beppington
Elite Member
A house paying an average electric bill of $200/ month since Jan. 1977 would've paid a total of ~$79,000 over that ~33-year period.
Curious how you've fared against that, if you've kept track or even a guesstimate?
Went solar
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A house paying an average electric bill of $200/ month since Jan. 1977 would've paid a total of ~$79,000 over that ~33-year period.
Curious how you've fared against that, if you've kept track or even a guesstimate?
clemsonfor
Super Member
i use a 13W incandesant on the range hood and has been the same light for 2-3 years stays on all night and sometimes all the next day
clemsonfor
Super Member
Was not alive in 1977 but i would guess a power bill of $200 today would have been more like $100 back then.
beppington
Elite Member
Agreed: That's why I said "average".
eepete
Platinum Member
I just looked at my power generation for today. Enclosed is the plot for it.
Yesterday it was 68 degrees, clear blue sky, windy and occasional cloud.
Today it is 80 degrees, clear blue sky and absolutely no clouds.
Two things to see here: The peak energy was higher yesterday when it was cooler than today. The 2nd thing to see is that if you look at yesterday, you can see an average power "top of the peak" that looks a lot like the smooth peak of today, but every so slightly higher. You especially see that in the 1st half of yesterdays power output.
What happened yesterday is when the cloud would come over, the power dropped. The panels had a chance to cool off and the winds helped. When the cloud went away and the sun hit the array again, there was a peak in the power that then backed off as the panel heated up. I can see this if I look at the power output display on the inverter- when you come out of the clouds, there is a peak (say 6900 watts) for about 10-15 seconds, then it drops off by about 50-200 watts as the panels heat up. What you see on the graph are the little spikes in the power output.
Now I also suspect that with the higher temperatures came higher humidity, and that drops the amount of sunlight hitting the panels. I also suspect that since there is just a light breeze today, the panels are not cooling off as much. Then add in the drop due to the higher ambient temperature, and you see why there is less power today than yesterday. The inverter would also be slightly less efficient since it's also 10 degrees hotter.
Anyway, the plot is a good example of some of the effects of the temperature of the panels, and also points out that there are many factors influencing the output (ambient air, panel temperature, humidity, clouds, wind, inverter efficiency vs. temperature). I've got to work on my plotting software- I need a way to enlarge sections of the plot to see these effects in better detail.
Pete
Yesterday it was 68 degrees, clear blue sky, windy and occasional cloud.
Today it is 80 degrees, clear blue sky and absolutely no clouds.
Two things to see here: The peak energy was higher yesterday when it was cooler than today. The 2nd thing to see is that if you look at yesterday, you can see an average power "top of the peak" that looks a lot like the smooth peak of today, but every so slightly higher. You especially see that in the 1st half of yesterdays power output.
What happened yesterday is when the cloud would come over, the power dropped. The panels had a chance to cool off and the winds helped. When the cloud went away and the sun hit the array again, there was a peak in the power that then backed off as the panel heated up. I can see this if I look at the power output display on the inverter- when you come out of the clouds, there is a peak (say 6900 watts) for about 10-15 seconds, then it drops off by about 50-200 watts as the panels heat up. What you see on the graph are the little spikes in the power output.
Now I also suspect that with the higher temperatures came higher humidity, and that drops the amount of sunlight hitting the panels. I also suspect that since there is just a light breeze today, the panels are not cooling off as much. Then add in the drop due to the higher ambient temperature, and you see why there is less power today than yesterday. The inverter would also be slightly less efficient since it's also 10 degrees hotter.
Anyway, the plot is a good example of some of the effects of the temperature of the panels, and also points out that there are many factors influencing the output (ambient air, panel temperature, humidity, clouds, wind, inverter efficiency vs. temperature). I've got to work on my plotting software- I need a way to enlarge sections of the plot to see these effects in better detail.
Pete
That was a fair answer. At least we would all be on the same playing field, and that is all I ever ask.
k0ua
Epic Contributor
Hey eepete, how clean RF wise are your inverters,? I know they can be, but the one inverter I have (tripp-lite) is so dirty I cannot use it for any radio work. and are they pure sine-wave,? Did you have to put on any suppression?
