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the smartest solar power setup i have ever seen  RSS feed

 
steward
Posts: 25161
Location: missoula, montana (zone 4)
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(I thought i had already posted this here, but i could not find it)

This is the sort of system I strongly recommend for anybody going off grid.  Normally, people get solar systems that have some huge array of panels and costs an enormous amount of money.  And then they have a HUGE battery bank, massive inverters ... 

But there was a time a few decades ago, when that sort of system would cost such a ridiculous fortune, that it was rarely tried.  Instead, when people went off grid and hooked up a solar system, they would learn some powerful lessons in how wasteful of energy they were when they were on the grid.  Suddenly, the cost of running a clothes dryer or an electric oven would be something like $2000 per year.    Soon you are drying your clothes on a clothes line and cooking on a wood cook stove. And your power needs drop to almost nothing.

Some of the most important points covered in this excellent video with Helen Atthowe:

  - two inverters.  A tiny one and a big one.  Keep them both turned off most of the time.
  - two 135 watt solar panels
  - two batteries
  - fixed panels
  - a largely DC system
  - wood heat



 
gardener
Posts: 709
Location: Manitoba, Canada
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This is a great video!

Does anyone know what she does for hot water?
 
Shawn Klassen-Koop
gardener
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Location: Manitoba, Canada
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Does someone in the know have an estimate as to roughly how much a system like this might cost?
 
Posts: 240
Location: Abkhazia · 400m elevation · temperate climate
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Maybe 1000?
https://www.bimblesolar.com/offgrid/12v/1040w-kit-mppt-used (too many panels, no batteries)

edit: a fast search on ebay for the individual parts:

Panels 2x260W: 300€
Inverters: 150€
200Ah @ 12V Deep cycle battery: 500€
charge controller: 50€
cables: 100€
--------------------
total: 1100€
 
pollinator
Posts: 329
Location: SoCal USA
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Depends on components, like most everything you can find each part in both cheap versions and pricey versions, and lifespans on parts vary as well of course. After getting a quote for $25k to get on-grid power to my new site which has similar winter sun hours, I'll be looking for a little setup with similar needs- a few led lights, a chest freezer converted to fridge temps, and charging of a tablet/laptop.

Initial plan to minimize fridge power needs is having it located in a pseudo-root cellar space, so (hopefully) the space itself will be cooler and reduce cooling needs.

Water heating will probably be through firewood, if the deer don't eat all my black locust sprouts! Cob Cottage Company uses a modified RMH to heat water for showers, with a water tank embedded in the mass. A small fire immediately heats the tank and within 10-15 minutes it's plenty hot for a shower. The other option is heating water as needed over a RMH already in use for space heating or a rocket stove built outside for warmer days, and mix with cold water to give yourself say 10 gallons of nicely warmed shower water or hot cooking water.
 
Posts: 111
Location: North central Ontario
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All and all that is a good system. I would change a few things though to bring it up to date or if I was putting it together today.
1) replace the small inverter with a morningstar 300 watt inverter it's standby losses are in the less than a watt range and it's pure sign. Less than $300 and she could cut out the filter which uses power.
Replace the charge controller with a more modern mppt unit. On a day like that and 270 watts of solar she should be making over 150 watt per hour with an mppt instead of 12 she mentioned. I think if you were buying new I would suggest saving the money on the dc freezer and buying an efficient ac unit and add a panel for less moneythan the sundanzer. Other than that a great minimalist system.
Cheers, David
 
gardener
Posts: 789
Location: Ohio, USA
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Excellent! I love it!

I would love to have a system like that, or any working system honestly.  I have plans for one, but not a high priority yet. Good to know 1 hour of winter light gets things done with two panels. I've been thinking of replacing the fake window shutters here with solar panels since that would be an easy clean and install. I have also been curious if a system of decentralized lighting and computer/phone chargers, given the improvements in solar technology, would be worth it, and then put the rest of the house on a higher voltage system. It would allow a scalar conversion to solar, no single point of failure for everything, and less manipulating of current.

