Off grid

[robert8n]

I'm done with contracts and bills, I've had so many bad experiences with every utility provider during my 11 years of being a house owner in France that I decided it would be less stressful and closer to my ideal of my French retreat if I can somehow quit all of them. Well that day is approaching. I ended the SAUR contract a few years ago, instead of FT I use a PAYG phone for calls and email, or surf the net at McDonalds, get gas in a bottle from the garage, and heat the place with wood from the land. Next up is electricity. Although I've lived without it, I do want electricity. For now I have a petrol generator that was a gift, but I'm planning to put up a turbine and some solar panels. I can get both at a reasonable price as I work in China. My question is just about wiring. As the existing wiring goes to the junction box, which is fed by the EDF supply cable. What would one normally do to supply the box with the home produced power? The EDF cable is no longer live as they put a 'breaker' on it when cutting off the supply, so theoretically I could just take that out of the box and replace it with the cable from my home supply.

[Gluestick]

It's a nice idea, Robert, however, the ability to live reasonably with a minimum of modern conveniences does require a constant source of electricity I would think.

To respond to your questions, connecting alternative and renewable electricity sources to the existing house main is reasonably simple.

Most PV arrays produce around 25 to 40 Volts Direct Current (DC). Each cell produces an EMF (Electro Motive Force) in region of 0.5 Volts: these are usually connected into modules: and the subsequent modules connected as an array.

House mains demand 230 Volts AC (Alternating Current) delivered at 50 Hz (Frequency).

Solar power from PVs are then fed into an Inverter, which converts the supplied electricity into AC at the required voltage and frequency.

It is usual to also use an assembly of 12 -24 volt Lead Acid Batteries, as a reserve: these are charged when the sun is shining and the required load zero or negligible: and discharged on demand.

Wind-power turbines are usually Alternators used to charge battery banks, via electronic regulators and control systems.

You already possess a generator: perhaps the way you should be looking is an integrated solution using wind, Solar PV and the generator.

Decent robust generators come with self-starters and automatic switchover options.

Perhaps firstly, however, consider evaluating the deal where you sell spare electricity capacity to EDF's grid and this offsets your own use.

The capital cost of a decent solar array of PVs is not small: be warned!

Additionally

[robert8n]

Thanks. I'll be setting up the turbine next year and the panels probably the year after. I won't be selling back to EDF. As I said, my aim is to have zero contact, and zero contracts with these large entities.

Really, I specifically want to know about wiring the source, whether it be from the batteries or the generator to the central unit in the house.

I wonder if anyone has done this, or knows of a good website.

[Gluestick]

Usually, the turbine power output is fed to a regulator/control box and then an inverter; and thereafter into the batteries. (The inverter is necessary since most turbines use an alternator: which generates AC current.). Thereafter into the battery bank.

The PV array similarly is fed into a control box and then voltage dropped and thereafter fed into the battery bank.

Output from the battery bank goes into another inverter (since the battery current is DC and 12 volt) and shifted up by the inverter to 230 volts 50 Hz Ac.

This is fed straight into the house supply.

You would also require further electronics control systems to disconnect the battery bank, when the voltage dropped to, probably circa 9 volts: to continue operation would impair the batteries and the house supply would rapidly drop in supply potential.

Thus you would need, perhaps the additional control systems to switch the generator on and re-charge the battery bank; or supply 230 volts AC to the house.Or even divide the generator's supply between the two requirements.

Most systems switch over automatically to mains supply if/when the battery bank potential falls past a set limit.

Websites in profusion: try Googling!

Unless your battery is flat!

[:D]

[robert8n]

Hehe, no I'm not dependent on batteries yet. But it's true, part of doing this is being prepared to live less conveniently than before, indeed one may suddenly be thrown from the 2000's the 1700's at a click.

Of course I have Googled - the profusion is the problem, haven't found a good one yet.

So, when feeding it into the central home unit, from the battery inverter, I would just disconnect the EDF cable supply and connect the home supply cable right?

Thus, when the power is there, the lights and sockets will function normally.

[crossy67]

You need to be aware of the life expectancy of deep cycle batteries too and the replacement costs.

[Théière]

Keep a look out for a true sign wave inverter as apposed to the cheap versions which could cause problems with some equipment.

[Gluestick]

[quote user="robert8n"]

So, when feeding it into the central home unit, from the battery inverter, I would just disconnect the EDF cable supply and connect the home supply cable right?

Thus, when the power is there, the lights and sockets will function normally.[/quote]

Basically, yes: with the provision (As I have already suggested) of a voltage controller which chops the battery bank out of circuit, when and if the battery voltage droops too far. Since, to continue draining the batteries past a certain minimum point would start to destroy the cells.

For myself, a logical starting point would be to carefully calculate the probable average load you expect to need: and to then assess the size of the battery bank necessary; the Amp/Hours required (Allowing for losses in the inverter - nothing's for nothing in this spavined old World!): and the charge rate necessary to bring the battery bank to full charge once more.

I would suggest that the hard one is to estimate the likely power production from both turbine and PV array in average conditions.

