View Full Version : Solar Home power off grid

2nd Mar 2015, 04:29
Just wondering if any here have done the off grid electric here like I have done.
I started out buying my land.
Cleared it, started building home.
Ask power company for temporary power pole.
They denied.
So I started this adventure and at the point where i could qualify for temp power pole i found I did not need it.
Yes wont handle Air con, but for normal lights TV, computer and washing machine etc why do we need mr. Edison?
Earls power company will power all.
I have a home in the Philippines also, put air con there everyone got sick.
Remember here in USA was 15 years old before we had air con.
Think maybe power companies on the way out just like phone companies.
Hope many doing this now.

2nd Mar 2015, 05:48
I am considering going this way due distance of my possible plot from the next electricity source. I would be interested how you did it as I am collecting the data about such solution at the moment.

2nd Mar 2015, 05:54
All depends on what sacrifices and cost your prepared to put in. Power companies are here for the long term I'm afraid. Even a lot of stations out here have a lot of renewable, but still have diesel supplement.

In effect unless you are prepared to actively sacrifice at times and have redundancies, you still rely on the pole.

2nd Mar 2015, 08:01
My poles are bamboo. yank next door has wind gen and water collector/


2nd Mar 2015, 08:43
It always amazes me that folks will put with the inconvenience of no gas, electricity, adsl tv, water ...
... just for the inconvenience of living in an inconvenient place.

cockney steve
2nd Mar 2015, 10:36
Ah, Well, Mr. Toffeez... the pace of life alters and you soon realise what is really a necessity and what's just nice to have.

Yes, I have the modern conveniences, but I shut down the Central heating a few years ago and never bothered turning it on again....see, it's nice to come into a warm, toasty, (wasteful) house, but a gas fire in the living room and a 'leccy blanket on the bed are adequate and stretch the budget.

My Slough-based sister thinks i'm mad, masochistic and hard as nails, the soft southern jessie....there again, she still works part-time and she's older than me, in order to maintain her profligate lifestyle.

2nd Mar 2015, 11:14
Earl... How big was your investment to get it all going? Those panels aren't cheap.

2nd Mar 2015, 17:00
A huge number of places up here are going 'Off Grid', cottages and weekend places especially.

The cost reduction and power generation improvement over the last decade has been second only to that of PCs.

Despite the cold up here, we do benefit from over 2,200 hrs of bright sunshine p.a. Most places seem to manage with around 10' x 10' of solar panels and 2~6 deep cycle marine batteries. Year-round places seem to pop in a 2-5kW gen-set for the overcast days of January or to provide a top-up.

N.B. This is only for lighting and elec appliances, heating in -51c still requires propane gas or a trusty x million btu woodstove(!)

(CDN$10k will get you an A1 set-up.)

2nd Mar 2015, 18:58
Most places seem to manage with around 10' x 10' of solar panels and 2~6 deep cycle marine batteries.
What are those figures in terms of Watts for the array and Amp-hours for the battery bank?

2nd Mar 2015, 19:06
What voltage do solar panels produce? Can they be connected to give higher voltages?

Do you use the electricity at the supplied voltage? - or do you use an inverter to produce higher voltages?

2nd Mar 2015, 19:49
According to the DEF STAN, very strong Mediterranean sunlight is 1156 watts/sq. metre.

Now let's assume a 16% efficiency over the life and no cloudy days and 12 hour days over the year, that's about 3kwH/metre/day - at best.

Now let's allow for 50% cloud cover and we are down to 1.5kwH/metre - at best.......

How much a metre is the silicon and the controller and inverter etc?

2nd Mar 2015, 20:04
I lived without the grid from 1984 until 2004.

Sure no air-con but fans work just fine. Wood stove for heating the house and the water.

And yet non-believers still say it cant be done.:ugh:

These days I make a living installing for others.

Check out


It's got all you need to know.

Panels have never been cheaper. They used to sell for $10/ Watt
Now $1.58 and this is for good quality gear. You can buy rubbish for under $1

2nd Mar 2015, 20:04
What voltage do solar panels produce? Can they be connected to give higher voltages?It varries so you tend to talk about the voltage of the battery bank (12V, 24V, etc). A typical panel for a 12V system actually has an optimum operating voltage of around 17V-19V.

Connecting 2 like panels (2 x 100W 12V panels) in parallel will maintain the same voltage but double the output power (200W at 12V) whereas connecting them in series will double their voltage whilst maintaining the original power (100W at 24V).

Do you use the electricity at the supplied voltage?

As stated above the voltage referred to when discussing panels is the voltage of the battery bank whereas the actual output voltage of the panels is actually higher. A solar regulator is used to take the panel voltage and feed the batteries with the correct voltage required for the state of charge - at a low state of charge the controller will feed a 12V battery more than 14V. As the battery nears full charge the supplied charge voltage will drop. A fully charged 12V battery has a voltage nearer to 13V and will actually be less than 50% charged at 12V.

