Having owned a small solar system for nine years as of 2017, I have a few things to say with a tribulation outlook. 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. And it's far better to enter the trib a little experienced on how to use the system best. The risk in buying early is obvious, since you don't know for sure when the Time will arrive. 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 slower to make the leap.
Having a solar system isn't complete security, anyway, as the equipment can break down. I purchased Outback equipment, and have seen two computer boards fry (both in the inverter), the first one in less than two years, totally unexpected because the inverter can handle a lot more power than I usually demand of it. It stinks, but having extra boards seems like a good insurance policy. Or, ask which board is most likely to go. For me it was the same board twice, the one with the large tubes, whatever it's called.
Outback uses its mother boards over and over. When they send me a "new one," they demand the old one back, and claim to refurbish it, but, obviously, there are resistors / capacitors and other items in the unit that are aged, and these units go out that way to other people, with certain break-down predicted at any time thereafter. Outback tells me that so long as the mother boards are in working condition when they receive them back, they go out that way. Shame. They give a five-year warranty on mother boards in a newly-bought inverter, but only 90 days in a refurbished unit. What's that tell you? This is an underhanded way for Outback to supply itself with extra money, but for us, it's a high risk. If you trust Outback, you can buy a new board as an extra. In 2016, the boards I needed were about $500 new, and half that refurbished. I'm not sure I believe Outback when they say that every new inverter comes with brand-new boards.
I was "fortunate" when the electric company wanted about $12,000 to install power to my new property. It turned out that there was no choice but to go solar at a cost of about $9,000 U.S. that included eight 130-watt solar panels and eight 530-amp batteries, which is considered a small solar system...but it's borderline-enough for me alone, though it's a curse to be sure. I installed the system myself, but if you can't, it's yet another expense. If you're handy, you can use the manuals to install most of the system, then call an electrician in to make sure you've done it all correctly.
The threat of less-expensive, thin-film panels has pushed the cost of silicon 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 rumors originating from silicon providers). The bottom line on efficiency is how much money it costs (to purchase and install the system) per watt of power absorbed from the sun. Silicon panels last 20 years or more, but we won't need them for that long. Should we buy used panels? I've been meaning to ask someone whether panels deteriorate in the sun when not being used, but haven't gotten round to it.
http://www.saveandgenerate.com/reports/MicrogenVoice1.pdf (webpage not there last I checked)
Inexpensive thin-film panels should prove to be advantageous for tribulation survival. The film doesn't last as many years, nor capture as much energy per area, but for trib purposes, who cares? We should look into thin film absolutely.
Batteries are still fairly expensive (mine were about $250US each in 2008). The good news is, we shouldn't need many batteries, and they last more than four years, so long as they are not abused. The battery charger (or charge controller) was $400, and the 3500-watt inverter $1,600. After these expenditures, at current prices, you'll be off to races...as the turtle.
I have eight batteries but do with only four when it's not continually cloudy for weeks in a row. It's not a bad idea to have eight on hand, but to use four only, changing packs from time to time so that both get a work-out. If you ruin one pack from neglect, you'll have some power from the other. All eight of my batteries are in pretty good shape after nine years, mainly because I have used little power from them. The main threat: if you demand too much power from batteries when they are low in charge, it can reduce the performance of the batteries permanently or simply age them faster. The solution: don't use electrical power when the batteries have drained to roughly half-full of charge, unless the sun shines enough to handle what watts you are using at the time.
Four panels and four batteries can handle typical power tools for a not-bad length of running time on sunny days, but roughly only 30 minutes for a cloudy day if the battery pack starts off full in the morning. It's not likely going to be full in the morning. So, you will need to wait for sun. That's life as a solar turtle.
Four panels and four batteries can do a lot. Running a washing machine, no problem. Want music? No problem. The computer, 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 together, in non-winter months of a northern latitude, using just four batteries and eight panels.
Your main tribulation concern might be the water pump. It 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. Most of the power needed is due to the pressure tank; my pump runs something like a minute to get the last gallon into the tank, such a waste of power. In short, the power needed to get the first half of the tank filled is a LOT less than getting the second half. When I'm short of power, I just turn the breaker to the pump off after the tank is about half full. The breaker has been switched on and off hundreds of times without fail, saving my batteries for more life in the meantime. Pumping into an open tank takes far less power, and, in the trib, where life will not demand that you keep to a schedule (such as punching in the clock at work), you really don't need pressure at the taps.
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, and from that you can do the math to see how much power it draws per hour of operation, measured in so-called watt-hours.
For example, I use a small pressurized tank of about 15 gallons because the pump (about 700 watts) runs about four minutes trying to get the pressure from about 20 psi to 40 psi, and, as I implied, about a minute of that is to get the pressure from 38 to 40. The larger the tank, the more you waste power to get the pressure from 35 to 40. With a small solar system, you should not have a large tank...for which there really is no great advantage. Instead, just put the pump where you can't hear it. Four batteries can't handle the pump running very long when the batteries are low. Battery As the pump runs, the battery voltage drops if there is no sun shining. Therefore, you not only have the increasing pressure in the tank asking the pump to work harder as it fills, the dropping voltage makes the pump weaker. It's the perfect recipe for wasting power and battery life. For me alone, it's not a big deal, but if you have four or five people for each four batteries, it will be a big deal. You might start thinking to do away with the pressurized tank altogether, or at least have a non-pressurized water system for periods when the batteries and sun together are low.
