Introduction: Off the Grid Shed-cave

Picture of Off the Grid Shed-cave

Before completing my workshed/mancave, dubbed the Shed-cave, I knew I would be needing an environment in which I will be able to operate my electric power tools, charge the cordless batteries and smartphone, work late in the night, and relax with T.V and games without installing a subpanel or siphoning power from the house via an extension. It was then I decided that my epic build (a simple 12x12 shed) would not be labeled complete until it's off the grid. So I would build the shed by day (6 months working between work). And by night, like the modern researchers of our time, armed with a cup of joe and youthful (middle age) enthusiasm, I clawed my way to the computer to bravely begin my quest...Cortana, search for free energy.

Word of advice! Free energy equipment can be very pricey so please have a budget in mind. It's always best to start small and add as the need arises.

Step 1: What I Need for Free Energy

Picture of What I Need for Free Energy

Google informed me that for a basic free energy system setup I'm going to need: a power source; something to regulate the power; something to store the power and something to convert the stored power to usable AC. In other words, I would need solar panels or/and a wind generator; a solar and wind charge controller; batteries (deep cycle preferably) and an inverter. My intention was to harness both solar and wind energy. However, since I was only able to complete the solar, from this point forward the information given will be about harnessing solar energy.

Step 2: Power Source

Picture of Power Source

Before purchasing solar panels, one should determine how much energy one will need. It's the batteries that supply voltage to the inverter. Nevertheless, if the batteries are being depleted faster than they are being charged, then there will be a problem. Solar panels should be able to keep the batteries adequately charged. Because of my intended usage for the Shed-cave and my budget, I decided to go with a 12V 100w Polycrystalline panel. This would provide me with 5A of current in direct sunlight. And as I mentioned earlier, if I need more I can always add. The panel cost me on the Bay $98.34

Ps. There are other types of panels monocrystalline (more expensive) and higher panels with higher voltages 24V.

Step 3: Location of Power Source

Picture of Location of Power Source

Most people find it easier to install the panels on their roof. But owing to the location of my Shed-cave, the roof (too many trees) was just out of the question for me. Also, the panels have to be clean from time to time (panels on roof = too much work). I needed a sunny spot that was close to the shed. A spot where I would have sun both in the summer and winter months. After watching the sun rising and falling for a few days, and the consultation of my resident solar astronomer (my wife the Gardner) I choose a location just 19 ft from the shed and about 24 ft from the charge controller and batteries.The proximity is important because it helps to determine the size wires I need to efficiently transport the juice to the batteries.

I then chose 10 AWG solar wires. Research showed that 8AWG would have been ideal (bigger wire=less heat loss over the distance). But in the imperfect world of not having all the resources at one's disposal, the 10 AWG wire would have to do. If I ever decided to add 2 more panels, in parallel, to draw more current, then I will have to increase the wire size. I found 1 pair of 50ft wire with MC4 connector for $33.85 on the bay.

Next was the mounting of the panel and the laying of the wires. The panel needed to face a southerly direction because I'm in the northern hemisphere (and I thought living in the south means I was in the southern hemisphere) and it had to be angled at certain degrees each season for maximum solar rays. You can also leave it fixed at a set angle. A quick search will yield how to calculate this. I chose to adjust the panels twice a year, summer and winter. So I built a tiltable solar mount with material from Home Depot $40 + some wood scraps I had. I also bought the electrical conduits from the big box store.

Step 4: Regulating the Power

Picture of Regulating the Power

Connecting the batteries directly to the panels is a very bad idea. Your batteries will be damaged and possibly explode from overcharging without a regulator or controller. Spend a little more, and save more the long haul.

Controllers ranged from the basic 1 or two-stage controls to the middle range PWM (pulse width modulated) to best MPPT ( maximum power point tracking). The best is always more expensive. Furthermore, I needed a controller that can also handle wind energy. So I chose a 12V 400 amp, 10k watt charge controller for wind turbine and solar panels from Missouri Wind and Solar which only set me back $69.78 on the Bay.

