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Going Off-Grid #170599
06/12/2019 10:44 AM
06/12/2019 10:44 AM
Joined: Oct 2001
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Going Off-Grid w/ Solar, Part 1: An Overview

https://mountainguerrilla.wordpress...rid-w-solar-part-1-an-overview/#comments
June 10, 2019

Talking about solar power and off-grid utilities is a sketchy subject, even amongst people who advocate for “self-reliance,” and “liberty.” It can stoke people’s anger, very, very quickly, I’ve found. I’m not exactly sure why that is, but I suspect it’s primarily three things.

First is, it smells like patchouli and unwashed hippies. After all, it’s “green” energy, right? I mean, it’s actually not, really, but, it is often marketed that way (we’ll come back to why it actually isn’t later). And, if you’re “green,” you’re obviously a nasty-smelling, foul leftist. Everyone who is a real conservative knows that we have enough coal and oil in the United States to keep our economy going for the next 500 years, without problem (well, except for the folks in the oil industry that actually understand how oil industry economics actually work, but again, that’s irrelevant to the current conversation).

The second issue about off-grid alternative energy is, it can’t save everyone. Alternative energy production, whether wind or solar, doesn’t pencil out well, at all, on the industrial scale. It works best on the small-scale, at the individual home, and—arguably—the small village. It doesn’t work worth a shit on the city, county, state, or national level. Many people, even in the “liberty” oriented “self-reliance” communities, seem to get really pissed when someone else finds a solution that allows them to live with some semblance of modern civility and utilities, even when a storm knocks out the local power (granted, my tendency, when someone announces that the power is out, to respond with, “Really? Weird, mine isn’t.” probably doesn’t help their anger management issue…).

Finally, and I suspect this is the biggest part, even though it’s actually the easiest to remedy, is the apparent cost of alternative energy installation. There are hundreds—if not thousands—of books available, dedicated to alternative energy. There are books on system design. There are books on component selection. There are books on installation. I’ve been reading books on alternative energy for well over 20 years, and I’ve barely scratched the surface. There are thousands—probably millions—of magazine articles, website articles, and even entire websites, dedicated to alternative energy systems, covering the same array of information.

Unfortunately, one the things I’ve noticed about the media available on alternative energy is, almost exclusively, it tends to tell people how expensive alternative energy is. I’ve seen books and magazine articles, in recent months, that insist a household PV system (PV stands for Photovoltaic, the proper term for the method solar panels use to produce electrical current) will start at a minimum of $10,000. I’ve talked to people who have had PV systems installed on their homes, and they invariably have paid closer to $20,000, and those were grid-tied systems.

In our local area, there are two or three different companies that advertise locally about their solar installation services. “Cut your electric bill to nothing!” “When was the last time you had a $15 electric bill?” (The basic hook-up maintenance fee in the local area is right at $15.).

I have a cousin who used one of their services, and had their entire roof retrofitted with solar panels, in a grid-tie system, hoping to reduce their electric bill dramatically (it’s the South. It’s hotter than three feet up Satan’s asshole here, in the summer). They did. He was stoked, when he got his first electric bill, and it was $22, when it had been almost $200 the month before. On the other hand, when I asked him what his monthly payment on the PV system was, and he said $400, he got a really crestfallen look on his face, when I started laughing my ass off at him. I don’t know how long the note is, and I don’t know what the interest rate is, but in his case, solar doesn’t win, especially since, if the power goes out…his goes out too. The utility companies generally don’t allow grid-tied systems to have battery bank support, because then, if the power goes out, your system is still charged, and could—theoretically—backfeed into the system, and kill one of their linemen.

So, grid-tied solar definitely does not pencil out, at the current time. Even though it’s sometimes marketed as being “more environmental,” because it “reduces the amount of fossil fuels the power company has to burn,” this is simply untrue. The power company has to keep the generators running, because they don’t know when a whole bunch of people are going to suddenly turn on their air conditioners or video consoles, and they’re going to need a very sudden upsurge in power. It certainly doesn’t pencil out for affordability and savings for the home-owner. Even if you paid cash for the system, it’s going to take you decades to get your investment back on electric bill savings.

Well, then why use solar?

————————————————————————————————————–

We chose an off-grid solar system for power for a couple of reasons. First of all, when it’s done right, it can actually be extremely affordable. For a rural location like ours, where the power company was going to have to install new poles and lines to reach our house, the cost of our PV system was dramatically less than what the power company wanted for the installation, and we don’t have ongoing electric bills on top of it. I’m kind of a cheap fucker. If I’m going to spend money, I want to spend it on things tangibles.

Second, we wanted reliable power. While our local utility is actually pretty decent, there have been a half-dozen outages in 2019 alone. We’ve had one, from a nearby lightning strike causing the breaker in our system to pop. While it took the utility company between 12 and 72 hours to get all the power back on, it took me 30 seconds to walk over and flip the breaker back on.

Third, we wanted resilience. Regardless of your position on Peak Oil, and other issues, the reality is, if the economy collapses—as it is showing increasing signs of doing, according to a wide range of economists with pretty solid track records, the power company isn’t going to make keeping power on to residences a priority. In the event of a CME or an EMP—both of which even the government is increasingly admitted are a matter of when, not if—the power company is going to be toast. Will a small-scale solar installation survive? Maybe, maybe not, but it damned sure has a better chance than the large utilities.