A full and healthy 24-volt battery pack with no sun shining on the panels sits at 25.2 volts. When the sun shines, the voltage rises to about 29 volts. So long as the sun is shining high in the sky, a water pump could theoretically run continuously, reducing the voltage to, say, 26 volts, and holding it there (the batteries will be fine under this load). The sun will hold the voltage there because the pump is feeding off of the sun rather than off of the batteries. When the voltage dips below 25.2, battery power is being used, and, with use, the lives of the batteries are being used up too. So, theoretically, batteries will last forever if you never let them dip below 25.2. The point is, use electricity when the sun is shining, a no-brainer. If you provide large or many tanks for trib purposes, just fill them with water when it's sunny, a no-brainer.
If three days of clouds move in, and the battery voltage drops to 24.4 in the dark of night, the water pump becomes a serious issue if the water demand, coupled with other electrical demands, is great. Battery companies maintain that most battery damage (aging) occurs by bringing the standing voltage to much less than 24.4. Batteries can be ruined in a year or less by doing so too often and too deeply. On the other hand, if the voltage is at 24.4 and the only thing running is a 50-watt laptop, one can use it all day long and see no change in the voltage.
A battery at about 24.0 is "dead." But it's not really permanently dead. It can be re-charged for a certain number of times. But there is a limit on how many times the pack can be drained to 24.0 before suffering a fatal blow. However, if you see that the voltage meter has dipped below 24.0 during electrical usage, that is not the true, standing (not being used at the time) battery pack. Voltage drops drastically when electricity is in use, but this is not the true measure of the voltage in the battery plates. We can say that the voltage registered on the volt meter is a measure of the exterior edges of the battery plates; the interior of the plates has a lot of energy that can't get to the outer edges as fast as the energy on the edges is being used up. So, after the voltage drops below 24.0, it comes back up again soon after electrical use ceases. Don't worry.
I'm reading online that a 1 HP deep-well pump uses 8 to 10 amps, or about 1000 - 1200 watts (multiply amps x 120 volts to find watts). However, I'm also reading that 1 HP is equivalent to 746 watts. I'm assuming that the loss of power due to conversion of electrical power to mechanical causes the reduction to 746 watts (why isn't this an even or approximate number?). You might want to verify that before doing your math. If you can use a 1/2 HP submersible to lift your shallow water, and it's using 600 watts, I'd say you're in pretty good shape, but the deeper your well water, the larger the pump need. Again, you can manage with a smaller pump if, instead of stuffing a water tank under pressure, you pump into an open tank. They say that an open tank should be 45 feet above the taps for decent pressure, but my math tells me that 45 feet is equal to only 13 or 14 psi. From this, one can figure about .3 psi per foot of water height, meaning that a well pump 200 feet below tap level is under a water pressure of about 60 psi, and on top of that, you've got to add whatever pressure you set your pressurized tank at. That pump needs to work hard to get you a gallon of water. The solution: have rain barrels for when power is low.
One option is to set the pump to shut off at 30 psi instead of 40, saving an enormous amount of battery power. My pump gets the pressure to 30 quickly. It's only between 30 and 40 that the pumps takes a "long" time. If you're going to set the pump at 30 or less, put it where you can't hear it, because it's going to stop and start a lot more. And figure on enjoying showers a lot less. If you will be having a deep well, you should size your battery pack accordingly. The solar people can tell you what you'll need. Nothing else electrically is as important as your water supply.
Having an open tank(s) is a very good idea. You can have a shut-off valve (can be "dangerous") at the tank so that, when it's shut, the pump fills the pressure tank instead. BUT if you leave the valve open and walk away, the water pump will never stop running, and the open tank will overflow. So, when you fill the open tank, always shut the valve immediately afterward. Or, better yet, have an automatic valve that shuts off when the water reaches a certain level (such as the one in your toilet tank). Ask your farm supplier for one of these, because they are used to automatically fill tanks for livestock.
My four batteries can handle a toaster (about 1000 watts) for several minutes consecutively without dropping battery voltage critically when the sun is high. But that's because my eight solar panels (rated for 1040 watts combined) can produce 800-900 watts even when the sun is not at its best angle to the panels. My laundry machine can take up to 800 watts, but the eight panels can handle that near midday on sunny days. You can get by doing laundry with only 500 watts of panel power, borrowing the rest from the batteries. The laundry machine will be one of the least of your worries unless you are often low on battery power. I would not choose less than 1000 watts of panel power, if I were you, if money's not an issue on what you can or can not buy.
If you wish to water the garden for an hour or more, you can do it at midday so long as the panel power meets the pump requirement. If your pump uses 1200 watts, get about 1500 in panels, but more if you think you'll be watering the garden several hours at a time every few days. The good news, droughts and dry regions also have sunny weather. In a hot, dry climate, provide a drain in the rain barrel(s), and refresh it on any sunny day with well water. Or, dig a large hole(s), install a waterproof sheet of some kind, and fill the hole with water on sunny days.
