Having owned a small solar system for a year now, I have a few things to say with a tribulation outlook.
Some people like to have a sense of security for future emergencies, not minding large expenditures in return for peace of mind, but if you would feel sore to have made large purchases for tribulation purposes, if the trib did not arrive in your lifetime, then you should be as wise as possible when it comes to purchasing solar power for tribulation use. If even the Apostles were on earth today, I don't think they could give you an answer to the timing of the 70th Week. It's 2010 as I write, with changes made in mid-2012.
Perhaps you should not purchase your solar panels just yet, as there is a new thin-film type (using cadmium telluride instead of silicon) promising to cost as little as one dollar per watt; i.e. a surface area providing 100 watts at peak sun times should soon cost only $100. I don't like to put words in God's mouth, but what if He is indirectly providing these cheaper types for tribulation use? Shouldn't it mean that it's okay to put off purchasing until they're available everywhere at low prices? Wikipedia has an article on thin films:
I was "fortunate" when the electric company wanted about $12,000 to install power to my new property. It made easier to go solar; I took the plunge with an estimated $12,000 cost that includes eight 130-watt solar panels and eight 530-amp batteries (included two propane appliances), which is considered a small solar system...but it's enough for me alone. The solar alone, apart from a propane fridge, water heater, and clothes dryer, came with a cost of about $8,000 US. I installed it myself, electrical panels and all. If you install your own, have a solar-power professional come in to check your work when done. I didn't, but then I know something about electrical installations, and besides, the expert I eventually called never showed up (understandable because I took his work from him). The electrical installation is, like most other things, not terribly difficult, once you've done it and know how. The first time can be a trying task, however, as it was for me. But one cautious step at a time, it got done, and it saved good money. And so far, the system has not exploded, or made strange sounds.
My 130-watt Kyocera panels (not thin film) were far more expensive in 2008 than in 2012; at the page below, panels up to 240 watts are listed at $360.00 and less, as of September, 2012. The threat of thin film may have pushed the cost of these panels way down. The webpage below tells (and shows in a chart) that, after testing, thin film out-performed, in the efficiency category (though the definition of "efficiency" is not well explained) the common / conventional types of panels. This contradicts what others are saying (perhaps a rumor to keep thin-film sales down).
While thin-film panels should be cheap enough soon to make costs a virtual non-concern, batteries are still fairly expensive (mine were about $250US each, but they may have gone up). The good news is, we shouldn't need many batteries, and the present world-emphasis on battery improvements may bring their costs down just in time for your needs. The battery charger (mine $400), and the inverter (mine $1,600) to convert the solar power to AC, are also significant in cost. After these expenditures, you'll be off to races...as the turtle.
One thing that I've learned: it would be a good idea for all tribbers to have at least four panels and four batteries. You can run power tools when you need them, often enough for building shelters if there are not too many workers at the same time. Washing clothes in a washer, no problem. Some light-bulb operation at night. Want music? No problem. Need to use the computer (laptops use far less power than desk tops)? No problem. The four panels will do it in most times of the year in most places without worry, and I've learned that I can even run a small (5.5 cubic foot) freezer and a small fridge using just four batteries and eight panels. All eight are not always needed, but in cloudy periods, the extra four can be the difference between frozen and thawed freezer foods.
A water pump takes very little power for your household needs if it's pumping horizontally, say from your rain barrels or nearby stream to a pressure tank in the house. Pumping vertical is another matter. The depth of water in a well determines how much wattage is needed to bring it up. Your pump's tag will inform you on the approximate amps/wattage used. I have a small submersible pump (1/6 HP) that, according to a typical watt meter, uses about 230 watts when pumping horizontally 20 feet and vertically three feet in a 1.25" pipe. I don't know whether it's correct to say that a 1/3 HP motor would use twice that wattage, but it sounds about right. If you can arrange an alternative water supply for baths, toilets, and washing, the amount of time pumping household water can be minimized so that the power needed even for a deep-well pump should be slight (i.e. easily handled by the four solar panels and batteries along with your other electrical needs).
Your alternative water supply can be from your deep well if you provide a large tank (or several small ones) in or just outside the home. That is, fill it on sunny days when the solar power is more than you need for other concerns. Then use your small pump to bring the water horizontally from the large tank into your home's water system. Filling a large tank would be an especially good idea for the dry season in your area, and you can even water the garden with it. BUT CAUTION: deep wells may have little replenishment water so that trying to take too much water out at any one time, as when filling a large tank, can dry out the well and burn the water pump, a fierce let-down in the middle of the tribulation. You've got to know your well's replenishment rate, and take from the well pipe only so much at any one time, then turn off the pump, then let the well pipe fill up again. (Are there not pumps that shut off automatically when they run dry?)
The obvious threat of watering the garden (i.e. using lots of water) in a trib situation is that the pump may fail due to excessive use. Having an extra pump or even two may be a good idea if you value your garden enough. In 2012, my area that usually has plenty of summer rain had a near-2-month drought. It can happen to you..on the year that your pump fails.
I'm reading online that a 1 HP deep-well pump uses 8 to 10 amps, or about 1000 - 1200 watts. While you may not use it very much on a daily basis, even so, regardless of how little power it uses daily, there is the potential problem of deep battery drain when 1200 watts are in-use. The situation is even worse when the pump and other appliances are being used simultaneously. I haven't yet checked with anyone as to whether sudden deep drains of batteries, on a regular basis, is harmful, but when my 700-watt jet-pump runs for even five minutes, the battery voltage goes way down temporarily (i.e. it comes back up when the pump shuts off). It made me nervous, especially after someone at Outback's blogs warned that battery cells can be ruined permanently with sudden drains. I stopped using my well water and pump, anyway, no sooner than it was installed, just in case. I do fine without well water because I live alone, but sooner or later I'll need to deal with the problem.
The regular deep drains while using 700 watts may not have been at all problematic had I been drawing from all eight batteries. However, I use only four for AC needs, while working the other four separately for computer and light-bulb use only, with straight DC power. I use the toaster (1000 watts) almost daily, but it runs for only a couple of minutes. No problem for the four batteries, especially when it's sunny out. And that's the point. If you can arrange your deep-well pump to work only when it's sunny, then your power is coming directly from the panels = sun, thus reducing what the batteries need to contribute at that time. If you have sufficient panels to get 1200 watts on a typical sunny day, you will not have battery concerns at all...if the pump is run when it's sunny. But deep-well pumps are set to work automatically; if someone forgets to shut off the water hose or kitchen tap (not likely, but this example makes the point), then you could have a potential battery disaster when dusk or clouds arrive.
It may perhaps be good advice to get a pump low enough in wattage that it can run on your four or eight panels alone, rather than getting more panels to power a higher-wattage pump. But the pump wattage must at least be sufficient to lift the water in your particular well. The the depth of your well pump (not the total depth of the well) will determine how much power is needed to lift. After using the power needed to lift the water, the volume of water received per unit time will depend on how much extra wattage the pump can achieve after maintaining lift. That is, a lower-wattage pump gives less volume per unit time, which may be a good thing if your well has a low replenishment rate. But, as is the case in most households, the pump has to do more than lift; it must also fill the pressured water tank in the home, typically set at 40 psi.
As the tank is filling, pressure inside it goes up, and water-volume entry per unit time is reduced, which is why my jet-pump runs about 5 minutes (I didn't time it) to fill a small six-gallon tank. It shocked me to learn this. A six-gallon tank not under pressure would fill in less than a half minute, greatly reducing both the electrical usage and the wattage required to get water into the home. This is one good reason for you to consider the expense and unsightliness of a large water tank on a tower about 20-40 feet high. Forty feet is required to get decent tap pressure, but water will still run if the tank is only 20 feet above the tap, though you may need to learn patience at the tap, as well as place the shower head directly above the head rather than on the wall.