For all three of these reasons, a grid-tied system simply didn’t make sense for us.

I managed to build our system for less than $3000. It started out, when we were living in a portable shed, and building the house, with a single 210W, 12V solar panel, a cheap inverter off Amazon, three Marine/RV batteries from Wal-Mart that combined offered 330 amp hours of power, and a 700W inverted from the local parts store. The batteries were $70 each ($210). The solar panels was $105. The inverter was about $34, and the inverter was $70. We used that system for two years. At a total price of $429 (let’s round it to $450, to cover the cost of the wires and different connections I used), amortized over the 24 months we used it (I think we actually used it for 26 months, but…), our “monthly electric bill” was $17.49…the house we rented before, our monthly bill was $120 a month. So, in four months, we had broken even, and the rest was—literally—free energy, at that point.

Of course, that small of a system limited what we could run on electricity, if we didn’t want to kill the system of run out of power. In that shed, we had electric lights (and with babies in the house, we generally leave at least one light on through the night), two fans running through the day, in summer, and a smaller, 36” flat screen television and DVD player. We also charged laptops and cellphones. There were only 3-4 days, in that time frame, when I had to tell everyone to turn everything off, except the lights, because the batteries were low. In every one of those cases, I was able to hook my truck up to the battery bank, with a pair of jumper cables, and recharge the batteries, in an hour or so.

Our current system is significantly larger, but still smaller than most off-grid PV systems. We have six 240W panels, making our PV array a 1.4KW array. Most household sized units that I’ve seen are closer to 5-10KW. We have a 60amp SunnySky MPPT charge controller, an AIM 5KW inverter, and twelve 105ah Duracell AGM batteries, for a total storage capacity of 15.75KWH (105ah x 12.5V x12). Of course, since you don’t actually want to discharge the batteries past 50% capacity, really, we’re limited to roughly 7.5KWh of capacity.

The panels were purchased for something like $120/panel, for a cost of $0.50 per watt, which is, of course, significantly less expensive than the roughly $3.00 per watt of a retail price. The panels were new in the box, located via a Craigslist ad, by a friend (full disclosure: even though I was going to repay him for the cost of the panels, he ended up giving us the panels, so I actually didn’t pay for them. I’ve still included the cost of the panels in my overall cost estimates). They are manufactured by Trina Solar.

The charge controller, from SunnySky, was purchased after my previous charge controller, purchased via Amazon, for $50, turned out to not be a MPPT controller after all, and caught on fire one day, when the panels were producing more power than it could handle. Nothing better than smelling burning plastic, and looking frantically for what the source is, only to see your charge controller, right next to a bank of batteries, in flames! The SunnySky charge controller cost me something like $200, and has worked amazingly well for two years now, and has a much easier to read and understand digital display than the other piece of shit I had. The AIM inverter, even for the 5KW version, was only $400. That’s a total, so far, of $1320.

The battery bank was, by far, the single most expensive aspect of the system. After using a set of cheap Everlast Deep Cycle Marine/RV batteries for three years, including a couple of ill-advised deep discharges, we had two of the three batteries go bad. One was completely dead. It wouldn’t hold a charge over 11.2V. The other would hold a charge, but only at 12V, meaning it has lost half of its capacity (a fully, 100% charged 12V battery should actually be at 12.5-12.6V).

I contacted the local off-grid solar installer, and asked him for the price of an on-site consult. It turned out—unremarkably, given the local culture—that not only did we have a couple of mutual friends, he had actually heard of me, and was interested in looking at my system anyway. He came out, looked over the system, and declared it “good to go. I wouldn’t have done it any different, except…” he recommended a couple changes I already knew needed to be made, like getting my wiring from the battery bank to the house, either buried, or up off the ground, and that I needed to build a better structure to house my battery bank. For the record, both still need to happen…

I asked for a recommendation on higher quality batteries. Expecting him to recommend really expensive golf cart or forklift 6V batteries, I was pleasantly surprised to discover that he recommended—and used on his installs, unless the client specified something else—a simple 105ah glass mat battery by Duracell, that was available from Sam’s Club. I checked Sam’s Club, and the batteries were $179 each, plus a core charge of $10, for a total of $190. I have twelve batteries in the bank, currently. Total cost of the batteries was $2280, but I didn’t—be sure—buy them all at once. I started with four batteries, and then added two every two months, until I had ten. We used just ten for the better part of a year, before I finally went and bought two more.

So, thus far—including the cost of the panels, we’re sitting on $3600 worth of PV system. Of course, when you add in incidentals like wiring and connectors to put the system together, it’s probably closer to $3700.

That’s considerably less than the $5000 the power company wanted to extend the lines to our house, and I don’t have electric bills. For me, that was a no-brainer. We currently manage to run a 7.5 cubic foot deep freeze, lights throughout the house, a radio, the large flat screen television, a DVD player, three or four fans throughout the house in the summer, and we charge two cellphones, two laptops, four two-way radios, a shortwave radio receiver, and a few other things that escape me at the moment.