A 130-watt panel provides about 130 watts when the sun's angle is straight on, when the sun's position is at its highest, and when the panels are new (they produce less with age). The further from the equator one's location, the less the panels can get maximum sun from a "high noon" position, albeit a position of one or two o'clock is nearly equivalent to high noon. Each 130-watt panel can only run two 60 watt bulbs, for example, at peak sun conditions. It's so precious little for a hundred dollars in panel expense.
In Canada, the sun on December 21 is significantly lower than 45 degrees. The amount of atmosphere that obstructs sunlight becomes significant between 60 and 45 degrees, but is critical at 30 degrees. Even in southern Canada, the sun reaches as low as the 30s. That's why Canadians will need a generator that will be sure to start at temperatures 10 below zero F. I purchased a new Yamaha model small enough that I can carry it into the house to warm up, if need be. In other words, if you get a monster compressor, used and unreliable, that won't fit through your front door, you may have a problem in winter. The Yamaha always started several winters in a row, but the makers left loose screws all over the place, not a good sign. One loose screw that I couldn't get to with tools on hand, after only about 60 hours of operation, required taking the machine to the repairman. You may not be able to do this in the trib.
At the US-Canada border (not including the cloudy west coast), they say that solar panels achieve, on an average over a 24-hour period in the winter, the equivalent of one to two hours of sun directly overhead. Using a string of panels capable of providing 1040 watts max at high noon, you'll get 1040 watts for one or two hours (1040 watt-hours to 2080 watt-hours). Theoretically, in that environment, you will be able to run a 1200-watt pump for more than an hour daily, but nothing else. You will become the electricity miser unless you get plenty of solar panels.
I have four batteries dedicated to DC circuits only, which runs the lights and the computer. The power from the other four is run through the converter i.e. converts battery DC to 120 volt AC. I wired the lights with direct DC (even though it costs more for larger wiring) because the inverter uses 100 watts to power a 50-watt laptop, which I use at least eight hours on a daily average. In other words, this big inverter has a dismal 50-percent efficiency rate when providing small wattage. The efficiency rises quickly into the 90s when 200 or more watts are in use at any given time. DC light bulbs cost more, but going DC for lighting is a wise choice for tribulation living, though this causes complications if your place has thin wire.
I'm using LED bulbs at some $15 or even $20 each. They are equivalent to about 25 watts in brightness (as shine the old-fashioned bulbs), but use only three watts. They have a long life, however, to make up a little for their cost. The problem is, I can't get 24-volt bulbs in my area any longer. As 12-volt bulbs are the norm, you can either make your solar system into a 12-volt one (easy to do), or, if you prefer a 24-volt system, you have the option of using it with 12-volt bulbs. But it's "dangerous." That is, you can wire two 12-volt bulbs in series from a 24-volt battery pack so that the two bulbs combined can handle the 24 volts without blowing out a bulb. But when one bulb dies or is damaged by some physical impact, the other will blow out because it can't handle 24 volts. That's what's "dangerous" (i.e. you will be out two bulbs, but there is no fire hazard).
It seems that simply changing the battery system to a 12-volt one is best, yet, as bad fate would have it, the lower the voltage, the larger the wire needed in order to keep the volts from shrinking by the time the electrical flow gets to the bulb. You could probably live with slightly-reduced brightness, but, frankly, I don't know whether there will be sufficient lighting in a bulb socket furthest from the battery pack. If there isn't, you may have a dismal problem.
Your home is likely wired in 14 or 12 gauge wire, but my inspector made me use 10 gauge (larger than 12 or 14) for a 24-volt system. The lower the voltage, the larger the wire diameter needs to be in order minimize voltage loss with distance down the wire. This is why I chose a 24-volt system versus 12. For long runs in the house, I was required to use 10 gauge wire, but this was from the electrical inspector i.e. he wants top-notch in new buildings. A smaller gauge would probably be fine for light bulbs, but long runs with mere 14 gauge could be a problem. It's easy enough to test with whatever wires your house already has. You may need / opt to go with a 48-volt battery-pack system if your home has the smaller 14 gauge.
You can still use 12-volt light bulbs if you purchase a DC to DC converter, converting 48 or 24 volts to 12. If you make the bedroom lights into a DC circuit, for example, the bedroom receptacles will likely be DC too, useless for any AC usage. I haven't looked into it, but there may be inexpensive DC to DC converters that can be installed one per bulb, ideal for making only the bulb into DC; the rest of the circuit remains AC.
You need deep-cycle batteries, not car batteries. Deep-cycle batteries are made to be discharged up to 50 percent their capacity without suffering much damage, and these can last ten years or more (the more they are discharged, the more they age), or upwards of 1000 cycles of discharging from full to 50 percent. If the four batteries cost $1,000, it'll cost roughly one dollar per discharge to 50 percent. How much power do we get for one dollar? Well, I wish it were only one dollar, but we need to include the cost of the rest of the system too. In my system, with new batteries, I get about 5 kwh for one dollar's worth of batteries alone.
Solar batteries are rated in amp-hours, the number of amps the filled batteries can provide, when new, for one hour of usage. Mine are rated at 530 amp-hours, if one full discharge (between 100 and 0 percent) occurs slowly, over 100 hours of use. The shorter the period of full discharge (i.e. the faster the electrical flow), the less total amp-hours we get. So, the Surrette battery company appears to promise that four batteries will provide the equivalent of 530 amps x 24 volts = 12,700 watt-hours over a discharge lasting 100 hours. The battery companies can all be exaggerating a little.