Thanks
James K0UA
Thanks
James K0UA
eepete
Platinum Member
The inverter is a Fronius IG Plus 10,0-1 (a 10 KW inverter). In the manual, they define what FCC class A (commercial) and class B (residential) are. But then, under FCC compliance they just say "This device complies with Part 15 of the FCC Rules. Everything I make I have to have tested, typically to class B, and state that so I don't know what's up there. This device is sold globally, so I suspect it's pretty clean.
I know it has a power factor of 1. At night, when it's off, there is 1 amp of out of phase current which make me think there is a lot of filtering on this thing. I need to change my power monitoring to factor in this out of phase current so that low power readings are more accurate. I know it is a multi-step inverter (vs. the tripp lite stuff which is a square wave- I have one of those). The inverter is a high frequency PWM type, so it probably is very close to a sine wave. The harmonic distortion is < 3%. There are three identical inverters running in parallel in the device for efficiency reasons (at low power levels, only one inverter runs, etc).
With the cooler weather, I might take the spectrum analyzer out a take a peak some day. I hear/see no interference on the AM bands, 6M, FM band, 140/150 VHF, 220, 440, all TV channels and the 800 MHz trunking radio stuff. Not as good as sweeping it, but not bad. And I've got 8 channels of UHF modulated NTSC for security cameras so I'd see if there was any change in the noise floor there. I've not taken my HF receiver and tuned around at random looking for birdies.
Guess that's every answer but "I know for sure". If I sweep it someday, I'll update and post it.
Pete
I know it has a power factor of 1. At night, when it's off, there is 1 amp of out of phase current which make me think there is a lot of filtering on this thing. I need to change my power monitoring to factor in this out of phase current so that low power readings are more accurate. I know it is a multi-step inverter (vs. the tripp lite stuff which is a square wave- I have one of those). The inverter is a high frequency PWM type, so it probably is very close to a sine wave. The harmonic distortion is < 3%. There are three identical inverters running in parallel in the device for efficiency reasons (at low power levels, only one inverter runs, etc).
With the cooler weather, I might take the spectrum analyzer out a take a peak some day. I hear/see no interference on the AM bands, 6M, FM band, 140/150 VHF, 220, 440, all TV channels and the 800 MHz trunking radio stuff. Not as good as sweeping it, but not bad. And I've got 8 channels of UHF modulated NTSC for security cameras so I'd see if there was any change in the noise floor there. I've not taken my HF receiver and tuned around at random looking for birdies.
Guess that's every answer but "I know for sure". If I sweep it someday, I'll update and post it.
Pete
schmism
Super Member
not to hyjack the thread but yes we are seeing that in our area to. our budget included fencing, small 20x20 ish building aka barn. There are a few people in my area that would give away alpacas and lama's also if they went to a good home. The budget was not just for paying for the animals :thumbsup:
on the falling price of pannels.
When we moved to the property in 2007 it was at the top of my to do list. like within a year. I had priced everything, had paperwork printed out... ready to go. just other projects kept comming up with the new property that we wanted to use that cash for.
at that time (3 years ago) a "good" price for a panel was $5 per watt.
per my research today "good" panels can be had for $3 a watt.
not to mention better inverters that do more for less money. Battery tech continues to evolve and if we see some mass manufacture of Li-ion packs for EV cars comming next year (like the packs Tesla motors is selling to Daimler in Germany) then we should see a huge jump in battery performance per $ for off grid, backup systems.
Our plan was to start at about a $5K system. with an inverter that would take up to 2K watt's of DC (wind/PV) grid tie-able inverter. start at about 600w of pannels and add a 200w pannel (at the time about $1K) a year till we hit that ~2Kw size. Over that 5 or so years we would focus on not only how pannel development evolved but also what are TRUE output would be for our area/installation and how that compared to our usage and how we might trim usage at the same time.
We felt for "city folk" moveing to the property the transition listed above would give us time to adapt to the system, get to know it, learn how it works, determine what would be best moveing forward instead of dropping $40K or something "crazy" into a huge system all upfront. (then having some shock about actual output and or actual usage)
Our goal was to never sell power back to the grid, but at the same time not be entirely off grid. But to generate all or most of the power we needed 90% of the time.
k0ua
Epic Contributor
Thanks eepete, I was wondering mostly about HF, I have been working on my ethernet network for a long time, and while much quieter than it was, it is far from clean, with quite a few birdies still on the upper hf bands and even some on 6 and 2. With a lot of ferrites it has went from awful to tolerable.
thanks
James K0UA
thanks
James K0UA