You can have your pressurized tank and eat your cake too by having an open tank as well for when it's needed. I use very little water daily as I take 2-gallon "showers" (because I haven't used running water in more than four years, and I'm still quite normal). It's really no burden whatsoever, when you get into the habit, to get yourself a bucket of water from an open tank, when you need to wash. The great thing about tank water, praise God, is that all debris either sinks or floats, and the water in between becomes clear no matter how muddy it is to begin with. Skim off the floating matter, and you'll have fine water for bathing. You can appreciate a shovel and nature's fresh air, to reduce toilet water to zero, and you won't stink up the bathroom neither.
I know nothing about operating a solar-panel system apart from utilizing a battery pack, but I assume that it can be done for household use. If so, then, without batteries, one can only have power as the sun shines. The 130-watt panels can only bring in 130 watts each when the sun's angle is straight on, when the sun's position is at "high noon," and when the panels are new (they produce less with age, though they age slowly, to a death at about 20-25). The further north one's location, the less the panels can get sun from a "high noon" (directly overhead) position, albeit a position of one or even two o'clock (achieved in summers in the north) is nearly equivalent to a noon position so far as panel power goes.
Still, each 130-watt panel can only run two 60 watt bulbs, for example, at peak sun conditions. It's so precious little it makes you want to cry, especially as the sun is often on a significant morning/evening angle. When using all four panels (= 520 watts max) and no batteries, your pump is not going to lift water, at most times of even sunny days in summer, if it needs 520 watts to lift water. Do you want to run water into an open tank, on average, an hour or more daily? Then arrange the potential panel power to equal the pump's needs from, say, the 9 o'clock position to the 3 o'clock position, giving you six hours daily of pumping opportunity (you're not going to get six hours daily of pure beautiful sunshine. About the only good thing about owing a solar-power system is that you appreciate blue skies more than ever. But you grow to dislike overcast days more than ever. For every enjoyable sled slide down the snowy hill, one must first climb the hill.
In winter, your location may as far north as where the sun achieves merely the 9 o'clock position even at noontime. In Canada, the sun on December 21 is even lower than 9 'o'clock at noontime. Your pump needing 500 watts may not lift water at those times of the year unless there is battery power to resort to. If you are going to forego the batteries due to lack of money, you'll need to spend more for panels, which may be great when their prices come down. If your water supply in winter is minimal, you have the option of filling small containers in summer for winter storage. If the containers can handle the swell of freezing water, you won't get wet floors when you bring the container into the house to thaw. And you can use the containers the next year too. You get it: don't use rigid containers that crack with freezing water.
Alas, you'll probably decide to use batteries so that you don't have the headache (or potential threat) of timing every electrical use for when the sun shines. Go for it, get the batteries, even if you need to beg for the money, or deliver pizza in the evenings for a few weeks.
At the US-Canada border (not including the cloudy west coast), they say that solar panels achieve, on an average basis over a 24-hour period in the winter, the equivalent of one to two hours of sun directly overhead. Using panels capable of providing 520 watts max at high noon, it means that you'll get an average of 520-1040 watts daily for use. If your water pump needs 500 watts to lift 300 gallons per hour, you'll get a maximum of 600 gallons daily, on average...providing you don't use any other electricity apart from the water pump. And that's the kicker; if you run a fridge(s) and freezer(s), you may be short of power in winter as it is, so that also using a water pump for significant water volume may become a nail-biting experience. Who needs 600 gallons daily? Ask the small commune. There will be small and large communes of Christians in the trib.
My four deep-cycle acid batteries are six volts each for a total of 24-25 volts of electric "pressure." (One can easily arrange four batteries to put out 12 volts.) All solar batteries are rated in amp-hours (the number of amps the full, new batteries can provide for one hour of usage; they put out less with age). Mine are rated at about 530 amp-hours (if the batteries are discharged over 100 hours of use), meaning the company promises that four of them will provide the equivalent of 530 amps x 24 volts = 12,700 watts over a period of one hour...or 1,200 watts for 10 hours, etc. However, as pointed out in the brackets above, the total amps received depends on the rate (per unit time) of discharge. If the entire battery-bank load is used up for pumping water at 1,000 watts steady, the four batteries could not provide 530 amps / 12,700 watts per load. If all I use all day and week long is a laptop running on 50 watts, a full bank of the four batteries will provide significantly more than 12,700 watts, or so the company promises.
In other words, the Surrette battery company claims that my four new batteries will provide 530amps / 100hrs = 5.3 amps (= about 130 watts) steady over 100 hours. Part of the good news in this regard is that small fridges and freezers run on about 135 watts and 80 watts respectively. But the point is to alert you to the bad math you'll do if you go by the battery's amp-hour rating when most if your electrical usages will tend to be significantly higher than a steady 130 watts. But another good point is that we can maximize total battery output by using one appliance at a time whenever possible / convenient (unless it's day / sunny out when battery power isn't being used).
If you decide to go solar, one of the first things the salesman will educate you about is that batteries are NOT to be discharged past their 50% point. It harms batteries when they are regularly discharged below 40-50% capacity. They say that once in a while is not meaningful, but just so you know, you'll need to re-charge four batteries like mine after about 4,500 to 6,000 watts of use from a full bank. But then the solar panels will usually be re-charging them as battery power is being used up. The battery capacity will go up and down constantly, and one of the pains (unless you're the solar-power monkey type) is to keep an eye on batteries almost daily (or even more than once daily at times) to assure they are not drained beyond 50%. If the battery bank tends to go down in power with each passing day, hope that it's due to low sun rather than insufficient panel potential. The time to get sufficient panels is before the skincode arrives.
When my batteries are down to 50%, it could take up to a dozen days to re-charge them fully when cloud cover is ample...if I had been using only four panels. You can readily see here the benefit of having eight panels instead of four. Long cloudy periods are what do battery damage, when batteries tend not to climb in power, but rather drag on in the 50% area, day after day of usage. In these times, it would be good to have a gas generator to bring the battery capacity up to about 75%. Charging with a generator beyond 75% battery capacity is much a waste of gas, as the charger's input into the batteries goes down with increasing battery voltage, yet the generator is still running regardless. If only we could coax the generator to provide power when it's not running.
Once the batteries have achieved about 80%, they are harder to fill with electrons because their higher voltage "fights back" against the charge seeking to pump electrons in. This is true even when charging with solar panels. In other words, charging from 50% to 75% (about 3,000 watt-hrs) is fast and easy in comparison to charging from 75% to 100% (another 3,000 watt-hrs), and for this reason 100% is rarely achieved. I have questions as to whether the 75% to 100% really does prove as much power as the 50% to 75%, as it seems I get more power in the lower rungs because it comes out more slowly.
In any case, it takes two to three hours of generator charging (with the system set at a maximum 1,400 watts intake, to grow my battery capacity from 50% to 75%. (I get to choose what the maximum input wattage will be, though it's partly determined by the strength of my generator...that I don't want to ran to the max because it reduces engine life). I purchased an inverter generator (Yamaha EF2400IS) that saves gas when it's putting out less power, whereas other generators (less money) tend to use roughly the same amount of gas regardless of how much power they push. This means I save gas when charging in the higher-end battery capacity, and when I choose to charge at 1,400 watts rather than 2,000. In the tribulation, saving gas this will be very meaningful. This Yamaha generator can be converted to run on propane, which I hope to do for tribulation endurance because propane has a long shelf life in comparison to gasoline. Hint hint.
