Wind - "Not for the faint of heart"

[gww]

Oz
I read that every day you post, I don't really know why.  Every single modification you preformed went right over my head.  All the advice you gave others who you helped in their threads went right over my head but I still read it all.  Every time I see some one with power jack I refer them to your post.  Many they will understand.  I'll be like the guy with no money who went to a millionares bbq and now thinks he's a millionare too.  Thanks for taking the time to share.
gww

[oztules]

Gww, thanks for the kind words..... now...
If we are going to use cheap solar effectively for life style,and not figures, we need to shift the way we think.
With limited solar we need to get the azimith and angels correct, use mppt, and generally wring the max kwh out of the panels we can...... but...

If we have lots of solar,  (and it is dirt cheap now), we do things different..... first throw the books away.
I have so much solar I do NOT want it all performing as well as it can.... I can't use 10kw..... so I want to spread the kw over the day IF it is sunny.

I don't want or use mppt ( except it is in the grid tie ).. so simple pwm odes fine. $20 dollar controller will control 100 amps@ 60v or more... so cheap.

I don't want the panels set for 45-50 degrees as I should for this latitude, I want them to be predominately 15 degrees or so for the main banks... why??? because i don't particularly care where they are when the suns out, they will over power the system anyway, and need tempering from the pwm

It is when the sun is not out that we need to give some thought. Trackers are useless for this. Ambient light will come from near everywhere, and a panel pointing straight up will do best in a lot of cases, but we still need some angle to keep it clean... no other reason.

Local factors then need to be counted in. We need to set the system for what happens in the lousy insolation days.

Here the sun if there is going to be any in the winter seems to be in the first few hours of the day, and then it clouds over for the rest of it.... so a few kw pointing east at 25 degrees will get the best of morning sun, rather than using 45-50 degrees facing north ( southern hemisphere ) If I can get a few kwh early in the morning, I will have gone a long way to replacing the o/night stuff.

If it is a cloudy start, we get all the panels working, as there is no light point in the sky to face anyway.
A kw facing west for late afternoon topping up as long as we can before the sun sets is next. Probably 25 deg or so will do, the rest can point north at 15 degrees.

Moral of story, plan the system for WORST light days, and not give a toss about sunny days.

Today the place was fogged in , but the capture was such that 25 amps was coming in from fairly early on, as the whole sky was white, and radiation was coming from N S E and West.... so planer panels were best..... but at 9.30am. the sun came through , and we shot up to over 90 amps@55v or more, and it has been adding amp hours at a 45 second rate... it does not take much sun to fill the thing and begin pwm control.

10am came, the 2.5kw hot water started up to replenish the o/night temp loss ( about 10- 15C for 120liters) from showers dishes etc etc. It finished the night at 53C.. so it will use a few kwh to get back to 65c, and turn off.

The rest of the day will be spent in absorb..... very boring which is what we want. A sunny morning will see it full at 9am in the summer... the rest is waste unless you want to irrigate with a big motor, or use air conditioning all day, and that would not be seen anyway.


...............oztules

[oztules]

continued... had to take someone to the airport...

I use 60 cell panels, and this gives us the best amps, and also attenuates near to 60v on it's own.... and we don't want much power at that voltage point anyway... hence mppt is not necessary. If you can only source 72 cell panels, then maybe mppt can be of use on poor days, else not worth the bother.

I push the batteries up to at least 58v before I attenuate, and they are held there for  most of the time.... high by most standards, but the batt manufacturer claims that provided it is less than 48 hrs at a time, will be fine... then float.

Being a cyclic system, and charge coming on only for part of the 24hr cycle, float is a useless concept, unless you go on holidays.... big windmills would change that paradigm, and float would be an option.

Every now and then I push it to 60v for 4-5 hours for equalise. I agree with Chris Olsen that you push lead acid hard, or lose it. It needs bubbling every day to keep the liquid reasonably unstratified.

I do SG readings every day still, and can see what he means. If I take morning readings, they still seem almost  fully charged ( even though I have used 80ah overnight), and you can charge fairly hard, and see no increase and in fact sometimes a slight  a decrease for  while as the lighter acid stays at the top. It is not until you get the bubbling going that the level increases to 1.275 and beyond, as otherwise the acid you measure above the plates has not been involved in the changes, and so the lighter fluid stays on top, the heavy fluid at the bottom of the cell, and we get false SG readings.

I will stay with flooded lead for the next decade, and re-evaluate, but I suspect will stick with the flooded cells even then.provided the temp stays low ( mine are outside air cooled), they need overcharging far more than under charging for good health.

So solar......... not wind is the best long term investment for a no compromise off grid installation that does not cost the earth, and is set and forget.
Undersize it, and you will have to start a generator.

Next winter will tell me if I have to use up the 3kw of spare panels stored in the shed. Last winter was lots of testing, this winter will be "did I get it completely right".
With this much solar, summer tells me very little, except I have oodles of power to throw away.


................oztules

I used to think the SG readings were sacrosanct accurate at any time you did a reading... until I observed this pattern.... Chris was right

[gww]

I never get enough hours to get to flote 90% percent of the time.  during winter I get to above a 10% charge rate but have fewer hours and summer my production is hit hard enough that I only get to flote on rare occations.  I do take my battery down pretty low and do absorb a eq rates.  That is the only way to get the sg up without a six hour absorb.  I usually get about 3 and have it set on four.  I keep it close to absorb about an hour cause that is when my hot water starts and it take about an hour to get to full power and reach full absorb voltage.  Low voltage does not raise my sg.
gww

[electrondady1]

..........I see a post from eletrondaddy1,...... still trying to make VAWTs work ...  I guess misery loves company.

i like the way vertical mills look
I'm not Don Quixote.
there is no misery.
all my mills work
I'm having fun .
so.....

[kitestrings]

I'm not Don Quixote.

Now there's more than one layer to this comment; maybe unintended.  Here's where I reveal how poorly my literature background is...but, I recall something about windmills having significance, symbolism.  They were thumbing there nose at the lords, government (controlling force of the day?) in his mind.  Is that close?  Oh great, something else to research...

[SparWeb]

My neighbour has a donkey, can I be Don Quixote for a day?

I've tried to explain my hobby to people many times now.  I often have an exchange that goes something like this:

They- How much power does it produce?
Me -  About a kilowatt when it's very windy.
They- Is it really windy at your place?
Me -  Sometimes.  But these trees here just keep growing taller.
They- But you save money on your power, right?
Me -  No it's not tied to the grid.  They charge you to do that.
They- But you could - wouldn't they pay you then?
Me -  About 50 bucks a year.
They- How much did it cost to build?
Me -  About 3000.  More, since a few upgrades.

People usually don't get that far in the conversation.  Fewer people still bother to ask more, because very few people really enjoy tinkering with things, or can even relate to people to do.  Those that do, typically prefer tinkering with things that go boom, bang, or rumble.  What surprises me most are the number of engineers and technicians who just shrug about it.  I'm fascinated by all sorts of things.

Only twice has someone asked a truly penetrating question or wanted to discuss and see it in detail.  I think most people expect to get the "fairies and flower power" speech, maybe some truly believe in that BS and are disappointed, or confused, that I don't.  How could I have a wind turbine and not believe it will save the world?

Wind turbines really have the "poster child" problem, of being on the cover of green-washing magazines and company brochures, when really they are just a piece of technology.  All the political/social/environmental issues associated with wind turbines are completely in people's heads.  It's that kind of mis-perception that keeps the small-wind industry selling units - people who think it proves something about them.