We are directed to discharge only half the battery capacity, meaning that one cycle of discharge gets us about half the 12,700 watt-hours above. From that math, I would guess that 6,000 watt-hours is the maximum, though my gut tells me my new batteries were not raking in that much even while draining the batteries very slowly on a laptop using merely 50 watts DC. To play this on the safe side, let's use 3,000 watt-hours per cycle, on average throughout the battery pack's lifetime. If the battery company promises 1,000 cycles, that's 3,000,000 watt-hours total until the batteries are virtually dead (virtually all the plates have been used up). That's how you should do your math for your particular situation. Figure out your daily need, then multiply by 365, and finally that tells you how many years the one battery pack will last you, or how many batteries you should get.
To find how many watt-hours each appliance / tool uses daily, find the running wattage and multiply by the number of hours that it will run each day. There's a lot of guess work, but it's all you have. If your fridge runs on 200 watts, but runs only 20 minutes (.33 hr) per hour, that's 200 x .33 hr = 66.7 watts-hrs. Every day, that fridge will receive 66.7 x 24 = 1600 watt-hours. For a new battery pack of four batteries like mine, that fridge will take the pack through one cycle every three days, roughly (play it on the conservative side), and, on average (i.e. not a new pack), about every two days. That fridge alone will kill your battery pack after about 5.5 years...if there wasn't any sunlight feeding the fridge directly during the days. That is, if the sun were feeding only the batteries, the fridge would kill the pack after 5.5 years, but with the sun also feeding the fridge, you're going to get more than 5.5 years from the batteries.
How much more? Well, if the sun shines for half the time, I gather that you'd get 11 years. But the sun won't shine sufficiently for half the time, and so drop the lifetime of the pack to about 8 years. If your tribulation endurance lasts only four years, you can run two such fridges on one battery pack. It gives you a rough idea of how many packs you should get, depending on the wattage of your fridge(s) and freezer(s). Then do the same math for your water pump(s), light bulbs, and have some left over for whatever tool work you think you'll need. Some tools take more power than 1040-watt-maximum panels can feed them at the best of sunshine times, meaning that the tools will take some battery power even at those times.
I'm unsure, but, I gather, a run-down or a sulfate-ruined battery pack is not altogether useless. I don't know whether you can run anything on the panels alone (i.e. without batteries installed at all); my understanding is that all electrical end usage (AC) is taken from the batteries, and that all panel power must enter the batteries. Power is said to be "skimmed" off the top of the batteries when the sun shines, suggesting that batteries need to be there. The alternative is to hook panel wires directly to the inverter's wires, but I don't know whether that can be done by a typical, off-grid system. Therefore, even though the batteries no longer take a charge, they can still be useful, I hope, to supply power when the sun is shining. That wouldn't be small potatoes, especially in sunny areas. Use candles at night, fill water tanks, and do all work, by day, though all tools and pumps will need to run with less wattage than the combined wattage capability of all panels combined. Here's Part 2 of a video , showing a battery-bank, off-grid system:
Parts 1 and 3 are immaterial for those wanting to prepare a system off the grid.
Ideally, if money were no object, one would get sufficient panel power to power the biggest, most-important user -- for example the deep-well water pump -- on a cloudy day. A heavy cloud day gets me about 50 watts only from my eight panels. I would need 160 such panels to operate a pump at 1,000 watts. That's too ridiculous, a waste of money that can go to better things. It would be better to stick with far fewer panels, and go without much well water during a string of low-cloud days.
You might purchase a solar system some years before the tribulation, and then take the risk of using the batteries during the tribulation, not knowing how badly they have become deteriorated. Batteries receive less power with age. The battery charger stops charging the batteries when it thinks the batteries are full, and they appear full (to the charger) when ruined. To put it another way: when the batteries can no longer receive power, the charger thinks the batteries are full. Ruined batteries have the most of the surfaces of their plates covered in permanent (unremovable) sulfates that no longer allow electron entry into the plates. Only where there is no permanent sulfate build-up (during discharges) do electrons enter the plates, and once those areas are full, the charger thinks the batteries are full. The less power the battery can absorb when "full," the less you'll have per cycle. It's the same as saying that the battery shrinks in size with age and with bad management.
The good news is that my batteries have lasted nine years. The bad news is I live alone i.e. use little power. In other words, if there were ten people here, I doubt very much that eight batteries would have lasted until now.
During regular charging, the sulfates come off and the plates are cleansed, but, the battery people say, if the sulfates are allowed to remain on the plates too long (long cloudy periods are the culprits), they will no longer come off. This is why it's risky to have batteries linger in the half-charged condition day in and day out. They need to be brought to the fully-charged level fairly regularly, but, the problem is, you never know how many sulfates are remaining on the plates when the batteries are supposedly fully charged.