I used to think that there's no use getting an electric fridge for the tribulation because the extra cost in panels and batteries would be better spent in canned / dried foods. But then i learned that fridges have become much more efficient, which allowed the risk of purchasing a small one (two-feet square, 55" high, 11 cubic feet), but without freezer. It probably has as much space as your large fridge due to not having a freezer. Its annual usage in normal household conditions is rated at 306,000 watt-hours (306 kwh), or an average of about 840 watt-hours daily. A watt meter (simply plugs into your wall outlet) showed that the fridge ran on 130 watts, suggesting that it runs 840/130 = 6.5 hours per day = 16 minutes per hour.
But I don't run it at night. It's a huge advantage. It's still cool in the morning. In fact, I've been able to use a small freezer too, and shut it off for 12 hours daily, exactly when the sun don't shine. Think of it.
Testing with the watt meter (every solar-power monkey must have one), which keeps track of total wattage used on an on-going basis, this 5.5 cubic freezer, rated for 193 kwh annually, used up only 23 kwh hours over 46 days from July 1st to August 15, in a house not air-conditioned. That translates to 500 watts exactly per day, or 186 kwh annually...but it will do much better in all other months because they will all be cooler months, and besides, the freezer is going outdoors (in the shade) soon to save wads of watts.
PLUS, the fridge doesn't need to be turned on constantly. If I turn it on for an hour in late-afternoon, it will still be cool by morning when the house is cool at say 60 F. Imagine how much better the situation would be with, say, four inches of foam insulation on the fridge walls. It brings to mind the idea of a walk-in cold room for trib purposes, so highly insulated that even a small motor can keep it cold.
I can run both units all day during sunny periods without losing any battery power, and even having spare panel power after that to charge batteries some. For many areas, the sunny periods are in the hottest ones. Perfect. If there are a string of sunny days, the batteries will approach 100% even with the two units running. It was like a miracle to fall upon this. I thought I was destined to live without a freezer for the rest of my life.
But, caution, the freezer manual tells that its thermostat setting should be at about 0 F (-18C), while that temperature will not be maintained by shutting the unit off for 12 hours nightly in a normal room. But I don't care. In cloudy periods, or when the batteries are low, I use the freezer's lowest setting, and foods stay rock hard. Only the slightest sign of humidity could be seen inside packages of beans after a 12-hour shut off, but things like beef could still be used as cannon balls. There is a bacteria said to grow in foods from temperatures of about 5-10 F, and though I cannot recall the name of it, it didn't seem be very common, and of course it has to be in the food before it's put into the freezer. But if we sufficiently cook what's in the freezer, any bacteria will be killed.
It was the seven amps (800 watts) on the old fridge's tag that caused me to think fridges and solar power were not compatible. When trying to figure how much power your own fridge will use for solar-power purposes, do not judge by the amp rating stamped on the unit's back side. For example, if it's rated at seven amps, it could use less in normal operation. The new freezer has 1.4 amps and 115 volts on its tag, amounting to 161 watts, and yet the watt meter shows that it starts up at 89 watts and eventually comes down to as much as 79 watts after running for a while. Get a watt meter ($25-40).
New fridges inform the customer (let's hope they are accurate) on expected annual wattage, making it fairly easy to approximate its running wattage per given situation. If the fridge uses 365,000 watts annually, it's 1,000 watts daily and 42 watts per hour. But fridges don't run constantly. If one runs for 20 minutes on the hour (i.e. 1/3 the time), it's operating on (42 / .33 =) 126 watts. It sounds unbelievably great, and it is. It's only as much as two 60-watt bulbs on for 8 hours of the day, and less if the unit is shut off for the night. Think of how much battery life is saved by shutting fridge and freezer off for the night. After a year of testing, I may get a second freezer, as I've finally started the garden. Much garden produce can be harvested as the minor freezes start occurring, when freezers outdoors (north side of the house makes sense) will use less energy.
Inexpensive thin-film panels should prove to be important for us. The film doesn't last as many years, nor capture as much energy per area, but for trib purposes, who cares? The main goals are: 1) using little battery power (because we don't want ruined batteries in the middle of the skincode period), and, 2) getting batteries recharged as quickly as possible, and as fully as possible. The more panel power, the better. However, until one has personal experience on a product, perhaps one shouldn't give thumbs-up so hastily. But we should look into thin-film once it's available at low-enough cost.
In winter, I can use the outdoors to cool the fridge, for I arranged the other side of the kitchen wall to be an unheated storage room between kitchen and garage. The wall behind the fridge can therefore be opened to let cold air to its back side, and thereby to the other sides, tops, and bottoms...but encasing the fridge in some way so as to keep the cold air from entering into the kitchen. In other words, if you haven't yet built your trib retreat, you can do the same if you think it will be helpful.
Also, for the handyman, here's an idea. With heat-exchanger tubes (often on the back of fridges) located in the cold, they will release heat more efficiently, requiring the fridge to operate less time. However, I haven't as yet checked to see whether the fridge's condenser pump or exchange system will be adversely affected in any way by being in the extreme cold. The potential problem is that the chemical in the tubes may not liquefy, and may therefore spoil the heat-exchange process. However, I tend to doubt that this would be a problem, but aim to ask the fridge people anyway. Below is a webpage with this general topic telling that cold temperatures may or may not kill a freezer's / fridge's compressor pump, but then the freezer can be turned off in the coldest periods (at the risk of forgetting to do so):
Both the webpage above and below say that extreme cold kills the freezer's insulation, making the unit require more power in warm months. Some say they have operated freezers in temperatures well below freezing without failures. Where do we find what is rumor verses what is true? Hopefully, your fridge company. Perhaps a good safeguard is to use your old freezer outdoors in winter only (bad insulation will then be less problematic), and to purchase a new one for indoors. If the pump goes in the outdoor one, it can still be used for some cooling purposes. If it holds water, use it as a tank...bonus with it's own lid to keep out the flies.
I've just called Danby to ask whether their freezers can go outdoors in extreme cold, and the fellow, who didn't know what sort of insulation the freezers come with, or how I could remove its heat-exchanger unit, quickly answered, no. When I asked what the threat might be, he said the condenser coils may freeze. He sounded like he really knew his stuff here, but then perhaps he is trained to give this information out because the next thing he said was that the freezer is longer under warranty when placed in a cold environment. Therefore, the freezer companies know that there is/are some ill effect(s) to freezers in extreme cold, and while they may be hit-and-miss threats, as this fellow suggested concerning the condenser coil, the companies don't want freezers in the cold because they loose money on those who may purchase extended warranties.
In any case, the man answered "yes" when I asked whether a 60-watt light bulb placed beside the condenser coil would keep it from freezing. Not that I would use a 60-watt bulb 24 hours, as that would be counter-productive to the very purpose of placing the freezer outdoors, but it's telling me that, where the outdoor temperature is yet warm enough to keep the motor running a significant amount of the time, the motor may itself keep the condenser coil from freezing (the motor on my freezer is warm / hot to the touch when running). It may also mean that a little insulation wrapped around the motor and coil in cold outdoor temperatures may be of great benefit to reduce the threat, though, safe to say, the insulation is practically of no value in eliminating the threat if the outdoor temperature is cold enough to keep the thermostat from turning on the motor.