Step 5: Storing the Power

Picture of Storing the Power

When I first start this project, I immediately thought that a car battery will be able to work. Afterall a battery is a battery and car batteries are reasonably priced. But I was soon schooled by the Internet University. Car batteries, even though they can work, would not be adequate for long-term storage of energy. I would have to use deep cycle batteries. Of course, anything deep would mean I have to dig deep in my pocket. These batteries are rated by the amp-hours. The more amp-hour a battery can give, the more it is going to cost. I settled on a 12V 35ah battery. In fact, I bought 2 which I connected in parallel (to increase current and maintain voltage). This would theoretically double my amps but keep the battery banks at 12V. This set me back $122.95 on the Bay.

To connect 2 batteries in parallel, you connect the positive terminals together, and the negative terminals together. Then the load and/or source is connected to the positive terminal of one battery and the negative terminal of the other. I used 1/0 AWG pure copper wires for the connecting of the batteries. This ensures minimum power loss between the battery connections.

I failed to mention earlier that your voltage rating needs to remain the same throughout your devices. That is, if you are using 12v panels, you need to use a 12v controller with a12v battery array.

Step 6: Converting the DC to AC

Picture of Converting the DC to AC

The current up to this point is DC. In order to operate your appliances and tools, you need the convert this DC to AC. This is where an inverter comes. Inverters come in different wattage. Also, there is the continuous watt and the peak watts. For instance, a 500-watt inverter could have a peak watt of 1000. The peak would normally double (or more) the rated watts. This peak watt is important because most motor devices need to double its wattage (called a surge) at start-up. For example, a 120v 5.8 amp device needs 696 watts to run continuously (P=IV). However, it needs 1392 watts to get going.

Then there is the Pure Sine Wave, Modified Sine Wave, and the Square Wave inverter. The PSW is more expensive and should do all that you need without no problem. It's the same wave you get from the utility company or a generator. It is reported that MSW inverter causes some batteries to overheat while being charged, along with noise in some lights, and malfunctioning of some motor devices. SW is the cheapest and the most problematic of all. I'm using a Radio Shack 350W PSW inverter that I had for a number of years now. I will have to get a higher wattage PSW inverter ( 1.5kW / 3kW ) in the future.

Step 7: The Connection

Picture of The Connection

Choose the best location to mount your devices. Follow the manufacturer recommendations for connecting your panels to your charge controller and the controller to the batteries. I used 10AWG wires for all my connections from the panels to the batteries. I added a Watt Meter between the solar panel and charge controller and a power meter on the inverter. This is just to monitor what is coming in and what is going out. Not necessary for the operation.

I used a breaker box and ran a couple of switches and outlet (using a power strip would work just fine). I also connected a 20w and a 5w light.

It was also recommended to add ground (earth) to the circuit. So I added 2 (1 for the shed and 1 for the solar panel) and grounded the batteries; charge controller; inverter; solar panels and breaker (pretty much anything with metal).

Step 8: Tada

Picture of Tada

One of my testing setup.

Step 9: Tada #2

Picture of Tada #2

That's all folks. I hope this information was of some assistance.

Comments

BobH160 (author)2018-01-09

Thanks for this. I have been planning to do a wind and solar install for my garden and have been reading about all the bits but I am a visual learning person so seeing this gives me a better insight as to what I will actually need.

Born_to_build (author)BobH1602018-01-15

You are welcome! Go for it.

Aaaecm (author)2018-01-09

Again, very inspiring. I want to provide power for some light applications in a fairly remote location. This would make that possible. PLEASE keep posting. Your Instructables are well written and easy to understand. Enjoy your Shed-Cave. You're doing it wrong if you don't.

Born_to_build (author)Aaaecm2018-01-15

Thank you!

charles543 (author)2018-01-09

5A at 12V is 60W, not 100W. AWG 14 wire would be more than adequate. It is easily good up to 15A.

GeneB21 (author)charles5432018-01-10

Charles yes 14 ga wire will handle 15 amps without melting but its about your restive line losses at 12 volts for any distance more than 10 feet or so. I run a MPPT system where I series 5 160w panels to kick the voltage up to about 70 or 80 volts keeping the amperage total to one panels worth (9 amps) thus keeping my restive losses down on smaller, cheaper wire.

I am seeing you are getting a lot of info besides mine. Cool! When you parellel your panels as with PWM the voltage stays the same but your amps add up as does your wire gage requirement.

SO MUCH TO LEARN!

