Off Grid Living / Camping > Off Grid Living / Alternative Housing
Power Logs
ChrisOlson:
We installed our new 24 volt system last year on April 4. I just tallied the power logs for the last year and we generated 10,499 kWh from 4-4-2011 to 4-1-2012. That averages out to 29.12 kWh/day.
Of those kWh total, 6,564 came from wind power, or an average of 18.21 kWh/day. Of the total, 3,935 kWh came from solar, or 10.91 kWh/day.
The wind generates a lot more kWh in the winter. The solar generates a lot more in the summer. In the last three weeks the solar has been burying the wind turbines for total power output**
Our generator hours from April to April were 356.9, on both of our standby generators combined. That's an improvement over the January to January number, which was 454.7 hours. We have a grand total of 49.4 hours on both generator combined since Jan 1. My goal for 2012 was to cut the gen hours to less than 250 for the year. I think we are well on track to do that. We will never eliminate the gen hours altogether because we depend on them to run heavy loads like the range, sometimes water heaters, and the electric clothes dryer.
We have made two major improvements since Jan 1 that has made a difference in gen hours - I added 500 watts more solar power a couple or three weeks back, plus a Classic 150 controller. And I upgraded two turbines to MPPT machines with Classic 150 controllers. Those improvements have all but eliminated the gen time for "poor power days", as the generators have not started because we're low on power since Feb 27. They have only run for exercise or when the inverter calls for gen power for Peak Load Management.
I look back at the year before and it's appalling. We generated a meager 1224 kWh from Jan 1 2011 to April 4 2011 with our old 12 volt system we had. That's only 13 kWh/day - less than half of what we make now for the whole last year.
I remember those days. I remember in January 2011 I was outside at 3:00 AM at 32 below zero, trying to get a 12 volt Tecumseh gas charger started because we were out of power and the inverter was screaming it's shutdown song. I thought we were doing pretty good. But life wasn't near as luxurious as this last year, as far as how we've gotten used to having real power in the house ;D
**this winter has been unusual. Normally March means we're in the dead of winter and starting to see the light at the end of the tunnel. Spring shows signs of arriving. This year in March, we got green grass, buds on the trees, excessively calm wind, and bright sunny days @ 70 degrees.
The wind power is working overtime tonight, though, with a nice 15 mph breeze out of the ESE. We got a steady 1.7 kW coming in from wind tonight, and that adds up quick. That wind holds out for one day and we get 40 kWh from wind in a 24 hour period. Except the forecast I seen last shows it's supposed to pick up to 25-30 tomorrow during the day. When that happens the Classic controller doesn't let the solar panels work because the turbines got the bank right up against the stops before the solar can even do anything. And I'll probably end up having to shut a couple turbines down because we can only heat so much water when they all start pushing 2 kW.
Interesting, Woof pointed out this really cool map in a different thread:
http://hint.fm/wind/
I have determined that that map is compiled from surface observations at airports. That map shows a 9 mph wind speed for our location, which is what the local airport is reporting. My anemometer @ 74 feet is showing 14.8 mph ave.
--
Chris
birdhouse:
nice work! that child out of college seemed to open a few options for your system to grow, and you can tell from the cold hard numbers!
--- Quote ---This year in March, we got green grass, buds on the trees, excessively calm wind, and bright sunny days @ 70 degrees.
--- End quote ---
that's the beauty of wind AND solar. especially for off grid. it seems pretty darn rare that one of the two isn't producing hard amps.
my system is MUCH smaller, but i can relate to having something (wind/sun) that always seems to be pushing amps!
next step for me is an auto start genset. then i'll be mimicking your system to the T, but still on a MUCH smaller scale.
adam
rossw:
--- Quote from: birdhouse on April 02, 2012, 12:06:15 am ---that's the beauty of wind AND solar. especially for off grid. it seems pretty darn rare that one of the two isn't producing hard amps.
--- End quote ---
Unfortunately where I am here inland in Australia during winter we FREQUENTLY get days (often several in a row) with thick fog that doesn't lift at all, and no wind whatsoever. Some of these days I see 40 watts out of my 3600 watts worth of PV, and absolutely nothing all day from the turbine.
Those days I'm very glad for the propane genset.
ksouers:
Very interesting summation for the year, Chris. Thanks for sharing it with us.
It's also very heartening to read about such a productive system.
Our local power company started providing historical usage online. I downloaded our usage over the past two years and it's amazing how much electricity we use :o
I have a saltwater aquarium that eats a lot of watts but the big sinker is a couple commercial grade servers going 24/7 (partly for my job). I really want to get those off grid ASAP but it's slow going right now.
Could you provide a bit more information about your system? Solar configuration, battery bank and such.
It would really help us guys who are just starting to put our systems together.
Thanks,
Kevin
ChrisOlson:
--- Quote from: ksouers on April 02, 2012, 06:25:22 am ---Could you provide a bit more information about your system? Solar configuration, battery bank and such.
It would really help us guys who are just starting to put our systems together.
--- End quote ---
Kevin, I got a conglomeration of solar panels. I got 10 Sharp 123's. I got 4 Schott Solar 240's. And I got two Helios 250's. That all adds up to 2690 watts installed capacity. I got them wired for series/parallel output and they don't all match. The Sharp panels are 17 volt, the Schott are 28 volt and the Helios are 29 volt. I feed them all except for two of the Sharps into the Classic wired for 56-68 volts and let the Classic figure it out :)
I got the Sharps wired in series strings of four. I got the other big panels all in series strings of two.
I could get more power from the solar if I had separate controllers on each set of panels. But it seems to work OK the way I got it. Each "group" of panels at their various Vmpp's seems to hit their peak at different times and the output is pretty constant all day. I have seen it exceed the total installed capacity by up to 5% at times. I would not recommend this setup as the "ideal", but it was done because of adding panels a bit at a time, and every time I got different panels from whoever had the best deal. The Classic takes it in stride and figures out what voltage to operate them at to get the most power. It'll run the whole works at anywhere from ~34 up to 70 volts at times - whatever it takes to get the job done.
That's a hell of a controller. My system is 24 volts, BTW.
My bank is 2,400 ah. 24 Rolls-Surrette T12-250's. About 30 kWh usable storage. If I had it to do over again I think I would get something different than Surrettes. They are low specific gravity batteries and they require higher charge voltages. I think they waste more power in charging than others because of that, because they tend to run a bit warmer during absorb. It takes 20-25 amps, with no load on my system, just to float the bank.
--
Chris
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