He said that the condensor coil (not to be mistaken for the heat-exchange tubing) is beside the motor. He said without doubt that cold temperature does not adversely affect the operation of the heat-exchanger tubes.
What I'd like to do is disconnect the heat-exchanger tubes from the back of the fridge so that the back side can be insulated. It's counter-productive to release heat near the fridge...which is why I'd also like to re-locate the tubes further away. I don't see why one couldn't locate the tubes outdoors, or in an unheated crawl space under the house. It would require a few feet of extra tubing to be soldered on, but it may be do-able, and may well be worth the money spent to do it. My new freezer, and many newer units, have the heat-exchanger build inside the walls of the unit so that the tubes cannot be accessed. In my opinion, this is a lousy way to release heat, in a trapped space as close as possible to the cold box.
The storage room outside the kitchen will act as a walk-in freezer when it's cold enough, and a walk-in fridge when average temperatures are near freezing. That will give the fridge motor a break just when it's needed most, when the sun crosses lowest across the sky. But a walk-in "freezer" room such as this can thaw even in winter.
Solar systems (i.e. number of panels versus batteries, etc) are usually designed based on low sun-hour rates so that households will have enough power to get through winters with minimized generator back-up. But you don't need to follow this rule if you have other methods of keeping your foods cold, if you minimize your lighting (dimmer switches sound like a great idea), reduced oven cooking, hang clothes to dry, etc.
Four 130-watt panels receiving three sun hours daily is a total of just (130 x 4 x 3 / 24 =) 65 watts per hour for 24 hours, i.e. 65 watts constant on average all year long (this is the math you'll be doing with your particular situation). To recharge four batteries like mine when they're 50 percent discharged would then require about (6,000 watts / 65 =) 92 hours, or about four days...on average, and that's if you use no power over those four days. It could be as long as eight days if you use power in the meantime, or even a dozen days in periods with much cloud cover.
Doubling the number/area of panels but still using four batteries would get you through a winter much better and safer. There is some power (up to 100 watts with my eight panels) even on overcast mornings, and overcast afternoons can get as mush as 200 watts, enough to power the fridge and freezer both.
Again, batteries need to be brought up to a full charge every so often. This is a major trib problem if one can't operate a generator to charge, resulting in badly sulfated batteries through repeated cloudy periods. The only murderer I've heard of, of batteries, is this creepy thing called, sulfation. The death of a battery occurs when the battery acid turns to sulfate on the lead plates and sticks, not turning back to battery acid as it usually does. As I understand it, sulfation is a normal process occurring during the discharge process, while the recharge process turns the sulfates back into normal acid material. Under certain conditions, the sulfates get too hard to be dislodged from the plates by the recharging energy. Some of the cells may sulfate more than others.
If you're going to go solar, get a propane generator too. It can be used for other things, like your water pump. Unfortunately, propane generators cost more money. My particular generator (on the small side) can get more than twice the wattage into the batteries than the solar panels on a summer day, meaning that the generator can be more helpful in getting those sticky sulfates burned off, especially in the colder months when the batteries are more prone to sulfation, and when the panels are producing at their worst. See "equalization," a process you're sure to hear about as you inquire on solar energy. It's nothing fancy, just a stronger stream of energy (at 31/32 volts) into the batteries every few months, or as needed, to help maintain the good health of the batteries.
I succumbed (even though I had been warned) to the temptation of purchasing a cheaper ($1,100) generator (brand = "All-Power") made in China (reliable brands cost $2,000-5,000 for a comparable 6-kilowatt unit). I had ridiculous breakdowns right away. For example -- and this is a good lesson passed on to you -- it had a plain, non-reinforced (i.e. no fibers/threads in the rubber) water hose (!) acting as the propane hose, and it cracked after three months in the cold. All the propane in the tank was wasted out the crack, something that you MUST prevent in the trib if all you have is the one large tank of propane. You don't want to lose your entire trib supply of propane for a faulty hose...blasted Chinese! Do not under any circumstances buy anything of trib-importance from China, unless its egg rolls. AND, shut the propane supply to the generator off when it's not in use, even if you purchase a reliable generator brand. If I've insulted the Chinese, then let me also insult the white industrialist: you make lousy egg rolls.
It might be a good idea to have three sets of batteries, one for each year of the trib, so long as they are re-charged from time to time over the long periods when sitting around waiting to be used. It all depends on how much you value your electricity, and how much money you have to spare. If others will come to live with you, you could then use more freezers, and the extra sets of batteries will be very useful then. Batteries should last about ten years, but can be ruined in as few as two if the operator doesn't know how they work, or doesn't keep an eye on them.
A large generator available in the trib might prove crucial for having strong electrical currents that your AC provider, called the power "inverter," cannot provide. Your system will only be able to provide, in AC power, what its inverter can provide. The higher the provision, the higher the inverter cost.
You can use the DC power straight from the batteries as easily as hooking two wires to two battery terminals and to your end use. If your four batteries are wired like mine in a 24-volt system, you can yet get 12 volts from them by connecting one wire to the positive terminal of one battery, and to the negative terminal of the battery directly beside it. If the latter wire is connected to the next battery yet (three in all between the two wires), you'll get 18 volts. While that voltage is not needed for most things, my laptop works on 19.3, and should work on the 18 too (I normally use a DC-to-DC converter ($150) to convert the 24 volts to 19.3).
However, if for example you use two of the batteries to get 12 volts, you will drain those two more than the other two batteries, and this is not good. Therefore, if you must use 12 or 18 volts, do it sparingly until all batteries are re-charged. After that you can do it again, sparingly.
I do not need the generator all spring and summer long. But you might. The message here is that you shouldn't necessary think that you'll be using a generator at all times to maintain battery health. In my area, the months of October through to the end of December are heavily clouded, compounded by the sun lower in the sky at that time. The winters, when the snow covers the panels way up on the roof, is when the generator will be most appreciated and hated. But as yet I haven't spent a winter in this house while the panels have been on the roof. Depending on how low the batteries are, the generator runs on about 75 cents per hour of gas for precious little electrical power in return. On the good side, a couple of hours of generator use can get me by for as much as three days if I use the computer and lighting alone. In a trib situation, computer use will probably not be demanding / heavy.
The reason that I've got the computer and lighting on direct DC battery power is that the inverter (Outback 3524) uses about 100 watts to provide 50 watts of power for the computer, and about 50 watts to provide for one 20 watt (fluorescent) light bulb. In other words, the efficiency of this large inverter is bad when providing low current; it's only when the power is in the hundreds of watts that its efficiency rises to about 95%. By contrast, the small DC-to-DC converter used for the laptop works on 95% efficiency while the Outback 3524 achieves only 50% efficiency for providing the laptop's 50 watts. I therefore get more than twice as much usage for computer and light bulbs from by-passing the inverter and wiring them instead in DC.
There are no tables I could find online that tell of the Outback product's efficiency at low power supplies, and this may be due to the bad press that it would receive should it show the figures. But I was told by an Outback employee (in a telephone conversation) that the 3524 inverter is 50% efficient when using a total of 50 watts. That's why I went to DC direct for the laptop.
The obvious question: why don't I get a small inverter dedicated to the fridge, and another small inverter dedicated to the freezer? After all, the freezer runs alone at times, and the fridge runs alone at times, both using much more power from the batteries than they actually operate on. I estimate that the 80 watts used by the freezer requires an added 40 or 50 watts to operate the 3524. When the sun is shining, who cares? But in the fall, this waste to the inverter will be very meaningful. When the fridge and freezer operate simultaneously, they use a little over 210 watts, at which time the efficiency of the inverter is much better, meaning that it's better when the appliances run at the same time. I figure that the inverter is still wasting as many as 60 watts to provide the 210 watts. Therefore, it may be a good idea to bypass the 3524 altogether, through a smaller, more-efficient inverter.
