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.
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:
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.
... 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
