450W Turbine mounted on roof

Gloves · October 2010

Hi, I would like to introduce myself. I’m Gloves a green-energy amateur hobbyist
with less than a basic understanding of electrics. Never the less I have setup a
450W, 52 Diameter, 10-blade turbine on my roof that charges 2 T-105 batteries and
inverts to a 110V outlet (off-grid).

I have various questions about adding to, upgrading and monitoring the system
that I haven’t found answers to elsewhere. Maybe you guys can help some. I read
some of your posts and they seem to range from medium-size 1000W to hard-core
10KW off-grid 100’ tower systems!!! (Completely amazing!)

I live in California, am I still allowed to join?

BB. · October 2010

Re: 450W Turbine mounted on roof

Welcome aboard. The more the merrier!

What are your questions? We may be able to answer a few of them and point you elsewhere for other answers.

-Bill

dwh · October 2010

Re: 450W Turbine mounted on roof

Neat. Welcome. Who made your turbine?

The only Californians allowed are the fruits and nuts.

Gloves · October 2010

Re: 450W Turbine mounted on roof

dwh, I'm not a fruit. Defiantly a nut.

(see site link below, it explains the setup)

I started a web page on my build. It's far from finished.
http://www.glovesandclover.com/tutorials/wind-power/index.html

I live in "Sunny California" not "Windy California" where it's always sunny but not
always windy even though there is often wind, it seems it takes a wind storm to
charge the 450 Ah batteries even just a little bit.

So, I would like to add a single 120W solar panel to the mix.

Electrical QUESTION:
Can I add a 120W solar panel (6A i think)?
This is the one i want:
http://www.ul-solar.com/ProductDetails.asp?ProductCode=STP120P-SPE&CartID=1

Can I add it to the same wires that go into my charge controller? (dumb question: Do solar panels need a rectifier?)

I have a feeling that this will help charge the batteries much faster as I get a solid chunk of the day with consistent light where I get about 3 hours of moderate wind daily.

Thanks in advance.

niel · October 2010

Re: 450W Turbine mounted on roof

2 observations i made from your pic.
1> mounting a turbine to a house is shaky to do. literally. the vibrations aren't good for a home even if you find you can tolerate them.
2> the turbine needs to be about 20 or 30ft above surrounding obstacles to catch significant wind and avoid eddy currents in the air that can be detrimental to a turbines lifespan.
now having that many blades is not normally done for a turbine and i have long since forgotten the reasons for not using that many, but i believe it may involve the tip speed and thus the proper gearing of speed to the generator/alternator. don't quote me though as i'm unsure.

as to your concern of adding a pv. go ahead, but run it to a good charge controller and then to the battery. try to get one that accomodates a remote battery temperature sensor, aim your pv generally south with an elevation angle of at least your latitude, and use wires of the proper size with fusing preferably at the battery.

dwh · October 2010

Re: 450W Turbine mounted on roof

Gloves wrote: »

I live in "Sunny California" not "Windy California" where it's always sunny but not always windy even though there is often wind, it seems it takes a wind storm to charge the 450 Ah batteries even just a little bit.

Aye, and there's the rub. The general rule of thumb is that for small wind power to make truly useful amounts of power, you need an minimum *average* wind speed of 10mph. If you had that, you'd probably be buying Chap-Stick by the case.

Unfortunately, most people don't know that and so they end up finding out the hard way.

Can I add it to the same wires that go into my charge controller? (dumb question: Do solar panels need a rectifier?)

No and no.

You can't tie two different voltage/amperage/whatever generating systems into the same charge controller. You need one for each type of system. But you can hook up multiple charge controllers to the same battery bank. They'll each do their job independently.

Solar panels don't need a rectifier because they put out DC not AC.

I have a feeling that this will help charge the batteries much faster as I get a solid chunk of the day with consistent light where I get about 3 hours of moderate wind daily.

Yea it will. Just keep in mind that for a fixed mount you'll only get 4-6 hours/day on average of "good sun" - i.e., when the PV module is putting out full power.

Gloves · October 2010

Re: 450W Turbine mounted on roof

you guys...
THIS IS WHY I JOINED!!! this is GR8 Advice!

