Survive Infinite Dangers: The Family Survival Guide of 21st Century Dangers (25 page)

It’s the beginning of your system but the entire system is not just one, or more, solar panels. Solar panels are mounted in rugged frames just like picture frames but much sturdier. Treat them as sheets of glass and you will never have an expensive accident. An array of solar panels sliding off a roof all at once onto a concrete driveway will earn the video a spot on a TV reality show (one did!). What an expensive mess! The carpenter’s rule of “measure twice and cut once” comes to mind. After a severe disaster with “bad guys” roving about a few solar cells propped up in the driveway and pointed south is like putting up a sign saying “a survivalist person lives here – this place is probably loaded with stuff worth killing for”. Hmm, and they probably would.

If you want to take the chance that a disaster will not be EMP build your system then permanently mount the panels on the south facing side of your roof. If you want to spend the money go for the moving panel poles and mounts where each panel follows the sun automatically moving during the day so that each panel is always pointed at the sun. The extra sunlight it picks up is more than enough to power the motors that move each panel with plenty of extra electricity left over. But they aren’t cheap. They are among the many items BWS sells. Like everything solar or wind power or the many other ways to generate power (geothermal, water, and dozens of other ways – anything that moves or is a different temperature than its surrounding can generate electricity). You’ll have to decide just how long you’re willing to wait to have something “pay for itself”. That front-end investment can make you wince even knowing you’ll cross the break-even point in just a year or two. Factoring in the “cost of money” (what the money spent would earn if invested) anything past seven years should be considered carefully. You may have to buy that particular item to make other items work or you may just want to so as to be truly “off the grid” in every possible way.

Solar panels are actually a grid of semiconductors. Oops. What about EMP? The true answer is, I have no idea. That would be a question for BWS. Perhaps simply shorting the output is enough to protect them or maybe cover them with multiple sheets of aluminum foil or something like a drop down pure copper cover that shields the solar panel from EMP. Or, considering the size, it may not be possible to protect them short of burying them in a lead box six feet underground. Anyway, if nothing else this is an extra reason to have plenty of batteries 100% charged all of the time.

The electricity coming from the solar panels (a “panel” being hundreds to thousands of interconnected solar cells) is direct current meaning they are just like a battery as opposed to alternating current like what comes out of a wall socket in your home. Since it is DC as opposed to AC, resistance in the wire that carries the electricity from the solar panels is a major factor and everything possible must be done to minimize that resistance (which maximizes the voltage and amount of current (amperage) the panels will be able to deliver to your storage batteries. Use only pure copper wire, the larger diameter the better and the shorter path to the battery bank the better. This means minimizing the resistance (measured in Ohms) the voltage and current (voltage in volts times current measured in amperes equals power measured in watts).

That’s why the electric power system of the world runs on alternating current as the technology of AC power minimizes wattage loss in the wires that carry the electricity. Unfortunately, a solar cell that generates AC has yet to be invented. While we wait for this invention, our goal is to minimize the power lost before it reaches the battery bank. Your battery bank will be lead acid (think of a car or boat battery) and they need to be vented. Thus a system such as in the attic right below the solar panels (on the inside of the roof) is optimum for a short “run” but must be carefully planned for safety. A walk-in room in the attic that receives some cooling as well as ventilation (while remaining dry) is something to consider. Once the batteries are powering the inverters (an inverter converts DC into AC) you’ve accomplished the most difficult part. Although inverters can get hot (especially under load) and one that starts a fire after exploding is a very poorly designed system. Everything must be fused (either fuses or circuit breakers – fuses must be replaced while a circuit breaker can simply be reset). A quality inverter includes a circuit breaker as well as a temperature sensor that shuts it down if the inverter overheats. Working with electric power is not something you want to cut corners on. BWS has block diagrams of various systems in their catalog and shown in recommended books. Basically the DC voltage from the solar panels run through a sensing and control system to avoid putting too much voltage into the batteries. An overcharged battery can be dangerous! I am not an expert on solar power systems (the folks at BWS are!) but I’m not aware of using any other type of battery than lead acid for voltage storage. There are various types but I’ll stick to two types. The first is the plain old car battery lead acid type. They tolerate heat well and are relatively inexpensive. The other battery is also lead acid but “deep discharge” marine batteries (called marine because they are mostly used in boats). They are more expensive than what you find in vehicles. What’s the difference? The deep discharge is preferred for a solar system (or any alternative power system such as wind or water) as it can tolerate being discharged to almost zero then recharged many more times than a “car battery”. Some batteries have “memories” remembering what voltages they’ve put out in the past.

