thrown out APC's (computer backup power supplies), open them up, disconnect the tired batteries in them and atatch them to my batteries. A 250w APC can power my 14cu. ft. chest freezer, through a cooling cycle, with a 1 hour pedal charge. Total cost was for the batteries @ $60.00 each retail. You can pickup used deep cycle batteries for about $3.00 to $6.00 ( make sure they are tested for no dead cells when you purchase them ). There is a recipe' for epsom salts and water (available on the net) that I use to re-energize the batteries. It cleans the deposits off the cells.

I hope this keeps this thread going. I really enjoy it. Thanks byker

-- Richard Bloom (rfbloom@uswest.net), August 18, 1999.


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