Right now i'm finding out that I had consistent wind 10-15 mph in summer and
now nothing!!! :grr How was i supposed to know the wind was seasonal? I got
to admit, if for no other reason, it make my house look cooler than all the other
houses on the block... Until some jealous person complains the government
that I don't have a permit that the city wouldn't hand out anyhow...

25mph is considered a wind-storm here (supposed to be ~35) and the turbine
seems to take 25+ with non problem. I hope my house isn't going to fall apart,
under no load you can't tell it's there. Under load, it sounds like a leaf blower a
block away. What's up with that?

I would have put the turbine higher, but there's another city ordinance that limits
the height of towers & taller towers = harder to keep stable. Also, nothing I can
do about the STUPID tree next door. Luckily the wind only goes in 2 directions
(from front to back and back to front, tree is on the side)

Everyone knows that wind is much cooler than solar, but I'm going to add the
solar option.

ADDING SOLAR, Please give me your opinion on my shopping cart:
1 Qty: This solar pannel
1 Qty: This Charge Controller (I don't need to monitor batt temp, just 1 solar panel and 2 well ventilated batteries. I don't draw or charge more than 7.5 amps)
+ mounting brackets

Love the feedback.

JESSICA · October 2010

Re: 450W Turbine mounted on roof

Gloves wrote: »

... Also, nothing I can
do about the STUPID tree next door...

Trees are not stupid; We are.

I have more than 20 trees in my property, and NONE of them interfere with my pv system. I do have to trim some of them once in a while, yes, but that is part of the deal.
Maybe you can talk to your neighbor (if he is not of the stupid kind), and he may agree to trim the tree just a little bit.

Now my stupid opinion: I think that controller is too small. Believe me, in the future you will want to add more panels, and then you will have to buy another controller. It would be better if you buy a bigger one now. (If possible, buy an mppt controller.)

russ · October 2010

Re: 450W Turbine mounted on roof

No problem adding anything! I will be very surprised if your 'sounds like a leaf blower' thingy on top the house does not shake everything apart soon. Possibly doing damage to the solar PV system that should work as it collapses.

Wind turbines should never be mounted on a structure other than a tower.

Most people have no idea how strong a wind is until the have a meter to watch. Don't be fooled by what people say. Even 10 mph wind areas (on an annual basis) are not common.

The 25 mph variety that these small units are normally rated at is a bad joke.

Your show piece is going to turn into something for the neighbors to laugh at and about.

keyturbocars · October 2010

Re: 450W Turbine mounted on roof

Gloves, Your wind turbine looks cool. It will probably be mostly just for looks. Even if you had good, consistent wind in your area, those type of wind turbines (based on a car alternator) do not seem to produce much useful power unless you have very high winds... unreasonably high winds. I've seen places advertise those type of wind turbines as 1500w.... 1600w... even 2000w. The joke is that you have to have winds like 80+mph to get those outputs. I doubt any Delco sized alternator would reliably produce that kind of power even if someone could live in such a windy place. Not that anyone would really WANT to live in such a windy place - even if it did exist!

In any case, most of these wind turbines are more for fun and experimentation than they are for generating really useful power. It's more for hobby. Nothing wrong with that. They can generate some power, but just not enough to be useful for most people.

JESSICA · October 2010

Re: 450W Turbine mounted on roof

russ wrote: »

Wind turbines should never be mounted on a structure other than a tower.

russ:

Not even on solid (5 inches thick) concrete? Even if the turbine is a very small one, like the 200 watts Chinook?

BB. · October 2010

Re: 450W Turbine mounted on roof

It is a combination of factors that make roof mounts problematic...

Turbine should be mounted 30+ feet above the home/obstructions and 60+ feet above the ground for clean air flow.
Turbines, turbine mounts, blades/hubs, and towers do fail--Not a great idea to mount a couple of hundred pounds of metal right above a residence/where people congregate.
Vibration and "cogging" (from alternator), etc. all are transmitted by pole/wiring to the structure. Stresses can cause structure to fail, noise can be disturbing to folks living inside.
How to access turbine for service--People walking on roofs/accessing turbine once a year for service is usually not a good idea.