We have been using the current power system for pushing three years now. Amortized over the course of 36 months, our power “bill” comes out to $102. That’s not particularly impressive, until you start looking at the longevity of PV systems. It is currently expected that PV panels SHOULD have a working life span of 20-30 years, before there is a noticeable drop in power. Assuming we can get the expected 7-10 years of life out of the AGM batteries, versus the cheaper Everlasts that lasted three years, and absent a lightning strike that blows up the inverter or charge controller, we should get a solid four more years out of this system, without needing to spend more money on it, and probably more like another seven years. If we get the low end of seven years of life out of the batteries, we’re looking at a cost amortization of $44/month. If we get the full ten years, it drops to $30 a month.

It’s important to note that, while the AGM batteries don’t require maintenance, I do check the batteries monthly, with a voltmeter. Even after the amount of time we’ve been using this set of batteries, our batteries are still at 100%. We’re extremely careful to make sure we don’t get them below a 50% depth of discharge though. I’ve heard of people getting 15 years out of a set of batteries. While I don’t expect that, it would make me very, very happy.

Talking to friends in town, the average monthly power bill these days, in our area, is just north of $200/month. While the cost savings are nice, the bigger benefit on that front, from my perspective is, the system is already paid for. I don’t have to worry about making that bill every month.

More important to me, is the independence it offers me. One of our neighbors works for the county water department. Since we use rainwater catchment for our primary water supply, and have a composting toilet, and a greywater system, we don’t use the county water system. I was talking to that neighbor the other day though, and he mentioned that, at some point, I should expect that someone from the county was going to show up at our gate, wanting to inspect the property, for tax appraisal purposes. As he pointed out, they’ll see the place on satellite imagery. (To be clear, he’s 100% supportive of what we’re doing…and when I pointed out that if it was the Water Department that showed up, I’d know exactly who sent them, he hastened to tell me it wouldn’t be him, because he didn’t want to end up dead).

I responded that, there’s no building inspection/code enforcement in the county, so what were they going to, besides appraise it for taxes? He thought about it for a moment, and laughed. “Yeah, usually they threaten to have your power turned off, because you don’t have county water hooked up. That’s not going to work with you, is it?”

Nope.

Creating our own power offers a lot of independence. Developing our own water sources (we could do a well, but while local hand dug wells usually hit water at 10-15 feet, most of the drilled wells in the area are closer to 2000’, and we’re on top of the mountain, so it might even be deeper…and that shit is expensive!), with three spring-fed ponds for back-up (our water catchment system cost me less than $500 to build, and currently holds just over 1100 gallons), increases our independence. Local monthly water bills in the county are currently running approximately $105/month, so there’s financial savings on that front as well.

Finally, we get a lot more resilience out of our system than the local utility subscribers do. Our closest neighbor is ¼ mile from us, through the woods and across a pasture. Their power goes off for at least a couple hours, every time a storm blows in (and since we’re on top of the mountain, a LOT of storms blow in, at full strength), from downed lines. They are at the end of the power line, so they are hardly a priority for repair. As I mentioned previously, our power has gone out once this year, and it was a thirty second, effortless repair for me.

If the power grids go down for a longer term, our system will not last forever, of course. Batteries go bad eventually, electronic components short out or burn out. Solar panels can catch hail stones or thrown rocks, or other flying debris, and crack or break (PV panels are actually remarkably resilient though. Ours has absorbed golf-ball sized hail with no damage at all, even when metal roofs were dinged to Hell.)

But, our system does offer a more cushioned fall. We will be able to run lights a lot longer than others will. We will be able to keep our chest freezer running longer, facilitating much easier food preservation. We will have entertainment options for the children, beyond just doing chores and homeschool work.

Sure, a gas, diesel, or propane generator would allow us to do that as well, but not for nearly as long. Sure, batteries die, and while standard truck or car batteries are not particularly convenient for off-grid power applications, they will work in the short-term, and there will be a LOT of unused car batteries available, when nobody can get fuel for their cars. Even if an ad hoc battery bank like that only lasts six months or a year, with enough salvaged batteries, that gives the system a really long lifespan, even if the Duracell batteries don’t make the 10 year expected lifespan.

————————————————————————

We’ve been using a 5KW gas generator to to run power tools. Obviously this is not as sustainable or resilient as it could be. One of the fixes I have found is to begin switching as many tools as possible over to battery-powered tools. I was really hesitant to do this, initially, because of bad experiences in the past with battery powered tools, but I started with a couple of DeWalt cordless drills, and pretty soon found I also had a DeWalt cordless circular saw, and then a cordless Sawz-All, etc. I’ve not switched over completely yet (DeWalt doesn’t make a cordless angle grinder, that I’ve seen, and all of our power tools are DeWalt, except for a single Milwaukee hammer drill, and one Milwaukee circular saw that I’ve owned for twenty years.) I’ve been using the cordless tools an increasing amount, over the last two years, and have fallen in love with them. While I used my standard DeWalt circular saw for most of the work building our house, I don’t think I’ve pulled it out a half-dozen times since, for various projects, reaching for the cordless saw instead.

The battery pack tools are convenient, because I can charge them off the household electrical system quickly and easily, if not efficiently (think about it…the solar panels are charging batteries, which provide power to the house…which is being used to charge batteries. A better system would be to hook a PV panel directly to the batteries to charge them somehow. Unfortunately, I’m not smart enough to figure out how to do that….