Whether to go solar in the trib is a tough decision, but an even harder one is whether to go solar before the trib. On the good side, you can start to pay for the solar system now by the money saved on the grid...if your generator usage doesn't eat up all that's saved. The cost of a propane tank adds still more to the cost of the gas inside it. You may or may not already own a tank, but for many these combined costs may get to the point where using the money to buy foods instead, before the trib starts, is more preferable than the solar system.
How about having many small barbecue tanks for generator use exclusively, as well as your own large tank for other uses? For safety reasons, barbecue tanks can only be used for so many years, and people dispose of the barbecue type even though they would likely go on working fine (without leakage) for many more years. How does one get several of them? Ask the hazardous-waste disposal site? Maybe Home Depot has a few aging tanks with little time left on them.
What if someone living on your property needs gas for a stove but he/she is situated hundreds of feet or more from your large propane tank? That's why it's good to know how to fill small tanks yourself. The website below tells how, and claims: "It's perfectly legal to refill them for personal use, however."
You might like to go solar as soon as you see the anti-Christ in the first half of the trib. I think that's a good plan. If you start three years before the skincode arrives, you'll be experienced in solar power for when you need to be, and your batteries should easily live until the end of the 1260 days. There are short-life and long-life batteries; the longer they live, the more they cost. If you buy seven years ahead of the rapture, buy for a 10 or 12 year duration so that you can abuse them a little without their dying before the seven years are up.
Batteries don't live for x amount of time, technically, but have a maximum number of re-charging cycles before they become practically useless. The life of my batteries are rated in the ballpark of 1000-1200 cycles when regularly depleted to half capacity. If I do one cycle per week to 50% depletion (on four batteries), I get about 1000 weeks, or some 20 years. Therefore, one who aims for a lifespan of seven years in 1000-cycle batteries should use no more than about two such cycles per week, for an estimated lifespan of 10 years. If you're running a small fridge and a freezer each at 1000 watt-hrs daily, you'll be doing about two cycles weekly. If you have eight batteries, you should be fine with more peace of mind. The trib rule should be: use as little battery power as possible today so that batteries are not threatened as much for the many tomorrows.
And that's another reason to get more panels, because panels last for many more years. You can arrange to use your electric needs mainly during sunny periods and use no battery power whatsoever at those times. Inverters are designed to automatically use panel power first, and dig into battery power only if panel power is insufficient. If you're going to use a high-watt appliance extensively, and you have the choice of midday versus dawn or dusk, you know the right choice.
Caution. Inverters can provide only so many maximum watts at any given time. Mine (Outback 3524) can provide up to 3,500 watts at any time there's demand. You might not be able to use a 20-amp hand-held circular saw if your inverter can only get you a maximum of 2,000 watts. Either get a circular saw that operates on less power, or make sure the inverter is built to handle the load.
'm sure that power tools do not use the same wattage at all times. For example, my 20-amp saw does not always use 20 amps (= about 2400 watts); it might use a few hundred watts when running freely on no material; 1,000 watts when cutting thin plywood; and 1,200 watts when cutting 2 x 4s. Or, the harder you push the saw, the more power it will use...meaning, on the up-side, that if your inverter can't generally handle a certain tool, you may be able to use the tool more lightly and get away with it...if the inverter's breaker is not tripped when turning the tool on. My 20-amp saw does not trip the breaker to the 3524.
The sales people say that we can't combine a new battery pack with an aging one without some damage / diminishment to the new pack. Just so you know to inquire about this (the Surrette battery company allows the addition of new batteries when the others are not more than a year old). I don't yet know how extensive the adversity is when adding new packs to aging ones, but in my case, I decided to keep the two sets of four batteries separate from one another. I suppose that one could age the new pack for a while until both packs can be linked together.
Using two separate battery packs requires a transfer switch (mine's "home-made" using an inexpensive DC switch available at auto-parts stores) between the batteries and the solar-panel charger, meaning that only one set of batteries can be charged at a time...unless an extra charger is installed to charge the second set, in which case one needs to split the full number of solar panels into two separate circuits. I have the eight panels separated into two circuits, and use two chargers wired in such a way as to use four panels to charge four batteries simultaneous with the charging of the other four. There are times when this option is much appreciated, when both sets of batteries are on the low side, and a day or two of sun appears after days of cloud.
Another benefit to having two sets of batteries is that eight batteries, when low, require twice as much sun to bring them back to a healthy condition, but sunlight may not be sufficient at times to do so. But if the available sunlight is used to charge only four batteries, the advantage is obvious. The other set of low batteries can be left unused and uncharged until more sun appears.
The disadvantage to having two packs of batteries is that an extra inverter (i.e. much more cost) is best for accessing the second set. The option is an appropriate transfer switch (not from the auto-parts dealer) allowing the connection of the one inverter to either battery set, but not both simultaneously...meaning that AC power can be accessed from only one battery pack at a time, which could be an ongoing headache. In such a case, you should wire all the around-the-clock needs, such as fridge and freezer, to one battery pack, but then decide what needs will be on the other battery pack. If the stove / microwave and all receptacle plugs are on the second pack, you'll need to flip the transfer switch every time the stove is used. It means that you'll be much happier putting the stove on the same battery pack as the fridge and freezer, but the problem then is the heavy usage of the one pack and light usage of the second pack. It's would be ideal if both packs split the household loads equally so that the one pack isn't running low more often or too quickly.
This is where some small (i.e. inexpensive) DC-to-AC inverters (see webpage below) can come in handy that bypass the large inverter-charger needed in solar power systems. One can't get small inverters to run things like ovens, but a fridge or freezer using just 150-200 watts can have an inverter (in 24 volts) for under $150. The higher the wattage needs, the higher the cost, so that a 1500-watt inverter in 24 volts is over $400. The least-expensive inverters are for 12 volt systems, but I read that arranging a solar system on 12 volts is not the best option.
My situation is one 3524 inverter, not on a transfer switch because I use one battery pack to power the DC laptop and DC lighting exclusively. The 3524 machine is called an "inverter-charger" because it not only converts DC to AC, but charges the batteries (i.e. regulates charging input power) when using a gas generator (the inverters at the page above wouldn't have that ability). By not having a transfer switch, I can't charge both sets of batteries with a generator...unless I disconnect (with a wrench) the very fat inverter-charger wires from one pack and connect them to the other pack, something that can be tolerated only so often (once or twice annually would be "nice," if possible). However, for trib purposes, it would be ideal to have both battery packs available for AC use, on a transfer switch, that is, meaning that one inverter can then be used to charge both packs with a generator (i.e. with no need of the nasty wrench method).
If one goes with two inverters, there's a clear advantage in that small converters / inverters at each device / appliance may not be required. One wouldn't need two expensive inverter-chargers, but only one for providing high demand in case it's needed. The second one would be the smaller, everyday inverter providing lighter usage without much non-efficiency waste.