Therefore, if you undersize your panel power, or oversize your battery pack(s), you could have a kill-battery situation that won't get you the promised number of cycles. If you test a small system at the worst sun-level period of your year, while you're still able to make purchases, you can buy either more panels or more batteries, whichever of the two you still need. That's the best way to get it right. Create a mock tribulation situation at your place starting with a system that you think is too small, and then buy only what more you still need. If you feel that you are in a rush to buy, you can opt to buy plenty of both batteries and panels, because you don't need to use them all. You can always give your spares to others that might need them. As I understand it, thin film can be applied to any substrate; plywood, for example. You can buy extra thin film and leave it uninstalled until needed. For trib purposes, thin-film seems the best way to go.
Batteries die a slow death, even aside from sulfation, because their plates / terminals are thinned by the charge process. When all the metal of a plate / terminal is gone, I don't think a battery can be used in any way. If even one battery dies in that way, the entire pack will not work.
Battery companies have a fix for stubborn sulfation, by charging "hot" at 31 volts (for a 24-volt system) for as long as it takes to burn off the sulfate crust, but if this so-called "equalization" process isn't done often enough, the crust becomes permanent. Follow the manual of your batteries.
Charging at 31 volts produces a lot of hydrogen gas along with oxygen, very explosive. You don't want sparks inside the battery compartment at that time. Make sure all connections to battery terminals are tight, and don't put any pig-tailed wire connections in there connected merely with the screw-on plastic covers. Use the better connectors (or solder your joints) that are more sure to keep the pig-tailed wires together, or, much better yet, do not have any wire-to-wire connection (wire-to-battery only) inside your battery compartment. Really, it's dangerous if the connections become loose, and they could become loose if you're in there moving those wires aside now and then, or changing their hook-up locations from battery pack to battery pack. I use such wires (inside the battery case) to run my DC light bulbs directly from the battery so that I can have bulbs on without use of the inverter.
I don't have a perfectly tight gasket (it's home-made) around the lid of my compartment, which allows some fumes to get through during a charge of 31 volts. The fix was to install a small fan in the 2" exhaust tube that goes between the compartment and the outdoor air; there are safe (sparkless) 2" fans made for this purpose that run on low energy of about 10 watts; they can easily be programmed to run only when good sun is shining (they're not needed turned on during cloud cover). Even though the gasket still leaks a little, the fan probably doesn't allow fumes to escape into my place until the fan shuts off (as soon as a cloud covers the sun, and when I use a lot of power momentarily). Often, when the fan first shuts off, the batteries (they can go on "boiling" a long time after the sun stops shining) are still putting out a lot of fumes through the battery caps, but at least the fan minimizes the fumes into my air space. To be sure that all hydrogen gets out of my small battery room, I have a tube through the ceiling that takes gases out to the attic. It would be safer to take this tube through the roof, but I've been lazy. I figure that small amounts of gas in the attic will find their way out, a good reason to have at least one air vent high up on the roof.
The ceiling of my battery room does not have cracks into the walls, for obvious reason. I have sealed (with caulk) the inside of the compartment so that gases do not enter the walls. Imagine a firefly getting into a wall that's built up with trapped hydrogen. Yikes, is a firefly sparky enough to cause an explosion? I don't want to find out. Be careful, think about what you are doing with your battery compartment and the room that you put it in. Do it right when there will be people living with you.
I haven't been running my fridge and freezer for most of the nights, and may be saving only 15 percent in electricity, but this is not what's important. My freezer operates on about 600 watt-hours daily (equivalent to 600 watts used for one hour), and perhaps 500 watts daily if shut off for 12 hours nightly. The important thing is that more than half of the 500 watts is acquired from the sun, leaving less than half for the batteries. The ideal situation is in summer, when there is sufficient sun for the fridge and freezer to 8 pm, and almost enough to run fully off the sun by 8 am. The first time that the fridge and freezer are turned on, in the morning, is when they run the longest to make up for being turned off all night. The freezer can wait even until 10 am. If no battery power is used to keep the freezer running, it costs 0 cents per kwh of battery use. The less the batteries are used, the less they stand the chance of sulfating (unless you leave them sit in a low-charge state).
Testing with the watt meter (every solar-power monkey must have one), which keeps track of total wattage used on an on-going basis, the 5.5 cubic freezer I have, 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 but in a northern climate). 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 placed in the cold garage as soon as bear season is over. It stays out there until April. It's working for me. The garage door to the house goes into the kitchen, and so the freezer is handy just outside the door. I barely turn it on all deep winter (start of January to end of March). The fridge manufacturer recommended not putting it outdoors in winter, but I've taken my chances over some years. Other freezers may be adversely affected, just a warning.
The freezer manual tells that its thermostat setting should be at about 0 F (-18C). There is a bacteria said to grow in foods from temperatures of about 5-10 F, but if we sufficiently cook food, bacteria will be killed. I haven't gotten any food poisoning with a "warm" freezer. In other words, you can save power by having a warm freezer; just be careful with the food.
The freezer has 1.4 amps and 115 volts on its tag, amounting to 161 watts (multiply the first two numbers to find watts), and yet a watt meter ($25-40) shows that it starts up at 89 watts and eventually comes down to as much as 79 watts after running for a while. It appears that we can't trust those tags at all times. Get yourself a watt meter to know for sure what your appliances run on.