—————————————————————————

There are a number of things I’ve done “wrong” in developing our off-grid solar power system, according to the prevailing wisdom. Most obvious is, “don’t mix old batteries and new batteries.” Well, that’s fine, if you can pony up the money for all your batteries at once, or if you never have to expand the system’s storage capacity, but for the rest of us, it’s kind of a necessity. What I’ve found seems to work though is to simply check the status of the older batteries, before adding a new battery. If your old batteries are still capable of 95% or more of their new capacity, you’re probably okay adding new batteries to the bank, without worrying that it’s going to kill your new batteries.

I “fucked up” by purchasing “cheap” components, like the inverter and charge controller, that were Made in China. As I mention in the new Rifle book (shipping starts next week, for those who have pre-ordered, see the “Campfire Chat” article for this week), I see a lot of people who seem to use their rifle accessories as status symbols. “Oh, I’d never buy anything less than a US Optics/Scmidt & Bender for my rifle! Anything less is Made in China crap!” Never mind the fact that the photo they show of their rifle makes it abundantly clear the rifle is not used for regular, realistic training, but is a much-beloved safe queen. I see the same thing happening in solar discussions. “Oh, if you don’t spend at least $3000 on your Trace Inverter, you’re going to hate it, and your house will burn down.

Do you get what you pay for? Within reason, generally yes. Sure, a Trace Pure Sine Wave inverter would probably produce a slightly better form of electrical current than the AIMS modified Sine Wave inverter I have. Is the difference worth $2600? I don’t know, but it’s not to me. We manage to run a lot of electronics, on our modified sine wave electricity, that the conventional wisdom says we shouldn’t be able to, with no problems. I’d rather spend that $2600 on something else. Fortunately, I live in a place where off-grid living still generally means “no electricity or running water,” so even having a solar system is unique enough that I don’t need to “brag” about it. I don’t need to use my PV array as a status symbol. Hell, I built my house by hand, using traditional building methods. That’s bragging rights enough, as far as my neighbors seem to be concerned (we’ve had neighbors we don’t know, show up asking if they can check out the house, because they heard about it from someone).

I am going to expand the system. I have several more of the Trina Solar panels in storage under the house. My plan is to build a second, slightly smaller system, independent of the house system. I will put the freezer on the second system, and add a ductless “mini split” air conditioner to the house. A 24,000 BTU system can be found for around $1000 brand new, and I’ve got a local friend who got his used for less than $500. The cool thing about the mini-split is that they use considerably less power than a standard A/C, and the start up for the compressor is capacitated somehow, so it’s not a sudden surge that kills the batteries and overstresses the system. My family—and myself—will be grateful for the cool air, in another month, when night time temperatures are in the upper 80s, and humidity is at 90%.

The best part of switching the freezer to the new system will be the ability to put a regular refrigerator on the current system. We’ve been using a propane refrigerator for a couple of years now, because everything I had read claimed they were super efficient, and the most economical way to run a refrigerator off-grid. Unfortunately, they actually blow through a LOT of propane, and the local propane company won’t deliver to our house, because of the access road condition.

So, since we can’t get a 500 or 1000 gallon tank filled, we use several 100# tanks to fuel the cookstove in the kitchen, and 20# tanks to fuel the refrigerator. Our refrigerator—a deluxe side-by-side model from a RV—is reputed to be one of the better versions, but it only gets about 8 days out of a 20# tank of propane. I can currently refill a 20# propane tank for around $15, but when I have to do that four times a month, that starts adding up in a hurry. It would be more economical, as far as I can tell, to add a couple of panels to the array, pushing it up to a 2KW system, and a couple more batteries, and just use a regular electric refrigerator. Considering I can buy a used high-efficiency base model refrigerator for a couple of hundred dollars, and the propane fridge cost me $1300—and an eight hour round trip drive—it ends up penciling out better to just run the electric fridge, after expanding the current system. Now, if I could just convince someone to buy the propane fridge off me…..

A lot of solar “experts” insist that, for a household sized system, running a 12v system is uneconomical. They all recommend stepping up to a 24 or 48 volt system. We started out with the 12v system, because we were running such as small system. While I might get some more economy out of the 24 or 48v system, I can’t complain about the 12v system, and I already had the components. I may try 24 or 48V for the secondary system, for the freezer and A/C, but I really haven’t decided yet.

—————————————————————————–

Ultimately, I highly recommend going off-grid solar, if you live in a rural environment that makes it plausible. You’re probably not going to get to install and use an off-grid PV system in the middle of a city or a subdivision. In that case, I think a PV generator, with a single panel or two, and a couple of deep cycle batteries, that will keep your essentials running for a while, in the case of a mid-term power outage is a really solid idea. To me, it makes far more sense than a loud diesel or gas generator. Especially in a situation like a Hurricane Katrina situation, where you might want to keep stuff running in your house, without enticing looters, the silence of the solar generator offers some significant advantages.

Designing a PV system can really be accomplished two ways. The first—textbook—method, is to conduct an energy audit of what your current electric uses are, and then build a system to suit that, possibly with some oversize percentage built in, in case you need it later. This is also the most expensive way to design the system, outside of simply paying an outside contractor to come in and do it for you.

This method wouldn’t work for us, because we didn’t know what our usage was going to be. We knew we were giving up a lot of modern electronics—well, we thought we were—to go off-grid, and so we weren’t able to determine any sort of accurate figure.