Are any of the above reasons that say you can't mount on a dwelling--Just good reasons not too...

-Bill

Gloves · October 2010

Re: 450W Turbine mounted on roof

Keyturbocars, You are right. This is a cheap turbine and it is for hobby. I know
Volts doesn’t = power but i’m seeing volt ratings up to 35V at peak gusts. It
easily reaches 15V dunning moderate winds.

10 blades… I did read that having an even number of blades can result in more
vibrations and more blades generally costs more.

Jesica! The tree isn’t stupid, the tenant isn’t even stupid, it’s the landlord and
previous tenants in this house. They let the poor thing grow out of control. In
any case, I don’t believe the tree blocks the Western or Eastern winds. (from the
west in Summer, from the East in winter). The tree isn’t going anywhere. Their
backyard is quite funny, if I get a chance I’ll take a picture. It’s like living next to
the Amazon.

Everyone here agrees that I need to un-mount from the roof and mount on a pole?
Hrm. I’ll look into that, not sure my backyard has enough space for the guywires…

BB. · October 2010

Re: 450W Turbine mounted on roof

It is a small turbine... What it your tolerance for risk?

You have it already mounted and you can throw something on it to monitor the power output (perhaps one of these DC AmpHour/WattHour meters would be interesting).

See what the output kWH/kAH per month numbers are... If you are generating $0.10 worth of electricity (less than 1kWH) per month--then any risk (damage to roof, annoying noise, etc.) is pretty much not worth it.

If you get $10 per month worth of power (50-100 kWH)--Then perhaps you leave it up and see what happens.

-Bill

Gloves · October 2010

Re: 450W Turbine mounted on roof

B.B. That's a great idea. Exactly what I need.
I have an idea that it does very little to charge these massive batteries.

Example:

Idle batt voltage: 12.5V
When wind is blowing batt voltage: 12.65V (peak)
When I apply a 3A plugged in battery charger: 12.75V (all the time)

Tell me if my math is correct...
225Ah capacity will take 75 hours at 3A...

or 2-3 years worth of wind!!!

I ordered the solar panel.
4 hours of good sun a day @ 6A = 24ah a day.
fully charged battery bank in 9 days.

Hows my math? I'm guessing all over the place here.

BB. · October 2010

Re: 450W Turbine mounted on roof

Gloves wrote: »

Tell me if my math is correct...
225Ah capacity will take 75 hours at 3A...

At least--probably a lot more (self discharge, less than 3 amps near end of cycle, etc.)...

A practical recharging rate range for a cycling battery bank is (very roughly) around 5%-13% of the bank AH rating (we use the 20 hour rate)... So:

225 AH * 0.05 = 11.25 amps minimum
225 AH * 0.13 = 29.25 amps maximum

So, if your charging source does not fall within the above range--you will have some issues (too little current, takes too long to charge, does not "stir" electrolyte, self discharge large part of charging current).

Too much current is expensive (big panels, big chargers) and can overheat flooded cell batteries with too high of charge rate. The charger will usually cut back on current--so a larger charging source is not the end of the world--just expensive to justify the extra (and usually unused) capacity.

So, the minimum amount of solar panels I would suggest for a "nice" minimum sized system would be (assuming 5% minimum rate of charge, 0.77 derating, 14.5 volt charging voltage):

225 AH * 14.5 volts * 0.77 * 0.05 = 125.6 watts

or 2-3 years worth of wind!!!

I could not predict how much power your turbine will produce...

In the end, you want to keep the battery above ~75% state of charge--If the battery spends days/weeks/months below ~75% state of charge--It will lead to battery sulfphation (crystallizing/hardening of the lead sulfate on the plates) and reduction in battery capacity.

I ordered the solar panel.
4 hours of good sun a day @ 6A = 24ah a day.
fully charged battery bank in 9 days.

Usually, we like to derate everything to account for the losses of the entire system... If you have an AC inverter and flooded cell batteries, the end to end efficiency (panel to charger to battery to inverter) runs around 0.52 of rated capacity...