I think an important point in this video is that multiple energy sources is key, "different tools for different jobs".

As holistic planning taught me. look at all your resources- cold weather, hole in ther ground...
 
Posts: 347
Location: Michigan
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135 watt pv modules cost double or more per watt than 290-350 watt panels, which range from 65 cents to $1 per watt. We have had good functionality on a single 185w module... not in the winter months. Most offgrid homesteads that are not minimalist are going to require 1000-2500w solar in order to achieve reliable capacity and autonomy and useful utility.

Still, many people have had utility from a single 50 watt module and every home or use is different in some way. Good example from our system.

The well pump is 1/2 hp and is sourced from a shallow well. On paper that is 377w rough. On the meter and supplied by a single (and always on) modified square wave inverter, 2600w (maximum continuous) the actual total power is 760w running. That is inverter losses and all, maybe a phone charger or 8 watt led or two.

Judging by the still shot, our home is much like the lady in the videos home. Now, with our main array nameplate of 740w (4x185 w modules bought ten years ago at $3/watt with shipping! (Ouch.), the output might hit nameplate on some days for a short time. With the addition of 275w the output can easily be 750w for long durations on many days.

The available direct solar power is then right about at the energy draw of the pump! So no wear on batteries and storage remains full during use under full sun.

The clothes washer.... we used to hand wash all clothes and sometimes go to a laundry.
The closhes washer use requires some overlap with the well pump running, 1460w total and about 600 watt-hours. We can easily do laundry, middle of the night up to the fourth day of low sun availibility.... but we dont.

The clothes washer in winter.... in the winter or during long strings of cloudy days (michigan), i flip an array breaker that connects an additional 420w pv array. This brings available power to 1430w, nearly the max occuring demand of our entire home electrical system and appliances!

Now on any half sunny day we can do a couple loads of laundry and still have full batteries within a short time of finishing. As long as this is done by 1pm

I will do a marathon of laundry and reserve it for a sunny day and pretty much bypass the battery and have just about 1:1 direct washing until about 1pm.

Same for our electric chainsaw. 1800w, but cutting is not constant. I can cut wood and before i put every thing away and come to look at battery soc, its usually full again.

The clothes dryer...
we have a dryer it would be nice to use but it is not in our budget or need. I built a 14' tall A- frame that is a lever to tension 4, 35' long lines to hang clothes on. The other end is a cross bar, attached with a ratchet strap to a huge oak. It will hang 5 loads of laundry with about a foot of sag. Solar clothes dryer.

The winter dryer... we have stainless steel safety wires drawn dead taut in the main living area about a foot below the ceiling. Most people dont even notice it unless we have clothes or herbs hanging. These lines are stretched 16 feet across the room and infront and above the woodstove! Solar dryer.

Our wood stove heats space, heats water, dehumidifies when needed, cooks the food and dries the clothes about 7 months of the year and even though it is my slave driver, it is my favorite appliance for its utility, though i do not like to destroy or misuse the biomass. We only burn dead trees, but i still feel sorry for doing so and we are transitioning to as much solar heating as we can afford.

The actual solution should be to not live in a region where heating is required.

Another upgrade for our system is the morningstar inverter that David mentioned. I recommend it often. It is great for lighting and communications/entertainment and would allow us to turn off the large inverter most days. Our inverter requires about 300 watt hours a day to keep on.

One more thing. The price of pv modules, last season was as low as 50 cents a watt.... same panels today, 85 cents. If you are going to do this i would do it now. The price is artificially low and it will not hold. We are going to have $3/ watt costs as we use up the silver and other requirements of their manufacture. As more of the world population must resort to solar power to keep afloat, there will be rising prices to cover profit and cost.

It has to do with price controls, subsidies (theft by force again, you will be caged or killed for not submitting to cover 90% of the industrial costs before you buy!) and market manipulation. The system is a fraud and we cannot actually afford all this, it is being stolen from current and future generations and produced by varying degrees of slave labor, even in the "free world".