We used what I call the “ol’ broke hippy” method of designing the system. We bought what we could afford, when we could afford it. When we had enough to cobble a small system together, we did. We used that, until we determined we needed to expand the system, then we added what we needed to get the desired expansion. This allowed us to take our time purchasing components, looking for the best prices and best components. There is a great book, available from Real Goods Solar, called “The New Independent Home,” by Michael Potts. It’s a series of case studies, from the 1970s-1990s, of folks who built off-the-grid houses and homesteads, using different methods and approaches. I read the original edition of the book in the late 1990s, when I was in the Army, and loved it. The newest edition adds the “New” to the title, and is even better. Be forewarned though, most of the people he discusses are very….well….”earthy” would be a good way to describe it…. (Books are the only thing I’ve ever actually bought from Real Goods, strangely. They offer a lot of really cool off-grid stuff…)


"The time for war has not yet come, but it will come and that soon, and when it does come, my advice is to draw the sword and throw away the scabbard." Gen. T.J. Jackson, March 1861
Re: Going Off-Grid [Re: ConSigCor] #170606
06/12/2019 11:11 PM
06/12/2019 11:11 PM
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Good article.


Training to be the best I hope I never have to be
Re: Going Off-Grid [Re: ConSigCor] #170811
07/08/2019 10:28 AM
07/08/2019 10:28 AM
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Sizing Solar

By Mountain Guerilla

Entirely too often, when we start talking with the average “prepper” type, with their focus on some potential future singularity that will result in SHTF or TEOTWAWKI, we see an emphasis on trying to maintain the status quo as much as possible. This ranges from “I’m gonna stockpile enough fuel to run my BugOut Vehicle, because walking is for plebes” to “I need a 18.9 KWH stand-alone off-grid power system with PV panels and an automatic switchover diesel/propane/etc generator, because I want to run the same six televisions, four video game consoles, eighteen laptops and assorted other electronic devices, and I want to be able to leave the lights on all the time if I want.”

This is a ridiculous notion of course, and even though too many “preppers” unconsciously adhere to it, they still generally have the sense to at least verbalize, “Man, SHTF is gonna be rough,” even as they imagine themselves not suffering too much. The more I’ve studied and discussed things with experts in other areas, the more the concept of “Collapse Now and Avoid the Rush” has made sense to me. By reducing our supposed needs now, we enjoy two benefits: first, we begin to recognize how little we actually need, and thus, how much of our purchasing is a matter of being convinced by marketing that we “need” or “want” shit that we really don’t have any use for.

Doubt it? Look at the growth industry known as “self-storage.” The idea that you have so much shit that you don’t use daily, that you need a separate, off-site place to store it, is mind-boggling to me. I’ve rented self-storage units before, but only in the short term, while in the process of moving, or—in the case of the farm—while building the house.

Specifically today, we’re addressing the electrical demands of “off-grid” living during the decline. Typically, when I’ve looked at either installed package deals for off-grid PV/Solar, or I’ve read the descriptions in various books and magazine and web articles, there is this assumed notion that the purchaser is going to run what might be termed a “modern” household on the system. Of course, this includes not only lights, refrigeration, television and DVD, but also the requisite Amazon “Alexa” device, gaming consoles and Internet routers, food blenders and processors, microwave ovens, and a host of other things that I’m sure I’m overlooking, since don’t use any of it, let alone rely on it.

When people find out I’ve spent so little on building our PV system, they usually respond initially with “bullshit!” but then they want to know how I managed it.

There are two basic ways to determine how big of a system you need. The industry method is to determine what you typical daily usage is, factor in some marginal amount (10% for instance), and then multiply that by 3, in case of cloudy days or inclement weather, and then build your system around that demand.

In order to do this, you simply need to know the wattage of every electronic device you will use on the system. Some devices this is easy to determine, because it is listed on the packaging. Light bulbs for instance, almost invariably tell you exactly what their usage is.

For other items, like fans, or televisions, this requires a little bit of math. Fortunately, that math is pretty simple. If you look at the UL label on the back or side of various electric appliances and devices, it will generally tell you what the voltage is, and what the amperage draw is. By multiplying these together, you get to figure out the wattage. As an example, our bedroom fan (we don’t have A/C in the house yet), draws 0.6 amps, at 110 volts. So, 66 watts, assuming I just did my math right… Our television, on the other hand, also uses 110 volts, but draws 5 amps, so it is running 550 watts. By adding up the wattage of all of your electrical demands, you can determine what your total daily consumption should be. Then, you multiply that by a given modifier, representing a number of days, to account for the maximum expected days you might have total cloud cover, negating the panels’ ability to recharge the battery bank. It’s really pretty simple.

The problem with this, for us, was that we didn’t have any idea what our total demands might be. I might go all week without using my laptop at all, and then be on it most of the day on Sunday, prepping my articles for the blog for Monday. At other times, I might spend 5-6 hours every single day, for several months, working on a book. My kids don’t generally watch more than 30-60 minutes per day of cartoons on the DVD, but on a shitty weather day, we might let them watch a couple of movies, adding up to 3-4 hours. My wife goes through phases where she won’t watch a movie for weeks, and then she’ll go through a phase where she stays up late, watching movies until 1 or 2 in the morning, while I lay in bed reading.