Few wind turbines to date seem to have actually delivered the Blue Sky expectations boasted by their manufacturers!

As with all such projects, it's the system integration which is the hardest bit: and this is where it seems, the present crop of sellers are making hay. The capital cost of the control modules is very high: PVs from China are now reasonably cheap and the price falls constantly as production volumes rise: same with all technology.

It is the logic modules which knit the whole thing together.

Your project has yet another additional component: the IC powered generator. Now, this could be used to recharge the battery bank, and/or supply current to the inverter, when wind and sun are low and the battery bank needs charging.

Thus you have a number of interactive and co-dependent functions to consider.

Really needs the assistance of a capable electronics engineer, who enjoys significant knowledge of solid state logic circuits and mains supply.

Alternatively, you could work on the basis of simple two pole switches: however, this would mean dashing around throwing switches as required.

Building in some level of system autonomy would seem like a good design philosophy to me.

[Etoile]

I think it is possible to make this complicated. Were I going off-grid, and I will one day, I would look at going all low-voltage.

Lighting can be straight into 12v halogen downlighters, (with none of those unreliable transformers.) TV's and computers are all available for low voltage nowadays anyway; just walk into your local motorhome/caravan store and see what is available. Cooking would be by bottles gas as stated, with water heated probably by a combination of gas and the sun.

I have even considered installing a 12v lighting system in our present house run from a wind generator supporting a couple of lead-acid batteries. The whole setup could run alongside the mains system using seperate cables. When it was flat we would simply revert to the mains.

[Gluestick]

[quote user="Etoile"]I think it is possible to make this complicated. Were I going off-grid, and I will one day, I would look at going all low-voltage.

Lighting can be straight into 12v halogen downlighters, (with none of those unreliable transformers.) TV's and computers are all available for low voltage nowadays anyway; just walk into your local motorhome/caravan store and see what is available. Cooking would be by bottles gas as stated, with water heated probably by a combination of gas and the sun.

I have even considered installing a 12v lighting system in our present house run from a wind generator supporting a couple of lead-acid batteries. The whole setup could run alongside the mains system using seperate cables. When it was flat we would simply revert to the mains.[/quote]

Wiring costs for a whole-of-house 12 volts system would prove interesting!

Often forgotten is dear old Ohm's law.

[quote]When it was flat we would simply revert to the mains[/quote]

Battery banks are not cheap: particularly such as Deep Cycle(Deep Discharge), invariably Gel type.

Whilst it is not a bon idée to discharge too far (past circa 80% of full capacity), repeat "Using until flat" would destroy the battery in short term.

Of course, one could always employ this technology............

Far simpler too!

[:D]

[IMG]http://i461.photobucket.com/albums/qq332/PercyPee/OilLamp.jpg[/IMG]

[robert8n]

Yes, I have several oil lamps. In fact, as I said earlier I lived for one summer (yes I know, easier than winter) entirely without electricity and it was probably the best summer I've spent at chez moi. The only real problems were the fridge, which can be replaced with a propane version; and the inability to use some power tools, which I could now use the generator for.

The lack of TV and internet had us raiding the home library, and we played games together at night as a family which was just great.

I agree with Etoile that this can be made to appear so technical and expensive that you just want to give up and go back to EDF, cap in hand. But I will not.

My starting point will be like that summer - assume I have zero electricity, and take it from there. Anything I can generate and afford to buy the equipment for will be one step towards my goal.

[woolybanana]

All of this seems a heck of a lot of effort and unnecessary hard work to avoid the electricity or gas companies. Presumably, if you family grew and grew because of the lack of anything else to do in the evenings, when the books have all been read and the games played, then you would also refuse the family allowances proferred by the generous hand of the State? You can't have it both ways (NO!)

[Gluestick]

[quote]I agree with Etoile that this can be made to appear so technical and

expensive that you just want to give up and go back to EDF, cap in hand.

But I will not.[/quote]

I disagree, Robert.

Yes it is complicated, perhaps, for those with little technical and engineering knowledge, experience and hands-on involvement.

As I've suggested twice or so, with all such projects it's the System Integration which is the hard bit. The bases are all there and freely available: it's the knitting together which is the main challenge.

That said, the power of the internet is awesome: and there are literally dozens of websites dedicated to self-sufficiency, Green technology, renewable energy and so on. Even one US site which shows plans for a home-brewed Permanent Magnet alternator made from a Volvo brake disk assembly for a wind turbine!

Circuits for inverters too are ten a penny.

For example: See here:

Entitled "Living Off The Grid".

A reasonable starting point.

[:)]

[robert8n]

Yes, I've seen those DIY turbine jobs and they seem to work just fine. I had intended to do that that until I started looking here and found I could get what I wanted, ready made, of strong materials with guarantees, for a reasonable price.

[robert8n]

@ wooly. Can't have what both ways? - the hypothetical situation and hypothetical response to it that you've created?? LOL Thanks for the suggestion, but I'm done breeding and I don't take, and seek not to give to the state.