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Author Topic: Solar for dummies  (Read 7067 times)
cody
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« Reply #60 on: January 24, 2010, 01:55:51 PM »

Sun force has a panel rated at 100 watts that are the CIGS technology, northern tool has them for sale at 599,    http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200379208_200379208     I'm looking at these for starters, one of these next year would be nice too   http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200405533_200405533
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Sean
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« Reply #61 on: January 24, 2010, 02:04:46 PM »

Sean told me the hundreds of thousands of dollars figure,


No, I said "dozens if not hundreds," and I was talking about an average house.  The average house in the US uses 30 kWh per day (on average) of electricity.

Quote
I just can't even see how it would cost the 10K your talking about,


If you want 100% solar, it's easily that.  Let's do the math:

Quote
heres the numbers and you tell me what I need, I have 8-12 watt CFL light bulbs, a 32 inch LCD tv, the toaster and coffee pot are the heavy hitters but only run on occasion, a refrigerator that uses 6 amps at start up, the laptop, and a well pump that uses 9 amps when it's running.  I don't know the amps needed for the tv and the toaster and coffee pot would be the major hitters but I don't know the wattages of them, occasionally a microwave, it's a 450 watt unit. thats the total power thats out there at this time, now I can't see where that adds up to any major usage.


OK.  Without more specifics (you really need to measure those unkown items, especially how long the pump runs each day, the fridge, etc.), we can take a guess.  I have an extremely energy-efficient bus, and I use most of those same appliances (LCD TV, coffee pot, microwave, a few lights, etc.) with the exception of the well pump.  Also, I have a super-efficient fridge, which uses less than one tenth what yours does.  With all that, I use about 4.3 kWh per day, when I don't need A/C.

Lets add another 2.5 kWh for your fridge, and 4.2 kWh for your well pump (which would be about two hours run time each day).

That brings your daily requirement to 11 kWh, give or take.  That's still far less than a normal household.

Quote
... I had used a total of 78 KWH for that month, does that help in figureing it out?


It would, except it doesn't square with what you just told us above.  That would be 2.6 kWh per day, just barely enough to run a household fridge.  Was this a month where nobody was home?  Or perhaps is there a "base quantity" of kWh included in the flat rate you must pay, and the 78 is a number over and above that?

In any case, I'll do the math both ways:

Lower limit, 2.6 kWh per day:

With panels ideally angled (due south at 46 elevation, with no shade-producing elements nearby), at your latitude, tables generally suggest a four-hour "sun-day", which means each panel produces its rated wattage for that amount of time each day.

To generate 2.6 kWh in that four hours, you would need 650 watts of panels.  However, you will be storing this in batteries, and the storage/retrieval process extracts about a ten percent penalty; you will need an inverter to change DC to AC which extracts another ten percent, so you will  really need about 820 watts of panels.

At the best prices today, 820 watts will cost you about $2,500.  That's not including cabling, mounting, etc. etc..

Now you will need to store that 2,600 watt-hours of energy.  At 12 volts (the most common nominal battery voltage), that's 217 amp-hours.  Because batteries should not be drawn down past about 50%, you'd need at least two 220 aH batteries, but you'd never be able to change them to 100% with this system.  Batteries follow the 80/20 rule, so we really want the 217 aH to be drawn between the 50% and 80% levels on the batteries; that means you'll need about 720 aH of batteries.

If you are willing to maintain wet batteries, a dollar per aH is a really good price.  So add around $720 for the batteries.  Now you are up to 3,220.

You will need a good sine wave inverter to run your system, at this rate about 3,500 watts.  If it is 100% solar, you do not need a charger.  Still, you will need one capable of starting the pump and fridge, and it will have to produce both 120 and 240.  You will need to budget at least $2,000 for such an inverter.  Now you are at $5,220.

Add to this the cost of battery racks, cables, mounting hardware, junction boxes, etc. and you will easily be over $6,000.  That's just for 2.6 kWh per day.