For example, a 700 watt inverter on the electrical-panel wall (i.e. beside the larger inverter) would run the fridge, freezer, lights, and most other appliances in the evenings. This 700 watt inverter (90% efficient) lists for only $276. It claims to have surge protection of 2,000 watts for about a half second, meaning that turning on a shop-vac won't likely trip the breaker. It can also handle 1150 watts for three minutes, meaning that you may be able to use a toaster without tripping the breaker. You wouldn't want to trip a breaker (as the well pump might without your knowledge) and forget to re-set it because your fridge and freezer would be off all night, or longer. The 1500-watt inverter (handles 3,000-watt surge) is less problematic in that regard, and is roughly the same in efficiency (well worth the extra money if needed). These inverters (I'm not recommending them versus other brands / types; I haven't used one) are made to run off of store-bought batteries, but of course you would use your solar batteries instead (which, I assume, is no problem).
Still, the question of whether it's best to have all eight batteries on one pack (very convenient, less expensive), or to divide into two packs (has some advantages), is one I haven't answered yet. But then, I have never had all eight batteries linked to one system in order to see how problematic it is to re-charge them in times of low sun. If you're in the sunny south, it's a no-brainer: go with all eight batteries on one circuit, in either 24-volt or 48-volt configuration (just don't purchase a 3524 Outback inverter for a 48-volt system). But for northerners and north-westerners, the cost of the transfer switch may end up being less than the extra gas needed in cooler months to re-charge the eight batteries with a gas generator, and in the meantime you'll have more wear-and-tear on the generator.
Check with the solar-power people or an electrician before wiring if you're not confident in what you're doing. Two transfer switches side-by-side will be needed in the case of two inverters and two battery packs. One transfer switch decides which inverter is in play, and the other switch decides which battery pack is engaged. Both transfer switches must be heavy enough to handle the maximum load, in DC power, to the largest inverter.
Becoming a solar-power governor is a little like raising infants into adults. The first and only time that you do it is your training session. Flunk the first time, and there's no chance to get it right the second time.
Don't trust sales people in this business without putting on some smarts of your own. The solar industry is hard-up, and needs to hide some truths to get people to buy. You probably won't get results as rosy as promised.
On many evenings, after the fridge and freezer is shut off for the night, we won't need any power aside from solar-friendly light bulbs and, perhaps, water pump needs. Even one 9-watt fluorescent light bulb can be sufficient to light a typical room for most purposes. I used one bulb for plenty of light at the computer desk, equal to several candles. A 20-watt fluorescent bulb (about $10 in 24 volts) lights up my entire open-concept living room and kitchen (700 square feet), and my eyes quickly adjust to what the average person would consider "dark." There are very expensive (about $25) 3-watt bulbs in 12-volt systems that give off plenty of bright-white LED light (of the "cold" light type that science labs might use), which can be used in 24-volt systems (so I've been told) if two bulbs are used in one circuit, and if the circuit is wired properly (instead of the black wire from one bulb going to the black of the other, run the white wire of the first to the black of the second, and the white of the second to white-wire bar in the panel box). But if one bulb goes out, or is unscrewed from its socket, the other bulb will blow (i.e. both bulbs are needed to handle the 24-volt load).
When I contacted Outback, tech-help said that an inverter-charger smaller (allows 2,000 watt demand) than mine has only about a 50 percent efficiency when the demand is 50 watts. In other words, when I'm using 40 watts on the laptop, and 9 watts in an AC bulb, and that's all that's being used at the time, my 3,500-watt inverter-charger is soaking up more than two three times the 49 watts. Looking further into this, the story got worse. When using just 20 watts total, the efficiency of the 2,000-watt inverter drops to about 15 percent, and when using only 10 watts, the efficiency is just 5 percent. My math tells me that, if the entire family is in one room with one 9-watt bulb being the only electrical usage at the time, a total of 180 watts would be eaten up by the inverter to produce 9 watts AC, and that's not including the 20 watts to run the inverter.
My small air fan used for cooling in summer runs on 30 watts at its middle setting, meaning that it's using perhaps 100 watts in reality. If I leave it on much of the evening, it wastes significant energy. There are many gadgets now, using less than 10 watts that may waste 100-200 watts. Consider the phone message system that needs to be on at all times, or cordless telephones (yes, some people still have one). Therefore, arrange the electrical usage to feed straight from the batteries, or, where the usage is not at 24 volts, from batteries through smaller inverters with ball-park 90-95% efficiency.
One may wire light bulbs in a separate DC circuit system, straight off the batteries, to forego the power-sucking inverter-charger, as well as any inverter. You can't get better efficiency than that. Technically, it doesn't matter which of the four-battery packs are used. Start off with an extra panel box for the DC system, and run its two wires: 1) straight to the negative battery terminal of a battery at one end of the four-battery string, and, 2) to the positive terminal of the battery at the other end of the string. Each wire from the panel box to a light bulb circuit is to be on a 15-amp breaker, and so far as I can tell, there is no difference between the breakers in the DC box (purchased from a solar-power store) and the 15 amp breakers at Home Depot. I'm assuming that 15 amps is 15 amps regardless of the voltage, but check before you buy breakers for your DC box.
If you're building your own house, wire DC to a few (or many) DC receptacle plugs for use in small gadgets / appliances if need be. To wire DC, just use larger-gauge wire, the size depending on the voltage and the distance run. The lower the voltage, and the greater the distance, the larger the gauge needs to be to avoid voltage loss (bulbs will still work at reduced voltages, but will not be as bright). For my 24 volt system, laws in the area required 10-gauge wire (smaller at the far ends of the circuits feeding the last bulbs) instead of the standard 12 or 14 gauge (10 is larger, i.e. thicker copper wire, than 12). This is one reason that a 24-volt solar system is better than a 12-volt. It was absolutely no big deal to wire DC to all lights and a few plugs, and the larger wire is fine (safer, even) if I or someone else decides in the future to wire all lights to the AC panel.
The good news: in many shorter runs to my lights and plugs, 12-gauge wire would have been fine, so that your house may already be wired acceptably (for a 24-volt system) to many lights and receptacles. If you go with a 48-volt system, chances are that your existing wiring is fully acceptable for DC use throughout the house. A 48-volt system is nothing but eight batteries wired together, negative terminal to positive terminal, across all batteries. If you want to use a 24-volt system with eight batteries, wire the fourth battery's positive terminal to the 5th battery's positive, and the fourth battery's negative to the 5th battery's negative.
A quick look online shows that up to some 71 feet of mere 14 gauge wire can be used to wire any item using 3 amps (= 75 watts) on a 24-volt system. That should reach any part of the house if your electric room is central, and larger currents would be no problem using 12 gauge wire. See chart at: http://www.powerupco.com/technical/24VWireSizing.pdf
When Sun is Scarce
As you can see on a sun-hour map (end of page), the best places for solar power are in the western United States, west of and including Texas, while extreme-western Canada rates amongst the worst. Extreme-western Canada is not very cold in winter (for refrigeration purposes), and has high humidity (it rains nearly every day in some places, and I mean six days a week for nearly the entire winter) that can spoil the garden harvest quickly if not refrigerated. You might decide wisely not to have a trib retreat in that area, but then there are ways to off-set these problems.
In a trib situation, you might like to have your solar panels on/near the ground rather than on the roof. That's because trib survivors are not going to be inconvenienced to turn the panels by hand toward the sun in the morning, then turn the panels toward the sun at noon, then turn them toward the sun in mid afternoon. People who hold jobs daily can't appreciate this inconvenience as we would in the trib. They might purchase an automatic solar tracker instead. However, it is said that including just one or two more panels gives as much additional power as a solar tracker. Even so, if you have your panels on a pole in the ground, and you have arranged a method of spinning the pole, you have that option in the trib to maximize power when you need it.