GeneB21 (author)GeneB212018-01-10

Shoot we haven't even gotten into monocrystalline or polycrystalline panels. Thats a biggie!!!

Born_to_build (author)GeneB212018-01-11

I know, it is a topic worth exploring. What's your input? Are they worth the extra cost?

GeneB21 (author)Born_to_build2018-01-12

Is what worth the extra cost? I have done two write up for you and lost them both. Posting here sucks! I am tired of writing so may try later, or not but here is a picture of my retirement set up at the curb. I have found an off grid spot where I can park, gathered, bought, bartered and scrounged everything I thought I would need over a three year period and will move in to start assembling it all soon as the weather breaks

Born_to_build (author)GeneB212018-01-12

My apologies Gene, I was referring to Monocrystalline panels. I know they are better and more efficient. But are they worth the extra cost?

MichaelS440 (author)charles5432018-01-09

Interesting part of the topic. "handling" may not be the best way of looking at the needs. Interestingly, he is using a PWM charger. PWM chargers simply cut off the voltage not needed and make sure the battery is never charged above a certain voltage. The 5 amp figure is not improved on, and is the maximum.

But, if a person were to use a MPPT charger, then the maximum WATTS delivered to the charger becomes important. And a reduction of WATTS caused by resistance in the wiring can be important. So, one would need to determine the resistance, and thus voltage drop, of the wire to determine if it is lessening the total power in WATTS delivered by the panel.

I have found a solar charger from Ebay, China, MPPT , that was reasonable, but many are very expensive. And I Haven't tested this charger yet. I do think it isn't a fake though, as I looked at other reviews. I've always said that if you are limited on the number of panels you can have by some sort of sq footage, real estate, like on a boat or RV, then you should always use MPPT. But that's another topic, somewhat related.

Whenever you have more info, please share. The cost of MPPT's is why I chose the PWN.

GeneB21 (author)Born_to_build2018-01-10

I actully have ended up with two complete systems. PWM Bogart 12 volt with a 1k full sign inverter on the bus integrated with the buses electrical system for mobility. That was my starter system also That way if shadows fall across the 2 panels mounted in parallel on the roof I still can get output. Then in my 16ft Hallmark trailer/shop/moto hauler I have MPPT 24 volt system with 4 230 AH Everyready deep cycle 6 volt in series and 5000w continuous, 20,000 peak full sign 110vac inverter/80 amp 24vdc 4 stage battery charger/ups unit. As I said, I got a little out of hand on redundancy...bring on the apcolipse I am close to ready

Born_to_build (author)charles5432018-01-09

I Agreed. The actual panel spec: V=17.2v and A=5.81. According to the calculations, the distance from panel to the batteries should factor in the determining the size of the wires. This is important for efficiency (smaller wires generate more heat over the distance). Mine was a distance of 24ft. Also, I will be adding another panel in parallel in the future.

steddie1 (author)2018-01-09

This is a grate 'ible! Very well-written and informative! I have been contemplating building a shed of my own, but wanted power, and wasn't too keen on working with running power from my garage, as I am not "electrical-savvy". I was always interested in off-the-grid power, but didn't think it'd be that simple. Thanks so much!

Born_to_build (author)steddie12018-01-11

Go for it. The journey form shed-solar has been a memorable one.

Michael Kevin Pipe (author)2018-01-09

Thanks for the time & effort you spent teaching us. I'll be moving to Arizona this fall & leaving behind my mancave/garage. It's 24' X 24' divided down the middle , Then 1 half is divided again. #/4 tongue & groove plywood paneling (got a SUPER deal). R-19 insulation. Such a wonderful place for any man. Tools of all description, Hardwired computer desk, 100w sound system & 48" flat screen TV. And the most important? A locking door& NO windows. I will miss it terribly. So I'm taking your Mancave to heart! I will change the size a bit, increase the solar & start all over. Who says you can't teach an old dog new tricks! I've got news for them! Thanks again. (Maybe I'll post my adventure? ;-)

You are welcome. I hope you will post it. We can all learn from each other's experience.