A 12V battery bank can be used to feed 12V equipment.

or do you use an inverter to produce higher voltages?
You can also use an inverter to produce higher voltages when required, but losses and power consumption mean that you couldn't draw too many amps for very long unless you had a large battery bank (in terms of AmpHours) or you would flatten your batteries and very probably damage them if they were drained too low (below 10V).

Hope this answers your questions.

2nd Mar 2015, 20:30
Hope this answers your questions.
Yes, thanks - it seems logical (and as expected - though I've never dabbled with solar panels before).

I am aware of the losses associated with converters - but I wondered if there was sufficient excess to make conversion worthwhile.


galaxy flyer
2nd Mar 2015, 21:50
A friend of mine here installed panels on his two-story house, about 2200 sq feet on two floors. By regulation all the power is feed into the grid but it works out that he produces as much as he uses averaged over a year.


2nd Mar 2015, 23:09
Yes it can be done, but the fundamentals stay the same, regardless of small (residential) systems to large ones. Those fundamentals are how much do you want to spend versus how much you want to sacrifice.

I have this same argument when I was doing some research last year, actually in regards to solar thermal (100 MW) stuff. In any system there is buffering, a lot of that with the grid takes place behind the scenes to give us power, when we want it, at a probability of failure of 1 in a large number.

Now a lot of so called urban systems where they say they are self sufficient, they really arn't, because they still have a grid line. In the case of outback stations, that nice little 8 kVA genset.

Yes you can spend more money, and have more panels/turbines/ batteries to decrease the probability of not having power due to local weather.

But in essence when you go properly "Off grid" that is no grid back up or genset then your accepting the probability of not having power in direct relation to how much you want to spend.

Note in some cases, yes we need gas or wood etc. Is that grid gas?

Now as with all these things, they are warm and fuzzy, and work all cute in small numbers, but there is the law of unintended consequences when considering urban environments an millions of residences.

3rd Mar 2015, 01:21
It can be done but its not easy.
You have to measure everything with a kilowatt meter.
This meter can be bought on ebay less than 20 usd.
Energy efficient things have to be bought.
Lights LED not CFL or normal bulbs,
A 60 watt light bulb in LED pulls 9 watts, , last 20 years they claim also.
Energy star refrigerator.
Learn to use propane instead of the microwave.
Cook with propane stove.
Use propane hot water heater, instant on heat is the best.
But has to be mounted outside the home.
Dry your clothes like our parents did on clothes line after washing in machine.
Desktop computers pull about 120 watts, get laptop new model.
My Laptop and router uses about 40 watts combined.
TV get LED model they use hardly any electric, 32 inch LG here about 30 watts.
My costs to date,
12 Panels off ebay 120 watt each 1,440 usd.
Chinese made and free shipping.
Dont fall for the made in usa ones, most solar companies bankrupt here, so warranty no good anyway.
Used them for over 3 years work good last long time ha ha.
Charge controllers 60 amps, have 2 morningstar ones, company 140 usd each.
Good for equalizing battery s also, will take them to 15.3 volts.
Chinese made one MPPT will only go to 13.6 volts you need more to fully charge the batts.
Batteries, I use golf cart ones.
Have 12-6 volt ones crossed wired to make 12 volts installed in 2 banks to the charge controllers.
Costs about 1500 usd.
They claim these Trojan 105 batts will last 10 years if you only take them down to 50 percent level.
Hopefully by then they have better storage ones.
Wiring is a big issue.
DC volts drop with distance on wiring runs.
Don't skimp on this cost will make system useless.
Cost 500 USD,
I used whats called unitrack to mount my panels and elevate them from the workshop roof,
Costs more than 100 usd
for all mounting hardware the cable from workshop to main breaker in house about 200 usd.
The Invertors expensive
I use modified sine wave for whole house except refrigerator.
5000 watt MSW cost 360 usd., 2/0 wire for this one.
Never pull more than 900 watts unless using power tools or air compressor.
True sine wave for refrigerator cost 300 usd.
Many in the solar sites say MSW is ok for refrigerator, maybe so.
I did run it like this for 6 months and no issues,
But changed just in case,
Heat is with propane and house is very warm.
Yes I did spend a lot of money but it was like a hobby, and I like sticking it to the electric company.
This also done over a 2 year period.
Not all at once.
I would sit reserve for my job and no flights constantly researching this.
Kind of proud no electric bill forever, now the electric company says we can give you power, say don't want don't need and get off my property,

3rd Mar 2015, 01:54
With what i spent many years return on this investment.
When I retire will help me most.
My grand kids will enjoy many years later.
I am not a tree hugging environmentalist one.
Still change the oil in my trucks and Harley pouring where I Don't want the grass to grow.
When I needed the electric company they was not there for me
Many excuses.
Like you don't have address or home yet.
Well was told you cant have address without home
Even offered to pay large deposit for this.
Useless government here in USA.
Read Kock brothers heavily invested in SC and Florida utilities so we are the most non friendly AE states in the USA.