Run a car battery down to a few volts more than a few times and it will begin to discharge on its own after awhile. A deep discharge marine battery can tolerate many more discharges down to a few volts then charged back to full voltage. Both batteries are roughly the same size for the possible amount of full charge. Such batteries are usually rated in “amp-hours”, how many hours a battery is capable of putting out a certain amount of current measured in amperes. The voltage goes down but the amperage stays the same (for measurement comparison purposes). Everyone building/using a battery system as described has a preference of “car battery” or “marine battery”. I prefer car batteries as they are easier to find and cheaper. A professional (such as BWS) would probably grimace at what I just wrote. But I’d rather include something to shut the system down (manually or with a sensor) when the voltage drops to, say, eight volts. Some inverters go into melt-down mode if subjected to a voltage below a certain level which is fine for an inverter you keep in your car but not good in a system like we’re talking about where the voltage might drop quite a bit by, say, 5 AM with the batteries and inverters powering your electric blankets all night. It should go without saying if you have no sun the solar panels generate no electricity. That’s where the batteries come in. They store electricity to power the inverters at night, on cloudy days and when a peak wattage output is needed more than the solar panels can provide even on a sunny day.

The inverters simply change DC into AC. Usually 120 VAC 60 Hertz, the same as comes from your wall socket (in the United States – 220 VAC 50 Hertz in many other countries). A control system almost always has volt meters to measure the DC voltage from the solar panels and from the batteries and a meter to measure the AC voltage from the inverters. More sophisticated systems measure the Hertz (cycles per second) and one more step is with an oscilloscope to view the purity of the AC waveform. The goal is 120 volts AC 60 Hertz of pure sine wave. Some cheap inverters put out more of a square wave than a sine wave plus the Hertz varies all over. If you want a cheap means to measure the frequency (Hertz) plug in an AC powered clock with a second hand. Clocks are timed by the frequency of the AC power running into it. If one revolution of the second hand takes 60 seconds then you are holding at 60 Hertz. Vary the formula up and down from there. There’s no easy way to view the quality of the wave form other than with an oscilloscope. Many complete systems are shown in the BWS catalog and other material they publish so I won’t waste space in this book they already have published plus appears on their Web site.

In a nutshell, make your system permanent and run it often even if it only runs some light bulbs. Turning a system on after a year only to discover the batteries have discharged on their own (that does happen) or something else is wrong is discouraging especially when you need it the most. For a real test plug in an inexpensive television (inexpensive in case it damages it) and see what the picture looks like and how it sounds. The recent change to digital television makes this test a bit more difficult but still worth doing. If you get a good picture and good sound (no hum) you have a good system.

That pretty much completes your own home owned power and light company! After your initial expenses the power you generate is very close to free. A nice novelty when you have power, a potential life saver if a disaster has occurred and it may be many months before the lights come back on.

One last comment is to remember all the words of the Stealth Chapter. Even a sliver of light from your safe area can be seen for a long way when only the stars can be seen at night in a city with no electric power.

The types of batteries best for various applications will be obvious but I’ll list the most common batteries here so you can identify the best use of batteries you encounter either as a new additions to your inventory or batteries you already have. This is for information only:

Lead-acid batteries: already discussed in depth. Advantages: put out major amp/hours especially for the money. Disadvantage: definitely not pocket sized!

Nickel-Cadmium (Ni-Cad): Rechargeable many, many times. Until the last few years Ni-Cad was the most common batteries used in portable radios such as walkie-talkies. They discharge on their own about 1% a day which is a real disadvantage and causing them to fall into disfavor. They also have a “memory” tending to drop to low voltages if you forgot to charge these batteries. They are cheap but no longer a good choice.

Nickel-Metal Hydride (Ni-Mh): Becoming the new favorite although they also lose about 1% of their voltage per day. They offer a huge amount of amp hours (a/h) over other small batteries. Usually found in walkie-talkies they are often placed in a charger holder every night thus the 1% loss per day is not a problem. But don’t let one sit for a year without charging it. And they may be recharged 400 plus times which makes them batteries capable of powering five watt walkie-talkies for years.

Lithium-Ion (Li-On): They are gaining ground on Ni-Mh batteries as they have even greater amp/hours for their size and recharge in about a third the time of Ni-Mh. They also discharge much slower on their own. They are the best choice for reliability and every specification except for price. Expect to pay a lot more for Li-On batteries. But if you’ve spent hundreds of dollars for good walkie-talkies why spoil it with less than the best batteries? Because of the high price but great long-term operation always keep your eyes open for low-priced (new) Li-On batteries. Most people don’t know the differences among batteries so they buy Ni-Cad based on price and pass up Li-On even though the Li-On provides years of service. Thus, some sellers are forced to sell Li-On at low markups. Take advantage of that!

Non-rechargeable alkaline: Cheap and cheap. They put out 1.5 to 1.6 volts DC versus 1.2 volts DC for the other three portable batteries. They hold their charge for two to ten years. They are often so cheap they are always worth having packs of them around. I bought some for 10 cents each yesterday. You can’t beat that! You’ll also find some electronic products (especially cameras) need 1.5 volts to operate correctly or go downhill not much below 1.2 volts requiring constant recharging. I can’t pass up a display of “48 AA batteries $6” so I have hundreds of extra batteries. Refer to the supplies chapter and the list of items you can’t have to many or too much of. Batteries are on that list! If you end up with too many I will guarantee you they will barter at ten times the price you paid for them when people need batteries but the stores that sell batteries have all been looted then burnt down.

Chapter 21

Supplies, Equipment and Tools

Items You Can’t Have Too Many or Too Much Of

*for items with asterisks refer to notes below