A gallon of gasoline has an actual cost of $25-$30 a gallon not including environmental, health, and security (theft by warfare and overt force) costs.

How much do you think a new alternator costs for your car?.... i would wager that a high quality, non slave made alternator actually costs 10-20 times at least, the $200 store tag. You cant afford it, most cannot, in actuallity afford it and if it is to be slave made and produced without care for the environment, it should not be allowed at all. That is a durable hard goods, what about tires?

The photos are a contrast between my personal system and the ones i design and build for clients.
Theirs, 8000 watt outback, 21kw diesel genset, 1100ah 48v battery, powered vent for insulated battery enclosure, cobra cables or equivalent and an 8500w array to be installed next month.

Mine, cheap but good powerbright 2600w inverter ($250modified square wave even), outback mx 60 charge controller, and a 440ah 24v battery built from high quality golf car 6 volts, no genset and about 1400w pv array 150 feet from the battery, repurposed "gang" box tool storage locker with thermosyphon vent.



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gardener
Posts: 1470
Location: Ladakh, Indian Himalayas at 10,500 feet, zone 5
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Nice, timely post for me to read, as I'm about to set up my own solar set-up soon. I've been living on solar power at the school I've lived at for over 20 years, but am about to move into my own space. Both at the school and in my new place, the heat is passive solar only as well. The electrical demand is only lights, computer, phone. At the school also loud music and a TV or projector. In my new space I want a fridge (ooh, luxury!) though.
 
frank li
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Location: Michigan
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Rebecca Norman wrote: In my new space I want a fridge (ooh, luxury!) though.



Ha!

https://youtu.be/ue7wM0QC5LE
 
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Hi, all. Paul thought I might post something here in case anyone has questions about Helen's cabin system. Sorry, I don't have any more "Quiet-tone filters" (the most common question I got from the video). I tried to disassemble it to see what was in it but it was all potted in tar.

Someone mentioned 135W panels being too expensive. Indeed they are nowadays. When we built the cabin system, they were the best price point commodity panels at the time. Now the larger panels in the ~250W range are the best value.

My goal was to keep it simple and affordable, not to power a typical American suburban home with all the same electrical convenience you get from being plugged into Grand Coulee.

Key features are:

1) Do as much with 12V DC as possible. Yes, higher DC voltages make more efficient use of wiring, but there is so much stuff you can get off the shelf that runs on 12V that that alone outweighs the possible need for more copper.  You can get 12V LED "corn" bulbs that screw into regular light bulb sockets, so you can use whatever nice-looking light fixtures and lamps you want. You might have to order them straight from China, though. You can get mini versions of most kitchen appliances that run on 12V (truck stops are a good place to buy them). The cheap, easy-to-replace inverters are all 12V. Car adapters for all your electronic gizmos are 12V. You can use a 12V car stereo in your cabin or convert a boom box to 12V, as I did for Helen. You can also get good 12V refrigerators and freezers, although the better ones also come in 24V models. When you run all this stuff on 12V, you can leave the inverter(s) off most of the time, which saves energy and eliminates fan noise. I mounted cigarette lighter sockets in deep outlet boxes and made my own cover plates by punching standard blank cover plates with a Greenlee punch. A person could also use a step drill, especially in a plastic plate. Although there is no real standard for 12V outlets yet, and the code allows 240VAC outlets to be used for 12VDC in a building where there are no 240VAC outlets actually hooked up to AC, I prefer sticking with the most standardized thing out there, and that's the old cigarette lighter outlet. By having those outlets, if your friend comes over and wants to charge their cell phone, they can just plug their car adapter in and they're good to go.

2) Set the panels steeper than the latitude-based calculations say you should. The latitude calculation is for maximum year-round energy production, which matters if you're selling into the grid. But if you're off-grid, what you really need is to maximize your production when the sun is low in the sky and the days are short.  In the summer there will be plenty anyway. Steeper also means more likely to shed snow.  Sun trackers aren't worth the complication these days, given the decreasing price of panels.