If my original estimate of about 11 kWh per day is closer, you'd need:

2,750 watts of panels, $8,250
3,055 amp-hours of batteries, $3,055
A bigger inverter, $3,000
Miscellaneous cables and hardware, $1,000
Total: over $15k

And, again, the average house uses three times this amount of energy, and some even more, which is why I say it runs to dozens or in some cases hundreds of thousands of dollars.

-Sean
http://OurOdyssey.BlogSpot.com
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« Reply #62 on: January 24, 2010, 02:07:52 PM »

your magnum inverter is a pretty good start.
if you have the batteries also you are set

yes you can use the feeder.just look into the main breaker bob and get the two busses connected to run with your gen.
i would go with the larger gen unit.
the inverter adjust charging rate on the peak voltage available.
the small honda is allready on its limit for the charger ,not getting you full rate.
you will try to keep your batts full charged most off the time (we call it floating)
that will extend their lifetime.
on the other hand you want them to charge also not to slow,as these inverters will charge in  three steps.
if it takes to long to get from charge to float you will have excess gassing and shorten the life again.

that one of the secrets of a balanced system.everybody that has battery problems has mostly to big off a bank or to small.yes you can have to much also.you need to get them fuly charged in reasonable time.


neverending story
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Sean
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« Reply #63 on: January 24, 2010, 02:12:22 PM »

... the well pump is 110 volt and the inverter is a magnum 2800 watt pure sine wave inverter/charger, I kinda think it is a REAL inverter unless I'm mistaken which I could be.


Sorry, my last message assumed a 240-volt well pump -- not sure where I got that.

Your 2800 pure sine will probably run everything, except you might have a problem if the well pump and fridge both tried to start at the same time.  These are good units.

So you can take that part out of the calcs.

In order to size the batteries and panels, though, we really need to know which is closer, 2600 watt-hours or 9,000.  (I overestimated the pump usage based on the incorrect voltage.)

-Sean
http://OurOdyssey.BlogSpot.com
« Last Edit: January 24, 2010, 02:16:36 PM by Sean » Logged

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cody
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« Reply #64 on: January 24, 2010, 02:26:37 PM »

The 8 batteries are rated at 105AH and are AGM so that is 840ah of power with 420ah usable, the well doesn't kick in very often cause of the 100 gallon pressure tank and the refigerator doen't run very often and is new and energy star rated, I was wrong on the amperage for it, I just dug out the paperwork on it and it says 3.8 amp, I went thru the power bills for 12 months and the highest power bill was 104 KWH and the lowest was 58 KWH, I intend to use the 6500 watt onan but not until I get a quiet box built for it, then I'll put the honda back into the bus.
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« Reply #65 on: January 24, 2010, 02:45:46 PM »

The 8 batteries are rated at 105AH and are AGM so that is 840ah of power with 420ah usable,


Those should work.  I would invest the $150 or so into a really good solar charge controller, such as the Blue Sky, to maximize the output while at the same time protecting these batteries.

Quote
the well doesn't kick in very often cause of the 100 gallon pressure tank and the refigerator doen't run very often and is new and energy star rated, I was wrong on the amperage for it, I just dug out the paperwork on it and it says 3.8 amp, I went thru the power bills for 12 months and the highest power bill was 104 KWH and the lowest was 58 KWH, I intend to use the 6500 watt onan but not until I get a quiet box built for it, then I'll put the honda back into the bus.


OK, so sounds like 90 kWh would be a good average, or 3 kWh per day.  That, by the way, is really, really low for a house.  Congratulations.

Since you already have the batteries and the inverter, you'll just need to add the panels.  Based on the 3 kWh, I would estimate you would need roughly 1,000 "watts" of panels, well aimed.

For winter use, you would want to tilt them at latitude+15, or about 60 from horizontal in your location (pretty tall!).  For year-round, go with latitude or about 45.