Power tools do not use the same wattage at all times. For example, my 20-amp saw (according to the tag) 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 plywood; and 1,500 watts when cutting 2 x 4s. I've never measured, but you get the point: a tool does not always use the number of amps / watts that its tag specifies. If in the trib your inverter's breaker shuts off while cutting, try cutting slower. If starting the saw shuts the breaker off sometimes, try not shutting the saw off between cuts.
With heat-exchanger tubes (on the back of refrigerators) located in the cold, they will release heat more efficiently, requiring the fridge to operate less time. Plus, the colder the fluid, the better it will absorb heat from the freezer's interior. The potential problem was that the chemical in the tubes may not liquefy when too cold, and may therefore spoil the heat-exchange process. I called Danby's tech department. He said without doubt that cold temperature does not adversely affect the operation of the heat-exchanger tubes. Below is a webpage with this general topic telling that cold temperatures may or may not kill a freezer's / fridge's pump, but then the freezer can be turned off in the coldest periods (at the risk of forgetting to do so). I didn't turn the freezer on until the outdoor temperature climbed above 25 F (-5 C). The motor/pump seems to work immediately well at that temperature, but I've resisted turning it on at colder temperatures.
Both the webpage above and below say that extreme cold kills the freezer's insulation, making the unit require more power in warm months. Is this an online myth put out by electric companies? Some say they have operated freezers in temperatures well below freezing without failures. Where do we find what is rumor verses what's 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 in cool/cold weather. If it holds water, use it as a tank...bonus with its own lid to keep out the flies.
What we can do, if we think it's worthwhile, is to disconnect the heat-exchanger tubes from the back of the fridge. First of all, it's counter-productive when the tubes release heat right beside the fridge. I don't see why one couldn't re-locate the tubes outdoors, or in an unheated space under the floor. I have both options. It would require a few feet of extra tubing to be soldered on, but the fridge repairman can either do it, or tell us how to, and it's going to include replacing at least some of the freon. It's a toss-up on whether this will be worth the expenditure. My freezer, and I assume many newer units, have the heat-exchanger built 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.
I'm being perhaps too detailed, but I'm keeping in mind that you may have this page saved in your computer during the trib, and may need to appeal to some things within it. You may not be able to get online at that time.
Your system will only be able to provide, in AC power, what its inverter can provide. The higher the inverter provision, the higher the inverter cost. My Outback inverter can provide up to 3500 watts at any time. While I never use that much, it's helpful for motor start-ups. Some start-up surges can come near to 3500 watts. If your inverter can't handle your surge, its breaker will trip, meaning you won't be able to use those motors with the breaker too. If you bypass the breaker, you're risking a breakdown in the inverter's sensitive parts (the electronics parts especially).
Ideally, you want to avoid fuses (as alternatives to breakers) in the trib unless you have lots of extras, but where you have motors that challenge the inverter capacity, a time-delay fuse (won't burn out due to temporary / typical motor surge) instead of a breaker makes a lot of sense, at first thought, anyway. My inverter does not come with a built-in breaker, meaning that I install one (between batteries and converter), meaning also that I have the choice of using a time-delay fuse...unless the inverter company says that surges above the inverter's watt rating can damage the unit in some way (maybe not, we hope). For the purpose of overcoming a motor surge (lasts a fraction of a second), a time-delay fuse is equivalent to using no breaker at all. I assume that time-delay fuses have their limits on how much surge they can handle before burning out. Be careful on that; even if the company allows a time-delay fuse, don't oversize one so that it slowly kills a sensitive part of the inverter. The best option may be to stick to a breaker, and just get an inverter that's more than large enough to handle your largest motor.
If two motors start at the same instant, it will trip the breaker, but should do no damage, and won't likely happen twice over a few years. It seems to me that, if the inverter company says its inverter will be safe with two motors starting at the same time (= twice the surge power), and if the company representative is not lying (thinking to self that two motors will never start at the same fraction of a second), then it seems that the inverter should also be able to handle a time-delay fuse (off of one motor). It may be a gamble, and I haven't inquired.
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 (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 could work on the 18 too. However, it's not healthy for the battery pack to do this in a regular / prolonged way, because one or two of the batteries doesn't get used up at all, and this may adversely affect the charging quality of the pack. Inquire if you hope to be able to by-pass the inverter in this way. To alleviate the problem for temporary 12-volt uses, you can alternate from one pair of batteries to the other so that all four batteries are used roughly equally in time. I don't think that any 12-volt usage on two batteries alone on a temporary basis will do any battery harm, but if you're using the batteries this way for nightly light bulbs, then consider using one 12-volt bulb hooked to two batteries and another bulb hooked to the other two batteries, and just make sure the two bulbs are either turned on at the same time, or roughly equal in time if not turned on simultaneously. This would be a good fix if your 24-volt bulbs break down, and all you have left on-hand are 12-volt bulbs. You can have the two bulbs as far apart in the house as you wish. Four another two bulbs, wire exactly the same with the same battery pack, or with a second pack.
It's very useful to by-pass the inverter, especially if just one of its parts burns out and you can't replace it. I use a DC-to-DC converter ($100) to convert my 24-volt batteries (use all four batteries of one pack) to 19.3 volts. With a small adjustment using only a small screwdriver, the unit can convert to anything between about 14 and 23 volts, very handy / useful but not especially cheap. There should be cheaper units. Ideally, you would run a typical electrical wire (2 wires and a ground) from the batteries to a standard wall receptacle, and the unit would be plugged normally into the wall the way you plug anything else in. Be careful not to repeat my mistake of having the DC receptacle beside the AC receptacle (couple of inches away) without a "DC" written on the one receptacle. I twice plugged into the wrong receptacle and fried two such units.