Of course, that is daily life now, rather than in a post-grid environment, where we don’t have time for recreation, right? Well, not exactly. You’ve got to remember, after all, that we live this way every day. It’s not a summer vacation for us. We take care of the animals and the gardens every day, just like we will when things get worse. I spend time in the gym and on the range every day, just like we will when things get worse (We have a pretty decent Crossfit box in the backyard, as well as cross-country sprint interval tracks cleared and measured for 200, 400, 800, 1000, and 1600 yards. Anything longer than that, I map out a cross-country route, or just run the roads). The only thing that will really change much, in our daily scheduling, as things get worse, is we can reliably expect to have more people around, as various members of the clan decide it is time for them to emigrate to the farm from their homes in town. So, there might be slightly less television time for the kids, since they can be sent to play with their friends and cousins, more often than the 2-3 days per week they currently get to spend with our people.

There will be slightly less light usage, since I’m more likely to be outside after dark, providing security efforts, but even then, that will be balanced out by the demands of recharging batteries for night vision, flashlights, and etc….

(Which, in itself, is a great example of re-thinking traditional prepper concepts. When I was growing up, the conventional preparedness wisdom was, have lots of kerosene and/or white gas Coleman lanterns to see by after dark. For Night Vision, you still have people who seem convinced that “ten minutes after the lights go out, all the battery-powered equipment will be useless. My question becomes, which do you think is going to run out quicker? The amount of kerosene and white gas you can safely store in your home/garage/outbuilding/etc, or a handful of quality rechargeable lithium batteries for aircraft aluminum flashlights and battery powered lanterns? Take your time thinking about it. It took me a good decade to realize my older conviction on the matter was inherently flawed…)

Additionally, we had limited funds when we were building (we still do, to be sure!), and a lot of the appliances we already owned were not at all appropriate for an off-grid PV system. So, rather than sit down and try to pencil in hypotheticals, I sat down and determined what our absolute minimum “must-have” was, to keep my wife and kids from mutiny. Then, I looked at what I could afford to do. I realized I could probably do the above, with three days worth of reserve, based on the needs I had listed. Those boiled down to, “low wattage demand lights in each room, the ability to charge two cell phones, and two laptops, as well as the ability to run the television and DVD player, and a chest freezer (which I will come back to…).

Once I knew the wattage demands, I needed to convert those to watt-hours. To do that, you simply multiply the watt demands by the number of hours you expect each device to be used daily. So, if my television draws a hypothetical 500 watts, and it is turned on for 6 hours a day, that is 3000 watt hours, or 3 kilowatt hours (KWH). If I keep the lamp in the living room area on from around 9PM, when I go to bed, until 7AM, when I’ve finished getting out of bed, doing PT, and eating breakfast, then it is on for 10 hours a day. If the bulb draws 9 watts (it does), then I’ve used 90 watt-hours.

So, based on my total KWH usage, I can determine both the wattage of my panels needed, and the battery bank storage I need (and, in fact, to a lesser degree of importance, the size of the inverter I need. Lesser, because I simply oversized that to a 5KW inverter, so I knew I would have ample leftover load availability).

We’re far enough South that, even in the winter, most days, we’re going to get a solid 8-10 hours of sunlight on the panels. I have a 1.5KW panel array currently that, according to my charge controller, which is a 60 amp controller, produces around 58-59 amps, for 6+ hours a day, even in winter time. That means, my panels are producing more than 9KW per day. Really, they’re producing closer to 12KW, according to my half-assed record keeping efforts. Of course, that’s on sunny days. On overcast days, they produce less. I will say though, that, unless we are socked in with rain or fog, even on completely cloudy days, we’re producing at least 40-50% of those numbers.

Our usage at night is low enough that, usually by 9AM, my batteries are back at 100%, and are in a float and equalization phase, maintaining their life span.

Our battery bank started out with 6 Everlast Marine/RV deep cycle batteries from Wal-Mart. Those batteries, that no serious off-grid solar person would look seriously at, cost me $70 each. They lasted the better part of three years (and some of them are still in use in different applications). When I replaced the battery bank, I wanted something better, but I knew I couldn’t afford to buy forklift batteries or any of the other typical high end off-grid battery choices. On the recommendation of a local acquaintance who specializes in off-grid installs, I went with Duracell AGM batteries from Sam’s Club, for $170 each. Initially, I bought six of them, each of which is a nominal 105 amp hours. Multiplied by the 12.6 volts of a fully-charged 12V battery (don’t ask, because I can’t explain why the fuck a battery is called a 12V, if a 100% charge is actually 12.6 volts….), that ends up providing just short of 8KWH of storage. Of course, if you discharge below 50%, you dramatically reduce the life cycle of the batteries, so functionally, that battery bank provided a mere 4KWH of storage. In theory, that should not have been enough, since it didn’t offer any leeway for cloudy days without sun. In practice though, we found that it did. All we had to do was, on days without clouds, the kids weren’t allowed to watch anything on DVD until after the batteries had reached 100%. Since we get some charge from the panels even on cloudy days, this really ended up not making any difference in their lives at all.