You can even have your panels on a platform equipped with simple hinges so that you can change from a winter angle to a summer angle, though if the angle is fixed (unmovable) in-between the two positions, it might be just dandy. My angle is fixed on the roof, and favors the winter slightly (when it's needed most) more than the summer. I've installed mine high on the roof because I have tall trees. My roof slope is 16 feet up for every 12 feet across, or about 52 degrees.
I've used a unique system allowing the melting of the snow on the panels at will. Instead of installing the panels over the shingles, panels were laid over horizontal 2x4s nailed to the roof rafters. I plan on covering the bottom side of the rafters with a waterproof board of some type so that an enclosed space will exist under between the board and the panels. I can then bring a furnace duct to the enclosed space, and run slight (not ferocious) furnace heat into it when it snows. I'll arrange to shut the duct when I don't need to warm the panels. Too much heat in dire cold could crack the panel glass.
Of course, there is silicone-caulk between panels, and all around them, to keep rain out of the attic. For the little rain that may get in (none has yet, over four three), and for the high humidity that will develop when heated air hits the undersides of the panels, I'll have a water catchment of some sort below the panels. I'm also water-proofing the roof rafters and 2x4s in the enclosed space, as they will accumulate condensation throughout the heating process.
I've got to do remove the snow with heat because the roof is too steep for getting on with a snow shovel, and the panels are too high to reach with a long tool. The point is, if you're not in tropical zones, you've got to deal with snow on your panels. I've left a small space between the two sets of panels, where I can get up on the roof with a long-handled shovel, but it requires removing a lid between two panels, and getting snow down the neck as I climb out. I would rather let the heat do it for me, and climb out only in heavy snowfalls.
There is the problem of creating an ice bar on the roof at the lower end of the panels as snow on panels is melted repeatedly. It may not be possible to melt one or two feet of snow more than once or twice if the melted snow doesn't run off the roof as water (I've yet to see what results I get). But for those light snowfalls that can cover the panels for weeks at a time if the temperature stays cold enough, heating panels is the way to go. It would be ideal if the heated enclosure caused snow flakes to melt as soon as they hit the tops of the panels.
I've bought another generator after the Chinese model broke down almost instantly, a 2,400 watt Yamaha. It runs on gasoline but can be modified to propane for about $200. It's more expensive (about $1,300) than other gasoline models because it's an inverter generator, i.e. it has the ability to run slower, and therefore use less gas, at those times when the electric load is lighter. The generator is extremely quiet, no toleration needed, and starts in extreme cold.
Gasoline may be out of the question for long-term trib use, as it supposedly has a short shelf life (this may be more globalist rumor than reality, but I don't want to take the chance in stocking up on gas in case it's reality). Propane is the way to go, but propane generators cost a small fortune, so you may do what I did, buy a gasoline generator that can be modified to propane:
"Our do-it-yourself change over kits allow you to run your Honda gasoline generator on propane, natural gas, or all three. Your engine will last longer, start better in cold weather and even start next year when you go to use it in an emergency...
...If you have propane available you probably know you can store propane for years. It does not gum up, go bad, or pollute the air like gasoline does. Use the little bar-b-q grill type cylinders as shown above or up to the 1000 gallon ASME tanks."
The following webpage is not a Yamaha dealer, but promises to provide me with a tri-fuel carburetor kit, allowing the machine to run on any, gasoline, propane or natural gas at the turn of a switch:
"...You could run the generator from the [small propane] cylinder while camping and then, when you come home, you can connect the same generator right into a natural gas line or just fill the generators gasoline tank and run. That's right. It's as simple as turning one fuel off and the other fuel on."
Here's the tri-kit and how it works.
Don't confuse an inverter-charger with an inverter generator. The inverter-charger (e.g. the 3524 Outback) is what the electricity from any generator goes through before entering the batteries. The inverter-charger automatically (as soon as the generator is started) routes the power to the batteries in a safe way (i.e. that won't damage the batteries). As the batteries fill up, less and less power is permitted in, at which time you might do your laundry, for example, or run other items using electricity, since, after all, the generator is running anyway; all household power from the inverter-generator at that time will automatically come from the generator instead of from the batteries.
My Chinese model ruined two computers, but Yamaha claims that its inverter-generator won't harm computers. You run the risk of damaging sensitive equipment when run off of the generator.
For your health and safety, get a tiny exhaust fan (runs on 5 watts or less), built for the purpose, to blow the air out of the battery casement. Hydrogen and oxygen (a highly-explosive mix) will come out from the batteries while charging, and so you want a sealed casement to keep the gases from getting into the house and your lungs. But you don't want the gases to build up in the case. Typically, a small pipe (2 inches, or larger for larger systems) going outdoors is provided from the top of the case, and an exhaust fan is installed in the pipe to facilitate the removal of the hydrogen. A second pipe to the outside allows clean outside air to replace the toxic air going out.
The exhaust fan (about one inch in diameter is needed for four or eight batteries) is wired to the inverter-charger, which starts the fan at a certain voltage setting of your choice, say 28.5 volts for a 24-volt system. In this way, the fan won't run on cloudy days or other sunless periods when batteries are not charging. The fan will turn on only when charging is high (at which time the power to run the fan is free from all the sunlight).
Make the height of your battery casement easy for checking the battery cells. I have the top of the case (i.e. the lid on hinges) at chest level so that the specific-gravity meter dipped into cells is at eye level. No stooping required, and you'll love me for it because you're going to hate checking the cells whether you stoop or not, and even on a good day. You're going to be checking the specific gravity (= the weight of the battery acid as compared to the weight of pure water) of cells regularly (pity the solar monkeys who have dozens of batteries), and the more you like the look and smell of roses, the more you're going to hate the look and smell of the battery casement.
Alas, if you become a solar-system master, you're not going to be God at all. You're going to be a mere student learning. You'll learn that the health of each cell is like an individual patient at the doctor's office who returns again and again to grip about threatening chest pains. If you don't deal with cells going bad, they'll have a lethal arrest right under your nose.
You're going to learn that the voltage reading of the batteries (shows on a digital display of the charger) is not necessarily an indication of the state of the battery acid. If only there were beautiful things inside those battery holes. Alas, the state of the cells has to do with the state of the acid, and no one that I know of loves battery acid, not even to look at. You as the acid doctor will need to assure that the acidic material is afloat (i.e. dissolved) in the water rather than crusted on the battery plates.
Which do you like better, the thought of sick crusted sulfates on sunken lead plates you have never seen, or a healthy, bubbly solution that can burn your eye-balls out? If you're going to have your specific gravity meter at eye level, you had better be very careful not to flick some of it toward your face. I do not wear glasses when doing this job, but sooner or later, that container of water I keep filled with clean water near the batteries will be poured all at once into one of my eyes...before the acid burns too deeply.
I'm sure you'll want the risky, healthy solution rather than the sick crusted plates, and for this cause you will open the battery-case lid over and over again to take the acid readings. You will be informed by the battery manual why you are checking the acid, and how to repair it when it goes bad. The gaskets you use to seal the lid must bounce back (some call this "memory") when the lid is opened so that, when it's closed again, the gasket material will be pressed to a degree. Otherwise, if the gasket material does not bounce back (or grow), the seal will not be tight/ideal. There are mental problems that can arise when you've breathed in the products of battery cells. That little exhaust fan can save millions of brain cells, but even when the fan goes off, some cell evaporation, with fumes, continues to exit into case because the acid is active and warm from the charging process.
If you build your case in such a way that hydrogen can get into the walls of your house, a wall, ceiling, or upper floor could go kaboom at any time. Or, the hydrogen, having no odor, could get into the house. I'm not trying to scare you into for-going the solar-energy option, just urging you to get the case built well. Or better yet, invent a new way to preserve energy that doesn't involve batteries.