IvliaV (author)2018-01-09

Great article, but you don't have to have sunlight for 'solar' power. I recently attended our local Ideal Home show where I was looking into solar panels to make my home as much off grid as possible. I found the local installer for a new type of solar panels which were/are developed and built in France and which operate using daylight without needing sunlight (ideal as I live in Ireland where sunlight, especially in the winter, can be very elusive). I am waiting for the installer to contact me with prices etc. but they might be ideal for those who don't have access to regular sunlight, either because of where they are living or because of the position of the building eg: under trees. Hope this helps somebody can't put conventional panels up for whatever reason. Probably expensive but I was told that they are able to be taken with me when I move, are more cost effective over all because all they need is daylight - even on a winter day when it's clouds and raining outside - and have a long life span.

GeneB21 (author)IvliaV2018-01-11

Ivila all solar panels work without direct sunlight only with greatly reduced outputs. Efficiency is the key. I do not think you are getting any magic solar panels. What they are probably using are monocrystalline panels in series for high voltage into a MPPT type controller. This is a very efficant set up and a soon as the horizon lights up in the mornings, my system is charging.

farna (author)2018-01-10

Pretty good basic system. You're going to need deep cycle lead-acid batteries to run power tools, and of course more charge and inverter capacity. I considered running the lights in my 30-50 shop off solar -- didn't want to attempt much more due to high cost of a system to run power tools any length of time. Could have used four deep cycle batteries and a 1500W inverter to run the fluorescent lights (and a few CFLS) for 5-6 hours a night. After the math, wasn't worth it. I was in the shop at night maybe one day a week for a couple hours, maybe a couple days a month I used lights on cloudy days (on average). Would have taken me 10 years to use enough electricity to cover the cost of the system, including changing the batteries out once (would last 4-6 years, depending on use.. and I had some excess capacity to prevent drawing batteries down too low or fast). With LED lights I could have reduced the system to two large deep cycle RV batteries, but would still be the same.

What you plan should be pretty good for using your cordless tools, recharging the batteries will probably take more than you have now, but 1000-1500W should do it. I don't know that I'd shoot for use of regular power tools. Draw is just too much (10-15A -- 1200-1800A). Bury a line from the house for that -- just one outlet. You could use an HD extension cord... but make sure it's under ground rated. You can get underground rated wire, not sure about an extension cord, but you can put a male plug on the wire to tap into an outdoor outlet instead of hard wiring, if one is nearby.

According to the calculators at https://www.wholesalesolar.com/, you would need 14 6V/430AH deep cycle batteries to run a 15A table saw for three hours a day for 1-2 days, drawing the batteries down to 30% capacity. That's three hours of actual cutting, as the motor would only draw max output under load. I estimate that to be a fair time, you'd have to be doing a lot of work to actually run the saw much more than that, and you could use cordless tools for some work. Your power tools may only draw 10A. Based on the worst case 15A draw, that's $4550 in batteries (from Wholesale Solar, using free shipping). Then you have to increase capacity to be able to recharge those batteries adequately...

GeneB21 (author)farna2018-01-11

What farna said. Occasional use of a power saw or the such is ok but if you are doing projects you best have a 6 to 10k generator to run your shop. Even if you battery and inverter up you have keep in mind if your tool draws 10 amps at 120 volts, the double on start up you will be slugging your 12 volt system 200 amps starting and 100 running. That beats the living shit out of your batteries and any loose connections ANYWHERE are going to melt. Now to run my welders, forget about it hahaa crank up the gen set!

Born_to_build (author)farna2018-01-10

I appreciate this information. The power-hungry tools (table saw, miter saw, and drill press) will not be on a continuous daily basis (30min of actual usage when using) and those I definitely will use at high noon. On the days when I'm working late evenings and nights l primarily will be using the cordless tools. The system then will be running the Tv, and lights (5w /20w) and at times the PS3. I was using a line from the house but I wanted the off-grid experience for the Shed-cave.

I try to focus on my budget ($1k or less) more than the math. If I follow the math, I probably would not have taken it off the grid.

erik.nottleson (author)2018-01-11

So far, most of your loads are dc - cordless tools, computer. Would I seem smarmy if I suggested you investigate a dc/dc xfrmr and create a dc power tap off your battery bank? Yes, you’d need to kludge a dc connection for the tool battery charger, and a new cord to bypass the PC’s ac/dc inverter. But you’d avoid 2 stages of conversion losses.
No, I haven’t done this. Your use of 12v lighting prodded the question into my head. It’s a nice project you’ve already done and this is only a question in case you get bored.