If your inverter is 12v, you'll want to go with 12v (nominal) panels in parallel.

If you really shop around, you might pick these up for $3,000 or so.

Don't skimp on the wire.  Use at least #6 to wire from the panels to the charge controller, and #4 charge controller to the batteries.  Better to use #4 for the whole thing.  I'd use 0000 for the inverter battery connections, with a 450-amp class-T fuse.

Here are some good references:
http://www.solar4power.com/solar-power-basics.html
http://www.backwoodshome.com/articles2/yago90.html
http://www.qsl.net/ve3lgs/solarpnl.htm
http://www.solar4power.com/solar-power-sizing.html


-Sean
http://OurOdyssey.BlogSpot.com
« Last Edit: January 24, 2010, 03:47:32 PM by Sean » Logged

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« Reply #66 on: January 24, 2010, 03:44:18 PM »

i guess everybody here is right on some part!!

i just try to tell everybody,dont get scared go for it.

i was counting the same as sean has done it here.and from the numbers he is right.
but i found that there are many factors that cant be counted.
i designed my system with no background on solar.went with the same numbers as i was living before etc...
when i had my first 1000w panels up i was allready starting to build the second rack for the next array.
as i had planned my system needs to be way bigger.
my living and energy conserving changed so much,that by the time i was ready to set up the second rack i didnt need it for living!!

its the small things,like unplug the tv,turn off lights,remove the defrost timer in the fridge and defrost manual etc,that makes together real savings!!!
again,if you dont learn from it and dont change you will have to pay for it!!!

so go for it,try it!!! you have the basics to try and learn and go with it.
just take you time to watch,learn and understand whats going on.

as i say,its like my bus
lots of ideas in the beginning,and then you find out whats important when on the road and whats
just wild dreams and made no sense!!


that me
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Lonnie time to go
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« Reply #67 on: January 24, 2010, 04:14:42 PM »

when i started ,i found that the cheapest way was to start on the generator site.

if you do it longer you will find out that a diesel is must!!!

i went later with a Listeroid engine coupled to st gen head.
running all night on two gallons and heating the house by using the waste heat from the coolant!!

i went trough severall onan,kubotas,you name it.
got tired of maintenance and cost for filters gasketts.......

whenyou got the gen.you can focus on an inverter and a battery bank.
keeps you from running the gen at night,when almost no power is needed!!



Ok few questions

what size    Listeroid engine
                 generator head

How often do you run

How many watts is produce

any info would be appreciated

Lonnie






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« Reply #68 on: January 24, 2010, 04:25:46 PM »

for the house i run a 6hp single
i have a 5kw head on it.its way overkill for the engine,but the extra mass on the rotor makes it more stable on starting loads!!

run time depends on lots of things
like weather,how much wvo im processing etc.
in winter i run it between 8-14 hrs to also heat the house

i have set it at a light load to work as a charger mostly
set at 1500 watts,trying to keep it loaded all the time

for busy times,lots of welding or work on my lathe i have a
witte 12hp oilfield engine running next to my shop
its also connected to charge house batteries while running ,so its never running
unused if once started

i like old engines,and this gave me also the chance to run them with a reason.
next project would be a fairbanks YH 25 hp single
but thats next summer or?Huh...
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« Reply #69 on: January 24, 2010, 05:52:05 PM »

Cody, I suspect you'll find a way to use solar or wind for electricity and do it on the cheap.

I do admire you for being able to get by with so little electricity use.  I have no idea how I am using so much electricity.  Certainly, leaving my computer on all the time isn't helping things.  I don't own a big screen TV or much in the way of electronics.

My energy usage overall is relatively low for living in Minnesota where it gets cold.  My average electric/gas bill for last year was $133 a month.  It helps that I have a pretty new house that has an air exchanger, extra insulation, nice Andersen windows, and was sealed against air leakage during construction.  I'm still using a lot more electricity than you are.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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