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windtinker
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Joined: 16/01/2012
Location: New Zealand
Posts: 38

Posted: 03:46pm 06 Oct 2012

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Hi I've almost finished building a windmill(36volt) and was thinking about connecting it to the house wiring. I was wondering what is involved to connect to the grid and average prices for like inverter,sparky charges etc.
If you know of parts in NZ would be better.

Cheers for the help

davef
Guru

Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 08:52pm 06 Oct 2012

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Do you know what you will get paid for feeding power back into the NZ grid?

How much EXCESS power are you generating?

davef

windtinker
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Joined: 16/01/2012
Location: New Zealand
Posts: 38

Posted: 11:16am 07 Oct 2012

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Hi Davef
Should be 1Kw(guesstimate) , Last time I rang up the power company it was 8cents/kw. We pay 25cents/kw

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 02:56pm 07 Oct 2012

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So in reality you might generate 1-2kwh per day (8-16 cents worth) do you think its worth feeding to the grid??

Why 36 volt? its a strange voltage with most systems on the market (12, 24, 48v)

My advice to you would be forget the grid for now and just charge some batteries and use the power as DC, so you can measure what your windmill makes on a daily average over a course of 12 months, then see if its worth the investment of an suitable GTI and all the expence of doing the grid connect.

Im tipping without additional solar the mill would not be worth the connection, and even to the point your batteries might suffer sulphation due to undercharged batteries for long periods of time. (the batteries should be FULLY recharged within 24 hours of discharge or they will suffer from sulphation)

Sometimes it just works

windtinker
Newbie

Joined: 16/01/2012
Location: New Zealand
Posts: 38

Posted: 01:51pm 08 Oct 2012

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Hi Downwind

I've been thinking wiring it up to a second hot-water element, and pay the plumber for the connection to the hot water might be the way to go by what your saying.
Any one can wire low voltage?
What would be the minimum for a grid connect 2kw, we average 5m/s wind here?
How much solar panels to keep the battery from sulphation(with 1kw inverter)?

Cheers

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 04:18pm 08 Oct 2012

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In many ways you need to get the mill up and see what it will make, as often what you think it will do and what it actually do are 2 very different things.

Its worth logging the mill i think, as this will prove what power the mill will make over 24 a hour period.
Watching some figures bounce around with the eye wont tell you a darn thing as the eye only sees the big numbers and not the true average to know what is produced over a time period.

Once you have some data then you can decide what is cost effective to use the power for.

Hot water is not as simple as you think, due to the high wattage most elements are, this then causes the element to drain the batteries too quickly, or overloads the mill to the point it wont get out of stall.

[quote] What would be the minimum for a grid connect 2kw, we average 5m/s wind here?
[/quote]

Thats like asking how fast is a race horse so you know which horse to place a bet on?

[quote] How much solar panels to keep the battery from sulphation(with 1kw inverter)? [/quote]

Again its a open ended question, because it depends on how the system is setup to operate.
For example if the inverter is off line till the battery is fully charged then any small panel will do, its just a matter of how long it will take to charge the battery before the inverter is switched on, this will depend on battery size, solar hours, and panel size.

Then you have to workout what panel or string of panels will give you the 36 volt range you picked. (its a strange choice of voltage for todays standards)

You might be better off thinking about using the power to run the lights in your house to start with.
The average house has a light circuit that is easy to route to an inverter with a switch to swap back to mains.

This allows you to store power and charge the battery, then cycle the battery at night to use the power.
It also allows you to adjust the loading (what wattage globes are used and how many lights on)to work out what power you have to work with.
The worst case is it runs the battery down and the lights go out, till you switch back to mains.

Its a hard thing working out what to do with windmill power if you dont have another system in use to add the mill power too.
A windmill is not a very reliable method of producing energy, some days there will be bucket loads, and then weeks of bugger all.

You might be lucky and have a better average, but dont over rate what you think you expect to generate or it will cost you heaps in setup for almost no return.

Windmills can be often like owning a poodle, some inspire to have them, might be nice to look at, costed a small fortune to get and maintain, but next to useless 90% of the time, but was a great idea at the time. (im sure a few of the opposite sex fits that bill too)

Sometimes it just works

windtinker
Newbie

Joined: 16/01/2012
Location: New Zealand
Posts: 38

Posted: 07:58pm 19 Oct 2012

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Thanks for the replie. I've got a uncle that is living off grid, and in the past hes inquired about a windmill, might sell it to him.

Cheers

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