GeneB21 (author)erik.nottleson2018-01-11

Eric you have to be very careful charging batteries in today's tools and devices so kuldging together a cheater cord to directly charge say a lithium battery could get you hurt or worse. Burn down that shack in the woods, then maybe the woods just because that is what fire does.

Nothing says that if your device has a charger cord for your car that you couldn't do that though,

JohnJeiJei (author)2018-01-09

Very nice (and tempting to try)! Pardon if these questions don't make sense, but i know very little about this electric stuff..

Did you mount a single 12V 100W panel? Does it provide that much current?

What can you actually power through that 350W inverter? Just a couple of lights, a small radio and a 100W jigsaw?

I'm asking because you mentioned power tools. What kind of setup would you need to power, for example, a 2000W circular saw (for light use, of course, not a permanently running table saw)? This while providing light, and charging the batteries, with enough left over to power your gaming session at night..

How long would those batteries power your work/play session under average use (say, 2h of gaming, 2-3h of working with various powertools)?

Cheers,
John

Born_to_build (author)JohnJeiJei2018-01-09

Because of the cost involve in setting up off-the-grid systems, I decided to start small and add as needed. This is a basic system which meets my winter need for the shed. When my work picks up in the spring, so will my power consumption. Most of the tools I use during this time are cordless tools (circular saw, jigsaw, drills, etc). Presently, I'm deciding on the best heat source so I have not spent more than an hour each time in the Shed-cave. So far I have tested it running a 5W light, gaming, charging a single battery but mainly during high sunshine days. Battery holds up with not much drainage during this time. There is still more test for me to do. I know what the theory says, I just want the practical base on my specific location, design, and application.

You can use this same setup with a higher wattage inverter. A 2000W circular saw will need at least a 2000W inverter with a 4000W surge. I would use a 3k/6k inverter just to be safe. Light use, while the sun is shining, would work even though it would be a great demand on this system. You would see a significant drop in battery voltage.

My thought is this, the more the demand, the bigger the supply has to be. The more power hungry tools I use, the bigger the battery (ah) and/or more amps to keep the battery charge.

I will be purchasing a 1500w or higher PSW inverter in near future. This will power my table saw and higher amperage tools. I also will be adding another panel and batteries. I intended to spend some good quality time in the Shed-cave.

JohnJeiJei (author)Born_to_build2018-01-10

Thanks for the detailed response!
I have a tiny shed as well, and was thinking of a similar system to run some power tools every now and then (even smaller power ones, i can run a power cable from the house for more power-hungry tools).

But there's another thing i need to take into consideration: I'm probably not going to use it that often, which will probably mean a surplus of power that is not consumed. Any idea how the system might cope with such a scenario? Will this degrade the batteries, charger, inverter, panels, whatever?

Thanks again,
John

GeneB21 (author)JohnJeiJei2018-01-10

John that is why you put a battery controller on there. These systems are pretty much made for your scenario as is. Also remember that you do not want let your lead acid battery's ever drop under 50% and if you want them to last you will keep them above 70%. There are so many things to consider when wanting to have a system that you can live with rather than camping..such as PWM controller or MPPT, three stage or 4 stage etc etc.

Now that being said your write up on this basic system is awesome, it is a great start as this is a pretty steep, and expensive learning curve to grid independance. I have been at it over 3 years and have close to $3k so far into it and I am a good scrounger. I had to stop because I started obsessing on my electrical system redundancy. Also understand I have a 10kw generator as my supplemental/shop power because you absolutely have to keep your batteries charged up rain or shine, using or idle.

It has been a lot of fun so far and a great learning experience like a hobby. Right now everything is packed up and unfinished but once I move back into the bus and get back to work on it I will write it all up with photos the works...so much

JohnJeiJei (author)GeneB212018-01-11

Thanks a million for the replies, this is why i love this community!

Looks like you put a lot of thought, dedication and other work into your system, so i'm looking forward to your write up!

Born_to_build (author)JohnJeiJei2018-01-10

John, as Gene stated, the charge controller regulates the current going to the battery. It prevents the battery from overcharging by cutting off the juice from the solar panel. The charge controller and watt meter gets its power from the battery so a small amount of power is being used by the system. I can hear my controller clicking off as it maxes the battery capacity and then on as it drops below. This happens while the inverter is off.

