Navitron Renewable Energy and Sustainability Forum

WIND TURBINES => Wind Turbines and associated systems => Topic started by: Alternative on June 23, 2006, 05:40:36 PM



Title: Any Navitron wind turbine users in East Anglia?
Post by: Alternative on June 23, 2006, 05:40:36 PM
I'm interested in buying a 200 watt wind turbine and wonder if there are any existing users that would share their experiences. I have a low windspeed location in Suffolk and would welcome advice on whether to go for a 12 volt or 24 volt turbine to charge my large 12 volt battery bank.

I quite like the idea of using a 24 volt as it would have a lower cut-in speed and might be more productive for me, given that the maximum power will be reduced.


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Ian on June 23, 2006, 09:09:06 PM
If you have a low windspeed then you are limiting the power output from your generator. However, low (average) wind speed does not mean that the wind never blows strongly. When the wind does blow strongly you will get near or greater than rated generator output and you have to be able to handle it.

Similarly, low average wind speed probably means that there is a lot of time when the generator contributes zero power to the battery banks (even though the generator spins).

So, is it OK if the batteries do not get charged for, maybe, 3- 4 days at a time ? What are the implications ?

I would recommend that you go for a 24 volt model generator even though you have 12 v battery banks - but you MUST have a charge controller (diversion load controller) in place and also a dump load to handle the excess when the wind does blow strongly. Most batteries are best charged at about 10% of their rated maximum discharge capacity so the battery bank should be sized to cope with the maximum current the generator can output (200 watt at 24 v = about 10 amps; but sinking it into a 12 v bank means you should expect the current to be more like 20 amps when it is going flat out).

Agreed, a 24 v generator would start to supply a charge at a lower windspeed than the equivalently rated 12 v version.

I hope this helps.

Regards,
Ian


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: ATB on July 06, 2006, 12:15:41 AM
Hi
I'm in sufffolk as well.
I'm thinking of getting a 200w 24v turbine just to try to heat the central heating in my workshop.
One thing I will do is put it on the tallest pole i can get and stuff the planners. I can always get permision later if i get caught!!!!!!
As i'm out the way a bit, I'm hoping no one will notice it when its up!!!! ;D

I'm also worried about the low wind speed. but i think you are right to go with the 24v.
I was going to see how it went over the winter and then in the summer when i'm not needing it for heating tying it in to the grid maybe.

The other thing I'm thinking of is having a micro wind farm. 50 x 200w turbines (10kw) in the field out the back of my workshop! No need for planning permision if I keep them all below 4m. Tie them all into the grid and sit back and watch the pounds roll in!!! :P

Oh lord I can see the controversy in the East Anglian Daily Times now!!!! ;)

Maybe I should just try the one first!!!!!!!!

ATB


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Alternative on July 06, 2006, 10:50:29 AM
Thanks to you both for the informative and helpful replies. This has enabled me to make up my mind to go for the 24 volt version of the 200 watt turbine. Another factor is the impending availability of the small 250 watt Dutch grid-tie inverter which I believe Ivan is testing at the moment. He has mentioned that it should be suitable for use with the 24 volt turbine.

I will place the order for mine as soon as Navitron have their new stock in later this month. Look forward to comparing notes with ATB, also in Suffolk, with his micro wind farm!


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Wile.E on July 21, 2006, 07:24:06 PM
Hi Guys! Iam a newby to all this Wind Turbine stuff but very keen to learn!
I live in Cambridgeshire and I too want to install a wind turbine to power my outbuildings (initially). Have looked at 200W but would really like to provide more power so I can eventually go 'off grid' for the outbuildings and power the pump etc for the indorr swimming pool I am about to build. Dont yet know power requirement  for the 3/4 HP pump but expect it will be a lot more than 200W!!
Interested in how other like-minded people are setting-up and controlling their W Turbine systems: choice of W/T, battery size/capacity and quantity, connections, heat sink etc.

Look forward to hearing from you all!

Wile.E :)


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Ian on July 21, 2006, 09:47:48 PM
Wile.E,

1 horsepower is about 750 watts so 3/4 HP = 560 watts. However, a motor is usually rated at the work it can do and not the power it consumes. It depend on the motor efficiency as to how much power is consumed in order to deliver 3/4 HP of work.

So a fudge factor (efficiency) needs to be applied and on a small motor like this I would apply at least a 25% fudge rating which brings you back to 1 HP or 750 watts.

Note, also that this is a motor and therefore inductive. When running in a steady state it will consume about 1 HP of power but at start up it will be significantly more than this (between 3 - 10 times as much for a few cycles until the motor has started to turn and build up enough back EMF to restrict current flow). So at start up you should allow for, say 5 - 6 HP.

Most inverters will easily handle twice their rated capacity for short bursts so you should specify the inverter for, say, 2 or 3 kW. (You could try to get away with a smaller inverter than this but ultimately it will stress the motor and the inverter and lead to premature failure - even though it will appear to work when you try it).

I hope this helps.

Regards,
Ian


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Wile.E on July 21, 2006, 11:58:26 PM
Ian
What a star! Once again you have provided me with help and advice - thank you.

Based on what you have suggested I will need a 2-3 kW inverter but how do I now work back to identify the size of the W/Turbine that I will require to supply this power. Should I be charging batteries and then inverting and if so what AH rating or do you think I will need to power direct from the W/turbine? Sorry that I have so many questions but I am really keen to understand the power calculations etc. and start to use 'green energy'
As always any further help advice will be welcomed!

Thanks again

Wile.E


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: martin on July 22, 2006, 01:23:31 AM
not too difficult to work out! If I remember right, swimming pool pumps run 24/7, so if you're working on 750 watts, that'll be 18kwh per day - which is roughly twice the average family electricity consumption (which can normally be "balanced" by a 2.5kw turbine)- so for just that job, you'd be talking something like a 5kw turbine - probably best "grid tied" - less hassle if possible - otherwise a thumping great battery bank! - (very rough, rule of thumb job - obviously very dependant on siting of the turbine). If you're thinking of a "biggie", talk to your local planners first - 5kw turbines are kind of noticeable ! 8)
It really isn't practical to run the pump direct - it needs to run all the time, and the wind doesn't! :-\
It's doing these sorts of sums that brings home just how much energy we use! - that pool pump uses roughly twice as much as an average family - for everything! :-\


Title: Re: Any Navitron wind turbine users in East Anglia?
Post by: Ivan on July 30, 2006, 01:59:13 AM
We are currently doing a promotion on the 200W 24v wind turbine - 150 for the unit that sits on top of the tower - ie alternator, blades and tail. We are doing this to try to underline that wind power does not have to be expensive. You will still need to find tower, guylines, rectifier unit and batteries etc, but many people like to source these items themselves.

The 200W unit is a great low-cost way to investigate wind power, and most people do not bother with planning permission for wind turbines under 2kW (although in many applications they should do in theory). In most cases, this is not a problem, but where planners are sharp-eyed, you can normally avoid the issue by reducing the height below 4m - not ideal for wind turbines, but they still work (I have a 2kW machine operating at 4m height)

Ivan