With solar, one needs to become a power miser. To save more energy in a tribulation situation, and to have better security in the meantime, it would be a good idea to wire the fridge and freezer straight from the batteries. I have a small fridge (57" x 24 ") drawing 130-135 watts from the inverter, but the inverter's poor efficiency at this demand level means that the fridge is taking over 200 watts from the batteries (when it's the only electrical thing on at the time). If the inverter is by-passed for both the fridge and freezer, not only would the inverter last longer before failing, but the batteries will last longer too. To run the appliances direct from 24-volt batteries, one would need a device made to convert 24 volts to normal AC power.
The problem may be that the converter's breaker needs to handle the momentary surge from the fridge / freezer motor. I've just called someone to inquire, and he says they don't usually make low-wattage converters to handle a large surge. The page below shows a 24-volt converter to a maximum 700 watts AC for $278 US (Apr 2016). Ouch. If it can handle the surge, that device can run both a fridge and freezer, with much to spare for other things. But is it worth the cost? You decide. One installs such a device at the beginning of the wire (to the fridge and freezer) so that there will be no need to run 24-volt power through the home's wiring. This website has many different converters for all your expected needs:
My fridge is bigger than it looks because it has no freezer box. Although it's only 24 inches wide, it's fridge space is about the equivalent of a typical (with freezer box) 30-inch unit. Opening the fridge door just once (when it's not running) significantly reduces the time to its next start-up. That's because cold air is heavier, which pours out the bottom half of the fridge door while being replaced in the top half by the warm kitchen air. On the other hand, the freezer has the door on top so that all the cold air tends to stay inside when opened. If you're to have a large number of occupants in the house, the energy needed for the fridge will increase significantly. Figure this into your math for sizing your solar system; it could double the fridge's electrical needs.
I don't need the generator all spring and summer long. The message here is that you shouldn't necessary think that you'll be using a generator at all times. 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. Instead of using the generator, I was forced to shutting the fridge down for the winter, and putting the freezer outdoors. It's very doable for trib survival, especially if we'll be eating dried / canned foods. I've use a camping cooler box as my fridge all winter because I've been home all day for the past nine years. I've basically lived a trib situation already, minus the ability to purchase at a grocery store. Whenever I need to get to the "fridge," out I go into the cold garage, several times daily (drives me crazy sometimes). I need to assure that the box comes into the house to warm up so that things don't freeze within it. I've learned to be okay with this. As I edit this chapter here, I have electrical grid power coming in just two days. I wonder what it's like to live normal again.
I purchased an "inverter" generator (Yamaha EF2400IS) that saves gas when it's putting out less electrical power, whereas typical generators (less money) tend to use roughly the same amount of gas regardless of how much electrical power they push. This means that gasoline is saved when charging in the later stages of any one battery-recharge session. Moreover, this Yamaha generator can be converted to run on propane, which I could do for tribulation endurance because propane has a long shelf life. The question is, how much money will be needed to purchase a propane tank(s).
They say that gasoline lasts for about a year before going bad, and that's only if treated with a conditioner. In my first year of owning a generator ($1,000), I didn't treat the gasoline (in the generator tank) over summer, and it started to run improperly. It's never been right since, and would probably have suffered more damage, to the point of inoperable, had I repeated the same neglect a couple of more times. The old gasoline has a negative effect at the carburetor, meaning: be sure not to let aging gasoline sit in the carburetor. Same as with your chain saw, run the generator until it runs out of gas if you know it will be on the same tank of gas for three months or more. It's not enough just to remove the gas from the tank; you need to get it out of the carb. Don't ruin your generator just before the trib arrives; chances are, treated gasoline is good for up to two years, maybe more.
The winters, when the snow covers the panels way up on the roof, is when the generator might be most used. I created an opening through the roof in the middle of the eight panels. There is a place to stand on as soon as I get on the roof. For a wiper / scraper, I have a one-foot 2x4 nailed to the end of an eight-foot 2x4, and because there are four panels on either side of my standing spot, they amount to eight feet long on either side. The 2x4 scraper is long enough to wipe / scrape the snow off the panels. That's what I do, as many as a dozen times per winter. And that's why I don't use much gas for the generator. If you don't provide a way to wipe your panels clear of snow, it would be unwise.
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 that decides (at the flick of a switch) which battery pack gets fed the panel power. Simple enough. Only one set of batteries can be charged at a time...unless an extra charger is installed, in which case one needs to split the full number of solar panels into two separate circuits, one set per charger. With a full household, that second charger could prove invaluable.
You might like to have your solar panels on/near the ground if there are no trees between them and the sun. When not holding regular jobs, we will not be inconvenienced by turning the panels by hand toward the sun in the morning, then turn the panels to face toward the sun at noon, then turn them toward the sun again in late afternoon. To make this easy, have your panels suspended at the top of a steel pole, and arrange a method at the ground (e.g. a steel / concrete socket partway up the pole) for spinning the pole. People who hold jobs daily might purchase an automatic solar tracker, but then it's said that including just one or two more panels gives as much additional power as a solar tracker.