According to the research, it should not affect the components. As Gene said, it was made for such operation.

GeneB21 (author)JohnJeiJei2018-01-09

John I can help you with that answer...NO! This system is so small it will barely run anything other than your phone and laptop chargers on your weekend trips to the cabin.

As far as gaming you would only be able to play in the full sun maybe an hour AFTER you let those tiny little batteries charge fully. You only have 100w of generating power panels before you even minus your electrical losses in the system. Barely enough to shock a piss ant.

Here is a calculator you so can get a rough idea what you need to get to create what you want. https://solarcalculator.com.au/off-grid-calculator... .

It ain't that cheap to get into all that free power trust me, I just went through the process myself for my off grid mobile retirement living set up. Maybe I should do me a write up.

Born_to_build (author)GeneB212018-01-10

I'm with John, I believe your experience will be a tremendous benefit to this community.

JohnJeiJei (author)GeneB212018-01-10

Thanks for the reply, and you definitely should do a write up!

GeneB21 (author)GeneB212018-01-09

I want to add whatever amperage the panels put out at 12 volts has to be divided by 10 when you boost the voltage to 120. So say the panel puts out 10 amps in full sun, after losses and voltage boost you get less than 1 amp of usable delivered to your 120 device.

foodforall (author)2018-01-09

Thanks for this great Instructable-well written, and explained in simple to understand terms. So whether you know a little or a lot about these things, it was informative and encouraging. I am saving the instructions for some farm site related work that will be happening this year and this design will be perfect--maybe I'll even post pictures! Thanks again!

Born_to_build (author)foodforall2018-01-10

You are welcome! I do hope you will share your experience. There is still so much I need to learn about this free-energy operation.

EricB142 (author)2018-01-08

I'm assuming you forgot to photoshop the battery pic.? 6 + 6 = 6?
Consider : 6 vdc "golf cart" gel batteries in series to produce 12 vdc & you can discharge the 100% , unike 50% without damage.
FYI

GeneB21 (author)EricB1422018-01-10

Be sure and bring your wallet full of cash for gels or AGM's that size. They are lighter, need no maintenance but they only last half as long, need higher voltages to charge and actully do not pencil anywhere near as well when figuring cost per hour of power over the stretch. I was not going to get into this yet. Besides I got to get out to the bus and work on it today (:

Born_to_build (author)EricB1422018-01-08

Thanks for your keen observation. The picture was intended to be used as an example of a parallel connection and not a 12v battery array. I guess it does make sense to use a 12v example since I'm talking about a 12v system.

Yes, the first thing I noticed was the batteries were set up parallel which is incorrect. Suggest you re-load this or have instructables re-load this with the correct graphic. Wiring mistakes are serious.

Nikiniku (author)2018-01-09

You left out some costs. What was the total cost?

Born_to_build (author)Nikiniku2018-01-09

The actual cost including all the wiring, the led lights, the materials for the panel and the watt meters $578.24

BrianB245 (author)2018-01-09

This is a great presentation. 'm sorry I have one very basic question - when you say you 'earthed' some of the gear, I understand why you do it but what do you actually do to 'earth' it? Thanks

Born_to_build made it! (author)BrianB2452018-01-09

I bought an 8 ft copper rod from HD, cut it in half, and hammer them in the ground. I use ground rod clamp and attached 8AWG wire for the shed and 10AWG for the panel.

NikB5 (author)BrianB2452018-01-09

You drive at least a metre long piece of steel into the ground and attach your earthing cable. In the event of a short it travels literally into the ground and dissipates.

vkanaga (author)NikB52018-01-09

Copper rod would be better but yes you can use steel. Steel will breakdown is the soil over time more quickly and depending on sediment type may even separate from grounding with oxidation.

NikB5 (author)vkanaga2018-01-09

Don't they bond the copper onto the steel rod usually as a core ? Most of the ones I have used have been stainless here in the UK.
But you are right if the soil has a high salt content then copper rod would be best.

seamster (author)2018-01-05

Very nicely presented, thank you for sharing this info!

Born_to_build (author)seamster2018-01-08

Thank you for your encouraging words.

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