3rd Mar 2015, 08:23
A friend went for the "free" living using a water turbine in a nearby creek which could only manage a few lights and a small fridge. He did it for about 2 years before the wife cracked the sh!ts trying to raise 2 children in those conditions so they moved back into town.

You would think a solar standard (say 12V) for domestic appliances would have evolved by now.

One of our neighbours installed a $10k PV system, and seeing they seem to go to sleep at sunset you'd think they are trying to get rich on the savings rather than have a life.

In my situation I found taking the basic steps to improve electrical efficiency has actually worked and my bills have not risen that much anyway. I imagine it would really suck if my welder ran out of juice and there was nothing I could do about it.

3rd Mar 2015, 13:30
I did a study on renewable energy for remote locations as part of my physics degree. Efficiency is the starting point. The rest of the process is not viable until this is done.
Availability of the resources (solar, wind, etc) is of course necessary, but of almost equal importance is the longest period without the resource (e.g. days of calm/fog, etc). The latter data is often not available or has to be estimated 'by hand'. Fortunately there is much raw data available in .csv files in the last couple of years, so by hand is now 'by custom excel spreadsheet', which is a lot quicker if you can write VisualBasic.

12V setups are common on yachts and RVs; adapting one of these is your best bet. One of the problems for domestic appliances is that peak power is not published, but this vital for optimal electrical system design. A smart meter does the trick, but you have to buy or borrow the appliance.

3rd Mar 2015, 14:30
Why stick with 12 volts? Why not series up panels and batteries and run at say, 48 volts? Low enough voltage to reduce the chances of a nasty shock and one quarter of the current for the same load power, so much less loss in the cables - for the same size cable, 1/16 of the loss. Should be a cheaper invertor, too, since the transformer will need thinner wire and the switching transistors are smaller - or you need fewer of them, depending which way it's designed.

For things running off 12volts, a 90 or 95% switching regulator will do a good job.

3rd Mar 2015, 14:40
You are of course correct Radeng, I was simply answering the question asked. The commercial availability and pricing of system components depends on sales volume more than the engineering. These factors are changing rapidly. Wire run distances are also pretty important. Whether one goes for roof-mount or a better resource at some distance (wind turbine on mast, solar tracker) is a big decision.
There's also a pretty big decision over turnkey or user-monitored/maintained. Quite a lot of people think amplifiers make amps.;)

Personally, I shall probably go with 24V or 48V with my next property.

3rd Mar 2015, 18:18
I could do with you here. Currently paying 30p per Kw/Hr. Some properties do have photovoltaic panels but the grid on island can't upload this energy.

4th Mar 2015, 01:04
Thats the one mistake I made is doing the 12 volt system,
24 would have been better and the one posted correct here the first step to making this work is cutting demand, using more energy efficient products, lights etc.
Doing some research now to see if its possible to cross wire my panels for 24.
Batts easy to do, panels not so sure.
All my panels are each individually wired and to own breaker.
Its a hobby and a learning experience, had fun doing it and far from finished.
Everything is like normal home here except for the Air Con in the summer.
For now no electric bills makes me smile.
This works.

4th Mar 2015, 02:50
Earl, re-wiring the panels is easy. Just put each pair in series.

4th Mar 2015, 09:57
Is it that easy, lantern? I suspect that you can series the PV cells, but then you need a charge controller designed for the higher voltage, and I do not know if they can necessarily be easily connected in series. It could be better to have multiple 12 volt batteries, each with its own PV panel and controller, and then put the batteries in series - each controller will see its designed load then.

4th Mar 2015, 10:14
The renewable industry is not strong in most markets at the moment. Commercial companies charge a lot for design & installation, but won't take the time to sit down with the client and discuss lifestyle & efficiency first, so it is marginal whether these projects are economically viable. The people who are already living efficiently are often a bit kookie for mainstream taste, and too many are not qualified/experienced in engineering/science. As a result, the options are either expensive, or appear homebrew wacko.
Add in the planning restrictions of ridiculously conservative local government, building code supervisors and drafters who ignore what renewables can do and won't licence them, and a construction industry that just wants you to shut up and buy more of their 'boxes', and renewables get suppressed.

4th Mar 2015, 10:42
I suspect that the renewable industry is being 'sold' by salespeople operating on, mainly, commission, so they are motivated by selling whatever rather than considering the suitability of the product.