Nevertheless, in the interest of keeping the system more robust, I eventually added more batteries, as I was able. This is generally frowned on in the solar world, because if one of your older batteries is weakened, it will draw down and damage the brand new batteries. What I’ve found has worked well for me is to simply make sure I tear the whole battery bank down, and test each individual battery, before adding the new batteries to the mix. So far, this has worked well for a couple of years anyway, and I don’t foresee any sort of reason why it shouldn’t continue in the future. What I have ended up with thus far is 12 of the Duracell batteries. That’s a nominal capacity of 15.8KWH, or a practical limit of 7-8KWH. My 1.5KW array, as I mentioned previously, tops that off by 9AM, even in the winter.

For us, that means that, since the panels then maintain the battery bank at a float charge of 13.75 watts, until late in the evening (around 7:30PM this time of year, and—conveniently—because of latitude, roughly the same most of the winter as well), when the house shadow finally blocks the sun from hitting the panels, we can use all the electricity we want, with no concerns.

Assuming you paid the $1/watt for panels, the panel array could be put together for $1500. The battery bank cost me $2200 (I had to pay core charge on a couple of the batteries). My inverter was $500. My charge controller was around $300. So, for less than $5K, I’ve got a system that I barely put a dent in the maximum capacity of.

How did I do that? By reducing our demand. We collapsed now, and avoided the rush.

What do we have, in our house that runs off the electrical system?

A 54 inch flatscreen television. It’s not connected to anything except the DVD player, and occasionally my wife’s laptop when she downloads a movie to watch.

A small DVD player. Seriously. It was like $30 at Wal-Mart like 4 years ago.

7-9 watt light bulbs, throughout the house. Off the top of my head, we have 10-11 in the house. At any given time, somewhere between 2 and 5 of them will be turned on. We’ve conditioned the kids to understand that they have to turn lights off when they leave a room, and they know they are not allowed to sleep with the light on.

We have four fans in the house. Three are box fans that draw 0.6-0.8 amps. One is a small reciprocating fan in our bedroom area that draws 0.4 amps. For further air conditioning, we installed a “geothermal” system that involves 100 linear feet of 4” pipe, buried 6 feet below the surface, and coming up through the floor in two different places. It works…..meh. Between it and keeping windows open, it will keep the house 20 degrees cooler than the outside temperature. That’s significant…until the outside temperature is 120F…..

We charge two laptops (occasionally. My laptop usually gets plugged in on Sunday morning, so I can write my articles for the week. If I’m working on a book, I do it during daylight hours, and then unplug the laptop for the night). We charge two cellphones, and most of the time, I forget to plug mine in until I get in the truck to go somewhere.

I run a Ninja blender daily. It’s actually got a pretty high draw, but it’s only on for literally seconds, so it really doesn’t even count, as far as I can tell. Beyond that, we’ve got Streamlight rechargeable batteries for flashlights, Yaesu radios on chargers, a couple of cheap Cobra handy-talky radios on chargers, and a AA/AAA charger with rechargeables that gets plugged in when I need to charge some.

The only other thing currently on our system is a 7 cubic foot chest freezer. It draws a pretty significant amount (I want to say like 500 watts?) when it is running, but it only runs a couple hours a day, even in summer, so it’s not that bad. The big issue with the chest freezer is the same issue with running power tools and refrigerators off inverters, and that is the start-up surge. Typically, we tell people to budget for 2-3x the running draw for the start-up surge. It doesn’t hurt the battery bank or the solar panels, since it only lasts for a second or two. What it is rough on though is your inverter. We weren’t able to run the freezer on our first inverter. That was a 2KW inverter, but it was purchased at the local AutoZone, and is used by plugging cords directly into it. The problem with them is that none of the outlets will actually tolerate a 2KW draw. Each is only good for 500 or so watts. My 5KW inverter was fine with the load, unless I turned on everything in the house at the same time.

The current 3KW inverter that I purchased to replace the 5KW one, after it was damaged by lightning a couple weeks ago (ground your shit!!!!!), tolerates it, even plugged in to the outlet, but just barely. It will actually chirp the overload alarm. That’s an easy fix, I just need to add another breaker and outlet for it to the household power wiring. I’ve brought in a cousin who is an electrician to do the household wiring, and we’re waiting for him to be able to come back out and finish that task.

The same issue will arise with refrigerators. We have been using a propane refrigerator, bought used from a RV dealer. It works, but it’s a pain-in-the-ass, because it goes through so much propane. Since, even used, it cost me $1300, and it blows through a 20# tank of propane a week, it would have actually been more cost-effective to have simply bought a standard electric refrigerator, on the 5KW inverter system….(I’m familiar with the idea of using a chest freezer with an external thermostat plugged into it. We tried it. It didn’t work worth a damn for us, just because of the inconvenience).

The real moral of this isn’t how inexpensive a solar PV system can be built. We’ve covered that before, not all that long ago. What it is about is determining what you HAVE TO HAVE to live comfortably, if not excessively. What do you really need?

We can look at this from the rule of 3s….

Three minutes without oxygen.

Three hours without shelter.

Three days without water.

Three weeks without food.

Unless you’re on oxygen for health reasons, the only thing you’re really going to need electricity for is possibly ventilation fans, to keep stale air flowing, if you’re dealing with airborne contaminants outside of some sort, whether from an CBRN threat or smoke from wildfires, etc….

