On Apr 26, 7:06*am, wrote:
On Mon, 25 Apr 2011 22:45:54 -0700 (PDT), harry
wrote:





On Apr 26, 2:48*am, wrote:
On Mon, 25 Apr 2011 16:49:17 -0700, mike wrote:
I have a proposal on my fridge for 2.3KW of solar for $17,250.
They are only really willing to say I will average about 13.8 KWH a
day over a year (5037 KWH a year). I pay 13 cents a KWH so that is
$654.81 a year. That pays back in 26.34 years if it doesn't break or
get blown away by a hurricane.
The federal government will kick back 30% and that drops it to a bit
over 18 years.
The state promised to kick back another 53% but that program ran out
of money and the people who planned on that money are swinging in the
wind right now. With all of the tax payer kickbacks it really made
sense but like all things too good to be true, the deal evaporated.
I was also not really that excited about the grid tie because if the
power is out, all of that generating power on your roof is out too.
The grid tie inverters only work when the grid is present.
That'a a real kick in the ass too, ain't it? * I was quite surprised
about
that when I first learned it. *I bet most people don't even realize it
works that way. *I wonder what the core issue is here and why
they haven't figured out a way around it?- Hide quoted text -

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The core isssue is safety. *If someone isolates and electrical circuit
they need to know it's dead, not being back fed from a PV system..

The core issue is energy storage.
Grid tie uses the utility as "storage".
If you wanna operate off-grid, you need some form of local energy
storage.
Unbuffered solar is very unreliable, even when the sun is shining.

I have a golf cart. That is about 1200-1500 A/H of storage, right in
my garage.- Hide quoted text -

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You must live somewhere with more sunshine than me.
I have a 4Kwp array and the predicted power generated is only 3200Kwh.
Aspect is near perfect too.
On a sunny day, it's doing around 20Kwh daily.

I would check these calculations out, they seem very dodgy to me. If
my installation was in Ca, I would only get 4500Kwh.

South Florida.
They were telling me I should count on about 5 hours worth of the
rated capacity, averaged over a full day.- Hide quoted text -

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Well, I have had my array for only a week. One a bright sunny,haze
free day it does full capacity for only a couple of hours. I get half
capacity for a further four hours or so & a third for a further four
hours. It runs for long periods in the evening at around 150w,
probably not relevant to you in Florida.
In heavy overcast I get 200W, maybe 500w around midday. As our days
lenghten I will get more power obviously.
I have noted that even a slight haze knocks 500w-1000w off the
generated power which might be an issue in your climate.
One thing definitely against you in Florida is they are less efficient
when they are hot.
In Winter we have long gloomy periods in the UK when I shall be lucky
to get 3 or 4 Kwh/day I suppose.
Watch out for shading, ie shadows being cast over your site, major
issue as if one panels is shaded it affects them all on the same
string.
If the inverter overloads or detects high/low grid voltage it will
shut down. This may be an issue that effects you.