As a comparison, during a period of unemployment in the 1980s, I was tempted to become a self-employed 'heating control' salesman (franchised of course).

As an engineer, I could see that the product was sound (and sensible) but the prices were astronomical for what was, in simplicity, a sophisticated thermostat.

The savings being promised would only have been achievable for an extremely inefficient system. The claims being promoted were that everyone could achieve significant savings - however, the high cost of the equipment would require a long period before the costs were covered.

I declined the opportunity, partly because it involved significant financial investment by me (purchasing the franchise), and partly because, being commission only, it depended on me selling overpriced equipment to gullible customers.

5th Mar 2015, 09:06
Nah, what you really need is one of these!


BBC News - Wind turbines take to the skies to seek out more power (http://www.bbc.co.uk/news/business-31300982)

7th Mar 2015, 02:42
Yes Fox bannaa you are correct as many others here.
You have to measure your needs, but you don't need a firm to do this.
Adds more useless costs.
Many solar web sites have calculator that can do this for you.
Even if you don't have a kill o watt meter and break it down by lights and appliance.
They can take your electric bill and compute system required for you.
Its a different lifestyle.
Takes planning but not 3rd world cuts or like back woods living.
Only things cut here is Air Con and electric clothes dryer.
These I can manage as no electric bill every month makes me smile.

7th Mar 2015, 20:35
Had a guy round last week to fit our gas hob, some'at to do with Corgi registered.

He works for an "Eco" firm, sprouted out a load of maths, which sounded fab, but never actually worked out if I'd be saving any money or not. And who exactly would own my roof ? ( and where do they store all this energy when no-one needs it ?)

Having said all that, we have lot's of sunshine down here in Cornwall, if you leave your hosepipe rolled out in your garden, the water can be scalding. Seems a bit of a waste.

Had a chat to the bloke who run's the Eden centre a couple o weeks ago, he reckons it costs 500,000 to heat the bubbles all year. He was on about digging a deep hole to try and capture the earths heat.

7th Mar 2015, 21:34
Radeng, you are correct about the controller having to be the correct voltage.

The best controllers will do different voltages, 12, 24, & 48

Plasmatronics - Solar Power Regulators (http://www.plasmatronics.com.au/)

Re many batteries in parallel. Most certainly not a good idea.


7th Mar 2015, 22:02
I'll admit I've not looked deeply into solar. Firstly, they all get cold feet when I tell them that unless they can guarantee the radiated noise level between 50kHz and 500MHz at a distance of 3 metres must be 10dB below ITU-R Rec. P372-11 quiet rural noise levels for the whole installation, I am not interested, and they also say I have too many trees and not enough visible sky....

8th Mar 2015, 04:15
Radeng I am not sure what radiated noise levels you talk about here.
Yes near the batts and charging controllers you can hear it,
If you use a radio near there you will hear background noise.
Try connecting this source away from the charge controllers.
This works here.
Less than 8 feet works.
In my shop if i recharge my craftsman power tools i get interference noise on my radio and tv there.
Bit in the house none, I think its distance problem.
Morning stars contollers all multiple voltage.
and morning star has dip switch to help with radio interference,
Used Chinese MPTT learned my lesson .
They make good panels but aside from that all trash ones.

8th Mar 2015, 08:54

there's a heap of difference between the level of noise that does not interfere with a broadcast radio or TV and the level that totally wipes out ham radio - especially when one is living in a rural location that is fairly quiet from a radio noise viewpoint. The ham radio needs noise up to at least one thousandth of that level which broadcast radio can stand....

9th Mar 2015, 03:10
Ok Radeng.
Different frequency and if you say it interferes you are much more knowledgeable about this than me.
My father did the ham radio hobby, but we had normal electric when i was growing up.
He seemed to enjoy, pissed my mother off though up late hours talking to ones all over the world.
We all have out hobbies, cant say his one was bad.
Anything you enjoy is a good thing.

John Hill
9th Mar 2015, 05:09
I have experienced a few places with home grown power, farms and isolated hotels etc.

There is no doubt that nothing beats a small hydro for trouble free power in such locations.

Interesting page, http://pukeariki.com/Learning-Research/Taranaki-Research-Centre/Taranaki-Stories/Taranaki-Story/id/528/title/smart-drive-success-ecoinnovation

9th Mar 2015, 08:50
>There is no doubt that nothing beats a small hydro for trouble free power in such locations.<

Very true, John - IF you have a suitable water supply that will continue running through the dryer part of the year. A number of places in the early 1900s had their own steam plant to produce electricity, which can be effective. Some of the 'behind the lines' resistance radio operators in WW2 had small steam power plants with a Stuart steam engine for charging batteries: that had the advantage of being much quieter than a diesel or petrol engine, and fuel was easier to get. Plus they charged the batteries rather faster than could be done with a bicycle type generator.