Three hours without shelter usually makes people think of staying warm in cold weather. Running electrical heat on solar is a non-starter. The demands because of inefficiency are simply too much. I’m aware that some people are running mini-split heat pumps that serve as both A/C and heat, but I genuinely don’t know how they are doing the heating side without it being ridiculously expensive.

More practical is what I mentioned previously. The use of strategically placed fans, with a properly designed house for the environment, will provide ventilation adequate to stay alive, and moderately comfortable. To be sure, if you’re used to year round climate control, and keeping your home frigid with modern A/C, it’s going to take some getting used to, but people forget, already, that the first practical residential scale air conditioning in the South didn’t come about until well after World War Two. (Carrier built the first electrical A/C unit in 1902. The first residential installation of electric air conditioning occurred in Minneapolis, in 1914. The first window unit was developed in 1945.).

One of the big applications of electricity in the household is one I’m currently trying to get caught up on, and that is running water. I’d like to stick with a 12V system, but the pump needs to be located far enough from the battery bank, on the opposite side of the house, that it’s not practical because of line loss. Instead, I will probably be using a high efficiency 110V pump, since it won’t run for long periods of time anyway. My backup water system, pumping water from the pond to the storage tanks in dry weather, when the rain doesn’t refill the tanks fast enough, I can get away with a 12V pump.

If I was in a place where I could install a water tower for an elevated, gravity-fed system, I wouldn’t need the household pump, but I would build a water trailer, with a large tank, and a dedicated two battery bank, small charge controller, and its own panel.

Three weeks without food. The electrical application to this is obvious. Sure, we can—and should—can foods, dehydrate foods, salt and cure foods, etc, but the convenience of a freezer, for both long term and short term storage and preparation, cannot be denied. I don’t know that I’ve ever met a “prepper” that didn’t have a chest freezer. Too often, their stated plan when the power goes out, falls back on a gas or diesel emergency generator. That’s fine, as far as it goes, but its not a particularly resililent plan, is it? After all, if you’re prepping for anything beyond a short-term power outage, what do you do with all that meat and food when you run out of fuel? Even the prepper porn fiction regularly discusses some woebegone prepper’s wife suddenly forced to cook up everything in the freezer before it goes bad, and sharing it around the neighborhood.

Now, I’m the last motherfucker out there that is going to suggest that sharing food with neighbors is a bad idea, obviously, but…wouldn’t it be nice if you had a way to keep that food a little longer, and share it out in a more rationed approach? I think so…

(I’m also familiar with the argument that having solar panels will just make you a target for thieves and raiders. Meh. If raiders/bandits/outlaw bikers/cannibalistic San Franciscans are going to be a problem, they’re going to be targeting anyone who seems to have anything, not just people with solar panels….The defense for that is not a lack of preparedness, but rather, is projecting security outward, and interdicting them before they get close enough for it to matter. That, of course, is the entire point of Volume One of The Reluctant Partisan….

Of course, beyond just storing food, in the freezer, electricity also facilitates food production in the form of electric mixers and food processors that can be legitimate labor savers. Most of those devices don’t draw a particularly large load, and they’re generally not used very long (the exception would be “bread maker” machines. Those abortions of inventions are not practical, in my experience, off-grid.).

Beyond those, really, the big demands for the off-grid system, from our perspective, is just the ability to keep flashlight batteries, etc charged, and those don’t draw much at all.

Ultimately though, whether you’re planning on moving your entire house off-grid (I highly recommend it!), or you’re just thinking about building an emergency power system to power a few key systems like lights and freezers and maybe charge batteries for radios and flashlights, you need to come up with a way to size your system.

Sizing your PV array is determined by available sunlight hours daily (generally in the winter, since that will be your least sunny season), and the kilowatt hours of your battery bank, and total wattage of your load(s). Sizing your battery bank needs to be based on your expected maximum daily demand. If you’re going to draw 1000 watts, for six hours a day, then a 5KWH battery bank (nominally a 10KWH battery bank, remember!), is not going to be adequate. Really, for that 6KWH demand, you’d want at least an 18KWH storage capacity, but again, as I mentioned previously, that’s not necessarily realistic, and it may not be necessary.

On Batteries

Typically, when you talk to solar off-grid folks, the first thing you’ll hear about is not the PV panels, but the battery bank. Most battery banks are built from reused forklift batteries. These are massive—really MASSIVE—batteries, and are typically 6V, instead of 12V. In order to get to a 12V system, you’ll need to wire two of them together in series, and then each series can be wired together in parallel. The advantage of the forklift batteries is that they are so massive, they offer a lot more power available per battery. The disadvantage of forklift batteries is that they are so massive, you damned near need a forklift to install them. The other disadvantage of forklift batteries is that they are generally procured used, and when they are used in forklifts, they are used hard, and a lot of times have been overdrawn repeatedly, throughout their service life. That means they’re probably not going to last as long as you would hope.

A bank built of 12V batteries will require more batteries, but they are much more manageable. Additionally, the availability of maintenance-free, deep cycle batteries makes them damned near idiot-proof (evidenced by the fact that I’m managing to deal with them successfully….). I’m completely sold on the Duracell DTG31AGM batteries I am currently using. They’re only 105ah each, but they are holding up remarkably well, and they are maintenance free.


"The time for war has not yet come, but it will come and that soon, and when it does come, my advice is to draw the sword and throw away the scabbard." Gen. T.J. Jackson, March 1861

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