If you drained your battery bank to 20% state of charge (going to zero state of charge can permanently damage the battery):

225 AH * 12 volts * 0.8 discharge = 2,160 Watt*Hours of stored power
135 watt panel * 0.52 derating * 4 hours per day sun = 280.8 WH per day
2,160 WH storage / 280.8 WH per day = 7.7 days

Normally, you would try to limit the maximum discharge to your battery bank to 50% capacity--So that gives you ~3.8 days to recharge your bank (with no loads).

Hows my math? I'm guessing all over the place here.

Your math is OK--But you have to take losses into account... For a PV system, you do lose about 50% of the solar panel rated power through the entire chain to support your loads.

In the end, most people underestimate their loads and overestimate the output energy of their solar PV system.

-Bill

dwh · October 2010

Re: 450W Turbine mounted on roof

Older used batteries can have as much as 1% self-discharge per day. So depending on your battery bank size and age, that single solar panel might only be enough to keep up with the self-discharge rate of the battery bank.

Just have to see how it does I guess.

Gloves · October 2010

Re: 450W Turbine mounted on roof

BB that math is awesome. thanks.
So i did alright with the 120 W solar pannel?

DWH, I have 2 T-105 batteries in series = 12V
http://www.trojanbattery.com/Products/T-1056V.aspx

Tell me about this auto-discharge rate and will my solar cell be able to charge them?

BB. · October 2010

Re: 450W Turbine mounted on roof

120 watt panel is fine for a start.. If you end up drawing lots of power from the battery bank--you will probably want to add a second 120 watt panel (more power;)).

-Bill

keyturbocars · October 2010

Re: 450W Turbine mounted on roof

Gloves, you will probably be much happier with the charging ability of that solar panel. As BB mentioned, you can always buy another solar panel if you want more charging AMPS. Your neighbor's backyard does look like a jungle! At least you get all that great oxygen to breathe.

BB. · October 2010

Re: 450W Turbine mounted on roof

You can read through a couple Battery FAQ's for the basic information (know your battery;)).

Deep Cycle Battery FAQ
www.batteryfaq.org

Flooded Cell batteries (especially fork lift types which already have higher self discharge) may start out at 1% per week in loss capacity (AGM's are 1-2% per month)... And end up with 1-2% per day...

That does not sound like much--but in off-grid solar--power wasted is money lost.

225 AH battery bank * 12 volts * 1% = 27 WH per day self discharge
135 watt panel * 0.52 derating * 4 hours per day sun = 280.8 WH per day

So at 1% self discharge, the 135 watt panel will be providing ~10% of its output to keep up with self discharge...

An older battery with 2% self discharge on a winter day with 2 hours of sun per day:

225 AH battery bank * 12 volts * 2% = 54 WH per day self discharge
135 watt panel * 0.52 derating * 2 hours per day sun = 140 WH per day

You are now wasting over 1/3 of the panel's output trying to keep the battery charged.

-Bill

russ · October 2010

Re: 450W Turbine mounted on roof

@ Jessica - 5 inches of concrete on the roof? If on top of a wood structure it may or may not dampen out much vibration - depends on the frequency generated.

I actually have that - 4 floors of all concrete frame structure - but very few houses in the US are built that way. There are also two towers designed for solar panels but I don't think I would put a turbine up there. Still too much interference from the structure.

A URL for site selection that seems good http://www.solacity.com/SiteSelection.htm

Regards,
Russ

Gloves · October 2010

Re: 450W Turbine mounted on roof

BB. too many numbers! I know you want me to get a 2nd solar panel but i'm going to take it a baby step at a time.

keyturbocars, as much oxygen as it produces, it produces twice as many bugs!

Can't wait for the kit to get here.

BB. · October 2010

Re: 450W Turbine mounted on roof

No--I don't make one cent if you purchase another panel.

You are on the lower edge of the range we recommend for charging current to battery capacity ratio--but it will still work pretty well for you.

I was just trying to show why we pick these rules of thumb (5% minimum charging current, etc.)... It makes for a "balanced system".

-Bill

450W Turbine mounted on roof

Comments

Categories