For all you techies, it's not easy to find an article with a chart showing the reduction in solar energy on solar panels depending on the angle of the sun in relation to the panels. But there's one at the article below.
I came across this: "Since Energy is transmitted and measured in Watts per square meter if you are getting 100 watts from a panel that is one square meter and turn it 45 degrees away from the sun the effective surface is Area divided by 1.41 Reflective losses from the glass are not counted in this but will increase also." My understanding here is that the sun shining at a 45-degree angle is not half the energy as one might assume, but 1 / 1.41 = 71%, which is really pretty good. The chart above shows a 30 percent loss at a 45-degree angle.
The chart at the page below tells that a tilt angle 30 degrees away from the optimum angle reduces annual power by 11-12 percent, while a tilt angle of 60 degrees away from optimum reduced annual energy by 44 percent. The loss is just 3 percent at an angle 15 degrees from optimum, even though light energy is reduced by about 6 percent at that angle. However, these figures appear to be from actual test sights, but then available solar energy from test to test (i.e. year to year) is never the same. What we need is a chart showing how much energy a solar panel in the lab receives depending on the angle to the light source, but as these charts are ever so scarce (I can't find one), I'm suspicious that figures can be manipulated or falsely reported to advance the sale of solar trackers.
For example, what if all solar panels are such that they absorb less energy than expected, when the sun shines more directly upon them (say between 45 degrees and straight on), due to interference with the "splash" of electrons bouncing out of the panels toward the sun? In such cases, while there may be 31 percent less light at a 45-degree angle, there may be significantly less difference between what a panel can produce in 45-degree light versus what the same panel may produce at straight-on light. If this is true, then solar trackers may not be as beneficial as they may be cracked out to be by tracker providers.
The reduction in solar energy when shining on a surface at an angle has not, as we might at first assume, have everything to do with increased reflection of light away from the panels. It has mainly to do with less light volume striking the angled surface. For example, lifting a sheet of anything lying on flat ground at midday will reduce the total light per square area on the sheet, until there is zero light when the sheet is stood straight up. If you draw this on paper, you'll see why. When the sheet is lifted to a 45-degree angle (where the ground is zero degree), it receives roughly 71 percent of what light it received when lying flat. When the sheet is lifted to a 60-degree angle, it receives just 50 percent of the light.
I didn't know the following, or at least I hadn't read anything so drastic on tree shading of panels, until my fourth year of owning a solar system:
If even a small section of a photovoltaic panel is shaded - for example by the branch of a tree - there is a very significant drop in power output from the panel. This is because a PV solar panel is made up of a string of individual solar cells connected in series with one another. The current output from the whole panel is limited to that passing through the weakest link cell. If one cell (out of for example 36 in a panel) is completely shaded, the power output from the panel will fall to zero. If one cell is 50% shaded, then the power output from the whole panel will fall by 50% - a very significant drop for such a small area of shading.
...Bypass diodes can be connected between panels in a system, and also between groups of cells in a panel so that the only power loss is from the shaded portion.
If that's true on what shade can do, you had best know about it, especially if you have snow. But the writer didn't mention that it's so-called "hard shading" that has such adverse effects:
Shading obstructions are considered "hard' when objects are in direct contact with the glass...Bird droppings, broken tree branches and wayward frisbees are examples of hard shading...Partial hard shading of one cell in a photovoltaic panel can create a power drop as much as 50%...
...Most manufacturers use bypass diodes...
Whew. I must have diodes already installed. I'm hoping anyway, as I have lots of snow and a few trees. Keep in mind that the writer(s) above are seeking to sell things, perhaps exaggerating the fears.
The article above has a chart showing that it's the voltage, not amps, that drops with temperature increase on the panels. In my thinking, heat around the panels has similar interference effects on in-coming light as do the splashing electrons, and the latter create some heat.
Should we or shouldn't we ground the batteries to a ground rod / plate? One electrical place I called, though not selling solar, said that batteries don't need to be grounded, but the article below recommends it.
My thinking was that lightning would be more attracted to the metal frames of the solar panels if they are more positively charged, which is why I temporarily disconnected the ground wire at the electrical panel when lightning storms approached. But now I'm reading:
...Lightning does not have to strike directly to cause damage to sensitive electronic equipment, such as inverters...It can be miles away and invisible, and still induce high voltage surges in wiring, especially in long lines [lightning turns my computer on even when it's far away and quiet]. Fortunately, almost all cases of lightning damage can be prevented by proper system grounding...
...During lightning storms, the clouds build up a static electric charge [sounds negative to me]. This causes accumulation of the opposite charge in objects on the ground. Objects that are INSULATED from the earth tend to accumulate the charge more strongly than the surrounding earth [sounds like he's saying that ungrounded items tend to go more negative, which in my mind helps to prevent a lightning strike]. If the potential difference (voltage) between sky and the object is great enough, lightning will jump the gap [who's right, me or him/her?].
Grounding your system does four things: (1) It drains off accumulated charges so that lightning is NOT HIGHLY ATTRACTED to your system. (2) If lightning does strike, or if a high charge does build up, your ground connection provides a safe path for discharge directly to the earth rather than through your wiring...
Perhaps he's correct in saying that lightning strikes between two negative points. My understanding has been that electricity runs from negative to positive (except in the case of batteries, because when they first assigned positive and negative in the pioneer days of batteries, they got it backward, and the establishment kept it backward to this day, meaning that the positive terminal of a battery is really the electrically-charged, or negative, terminal, which is why the negative terminal is to be grounded...to the positively-charged, wet dirt). The article recommends much more grounding for solar systems than what the laws require, and makes the good point of assuring a wet place for the ground rod / plate / wire.
Here's today's lesson on lightning:
...The details of how a cloud becomes statically charged are not completely understood (as of this writing)...[that's because evolutionists opted to wrongly believe that heat is not the same thing as the free electron... released, for example, when water particles come together]
The precursor of any lightning strike is the polarization of positive and negative charges within a storm cloud. The tops of the storm clouds are known to acquire an excess of positive charge and the bottoms of the storm clouds acquire an excess of negative charge. Two mechanisms seem important to the polarization process. One mechanism involves a separation of charge by a process that bears resemblance to frictional charging. Clouds are known to contain countless millions of suspended water droplets and ice particles moving and whirling about in turbulent fashion. Additional water from the ground evaporates, rises upward and forms clusters of droplets as it approaches a cloud. This upwardly rising moisture collides with water droplets within the clouds. In the collisions, electrons are ripped off the rising droplets [no, not ripped off by physical erosion, but whenever any materials come together, electrons are released], causing a separation of negative electrons from a positively charged water droplet or a cluster of droplets.
Note that there is no lightning in cold winters or cold months, which is clue that heat is the culprit. The point is, lightning is believed to be a negative-to-positive train, not negative to negative. Therefore, should I temporarily disconnect the ground wire from the solar panels on the roof during storms? It makes sense to me.
When my inverter was just two years old, one of the boards suffered a fatal blow. It may have been due to lightning, but I can't be sure. Your tribulation solar system can suffer such a thing at anytime. Lightning arresters are available.
Here's an article on battery charging.
Here's a site for checking out generators and other solar-power ideas:
See the website below for a U.S. sun-hour map and other information.
http://sunelec.com/index.php?main_page=page_2 There's a global sun-hour map at http://lreese911.tripod.com/sitebuildercontent/sitebuilderfiles/solorpower.pdf