3) Use an MPPT charge controller. They not only get 30% more power out of your panels, on average, but more importantly they make the difference between charging a little bit and not charging at all on cloudy days. The cheap no-name ones you can buy direct from China off of Ebay for $100 or so seem to be okay, although of course documentation is poor.

4) If you're really strapped for cash, use whatever batteries you can find cheap or free to get started. 12V batteries connected in parallel don't have to match, although a shorted one will drag the whole set down. Flooded batteries are more forgiving than sealed batteries, as well as being cheaper. They will withstand more abuse, like over-charging, because you can "doctor" them, and add water as needed. A pair of 6V Trojan batteries is great, but an RV/Marine battery from Walmart is a lot cheaper and is a good way to start. Beyond that, old batteries in variable condition scrounged for free out of junk cars, so long as they aren't shorted, are a whole lot better than nothing, and the price is right.

5) $1000 should get you a system that's adequate for a small cabin.
 
frank li
Posts: 347
Location: Michigan
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David Sherman wrote:Hi, all. Paul thought I might post something here in case anyone has questions about Helen's cabin system. Sorry, I don't have any more "Quiet-tone filters" (the most common question I got from the video). I tried to disassemble it to see what was in it but it was all potted in tar.

Someone mentioned 135W panels being too expensive. Indeed they are nowadays. When we built the cabin system, they were the best price point commodity panels at the time. Now the larger panels in the ~250W range are the best value.

My goal was to keep it simple and affordable, not to power a typical American suburban home with all the same electrical convenience you get from being plugged into Grand Coulee.



Yeah, i said that! Not a critiscism though! We have much the same modules and probably just a little later than yours, when a 185w was a bigun.

The battleships that we install for people are for homes that are 4, 5, 6 people families, farms, large residential homes and supply all the homes energy, car charging, geothermal and airsource heat pump space and water heat, home mechanic and workshops, etc.  Those are in the 12-20kw range, very few 20kw residentials, usually 12-15kw for these applications.

For offgrid cabins and seasonal homes, generally we are installing about 2-6kw, the majority about 2kw.

It is a lifestyle thing. Different folks and the offgrid installs and families are my favorite to be around.
there is something drab about installing the "smart investor" system... no great homeschool kids curious and courtious, no cool animal mascots, no intent to settle in and enjoy time on the land, just accumulating and protecting wealth.
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Posts: 571
Location: Bendigo , Australia
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fabulous
 
Posts: 95
Location: Western OK, avg rain 23" hazards: drought, tornado, wildfire
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What about hail? The western Oklahoma county I am moving to gets hail three to four times a year.
 
pollinator
Posts: 400
Location: South West France
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Denise, we're in South West France and several times a year, we're bombasted by extremely large hailstones during storms.



They have smashed the vacuum tubes on our solar water heaters, split polycarbonate sheets, dented our van and ruined tarpaulins covering our hay - but after almost twenty years, our photovoltaic solar panels are still intact.
 
Posts: 33
Location: Cambodia
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People, all too often, tend to set up a solar system - then try to sort out what they can run off it. Rather than doing that, it is best to determine what sort of loads you wish to power from the system, and make your calculations for batteries, controller, and panels, accordingly.

Calculate how large of a battery bank you need to run a given load (watts) for a given length of time (hours) and total your watthours. If using FLA (Flooded Lead Acid), AGM (Advanced Glass Mat) or other sealed batteries, make sure they will not be depleted more than 50%.

From there, you can calculate the the appropriately sized solar panel array to keep the batteries charged. After that, you can determine what size controller you need. MPPT (Maximum Power Point Tracking) controllers are more efficient than the old technology PWM (Pulse Width Modulation) controllers. But, they are also considerably more expensive. Personally, I would NEVER buy Chinese made garbage controllers. I have personally tested a number of them. I would never let them determine the charge going into my very costly set of deep cycle batteries. But, that is an individual choice to make.

Do not do it the other way around, or you will end up costing yourself unnecessary expense.
 
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