There are two ways to turn the panels toward the sun: 1) as above, by following the sun hourly; 2) by the tilt angle to the sky, whether facing straight up or at an angle, season-by-season.
I came across this: "...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." 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 pretty good. Another chart had shown 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 power by 11-12 percent, while a tilt angle of 60 degrees away from optimum reduced annual energy by 44 percent. If your panels are on the ground, or easily accessible higher up, you can arrange to change their angle to the sky with the changing seasons. I lose a lot of power in summer when the sun crosses directly overhead, for my panels are about 55 degrees off the horizontal (more vertical than horizontal).
Here's some solar-incidence charts:
Propane is the way to go over gasoline for a generator. You can 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 my machine to run on 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.
You run the risk of damaging sensitive equipment when running them off of a generator. My Chinese model generator ruined two computers, but Yamaha claims that its inverter-generator won't harm computers.
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.
I'm not sure whether the writer is fully accurate, but the obvious question: do your solar panels have bypass diodes? 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...
Should we or shouldn't we wire the batteries to a ground rod / plate? One electrical place I called, though not selling solar, said that batteries don't need to be connected to the earth, and yet I can't avoid grounding them to the earth because the panel box (to which the battery cables are connected) needs to be grounded to the earth for the other equipment that it services. I've wondered whether some battery energy leaks to the earth as a result. Here's what one man writes who sounds like he knows what he's talking about:
You don't need to ground batteries. In fact, if you are using an inverter, you better NOT ground your batteries...
...What can happen, is sneak paths develop, and you can trip Ground Fault Protectors - ( AC & DC ) or blow some of the internal protection fuses in inverters.
I don't understand that, but thought I'd pass that along.
My thinking is that lightning is more attracted to the metal frames of solar panels when the frames are more positively charged (the ground is positive), which is why I temporarily disconnect the ground wire (from earth to the panel frames) at the electrical panel when lightning storms approach. In other words, I don't want solar panels acting as lightning rods, and don't want a lightning strike near my ground plate to enter any part of my solar system through the ground wire, wherefore I just disconnect the ground wire (with the turn of a screw) as soon as it enters the house (at the electrical panel). This is an important precaution you can take in the trib, if you think it's wise for your system. If your ground rod/plate is near a buried part of solid rock, lightning, if it strikes the wet solid rock jutting above ground level, could enter the ground wire.
I've read those who opinionate that the panels need to be grounded to earth in case of lightning, but my ground wire from the frames of panels is just 10-gauge, not thick enough to transfer the power from a direct lightning strike. Some insist that the secondary use of the frame's ground wire is for lightning protection, and that 6-gauge wire should be used, but I don't think 6 is large enough, anyway, for a direct strike. The primary purpose: "Grounding the panels is a safety feature to prevent electrical shock in case the wiring touches the frame." I opted to just be careful, and disconnected that ground wire to keep it from reaching the earth.
Some say that lightning rods can be installed higher up on the roof than the solar panels, but even that makes me nervous, as a fork in the lighting can hit a panel once the entire lightning beam has been attracted to the lightning rod. I'm thinking that if the panels are not grounded at all, the panels will simply hide, invisible from lightning. In all my life, lightning has struck the house I was in only once, but you have probably not had even one strike in all your life. Why have a lightning rod to attract lightning? Plus, the size of ground wires recommended for lightning rods in homes is very thick = very expensive:
I do not have a copy of NFPA 780-2004 which explains lightning protection procedures. Hope somebody can answer a few questions. I am connecting a lightning ground rod to a cross on top of a church. The print specifies that the lightning ground wire be run INSIDE the building through emt and that the emt should be spaced 6ft from any other wiring or metal structure. It also says that the ground wire be #1AWG [= size of wire]. Now first of all, I didn't think lightning protection was allowed to be run indoors. Nor does it even sound like a good idea. And the #1AWG seems a bit undersized. Anybody have any input on this? "
I don't use any part of my solar system during lightning storms (i.e. I shut off all power to household items). I shut all breakers down too.
Electricity runs from negative to positive...except in the case of batteries, because when they first assigned positive and negative charges in the pioneer days of batteries, they got it backward. The scientific establishment kept it backward to this day for convenience...meaning that the positive terminal of a battery is really the electrically-charged, or negative, terminal.
If you're like many who loath to purchase arrestors / suppressors (some say they are unnecessary / useless), you may find yourself trusting in circuit breakers and fuses for trib insurance. When lightning arrestors are being discussed by solar-power people, the primary danger may be from electric-grid wires in the area (because many people on solar are also on the electric grid), but in the trib we can disconnect from the grid. Having two circuit breakers / fuses in any electrical line may act as an effective "lightning arrestor" (so long as you shut the breakers off in a storm). If the lightning power jumps the first breaker's gap, then hopefully, there won't be enough to jump the second breaker's gap.
Here's an article on battery charging.
As you can see on a sun-hour map below, 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.
http://sunelec.com/index.php?main_page=page_2 (map seems to be removed from this page)
There's a global sun-hour map at http://lreese911.tripod.com/sitebuildercontent/sitebuilderfiles/solorpower.pdf