On May 18, 4:00*pm, Andy wrote:
Andy replies

Jim, I am using the 50K number which someone who claims to be
knowledgeable about the issue posted yesterday on this newsgroup
in a thread with a similar name. I don't know, personally, what an
installed system costs.

If you don't even know what one costs, wouldn't it be better
to start there instead of starting another post based on
assumptions you have no knowledge about?



* *I am also using "his" allegation regarding federal subsidies and
state and municipal rebates... If I am incorrect, I'm sure that anyone
who
is pursuing the matter will want to get his own numbers anyway and
not rely on newsgroup advice.....

Gee, you really think so?




* *My purpose is to point out that, regardless of "subsidies" that
are
borne by the taxpayers, *there are many other factors to consider in
this
endeavor, that most people might only find out AFTER they are too
committed to back out......

* * I find it reasonable for the numbers you quote, assuming that
similar rebates apply to the user. They sure don't apply where I live,
tho..

* * And I am curious at to the 5kw system you mention. *If that is 5K
peak
watts from the array, that would only apply in "full sun", which the
tables
say averages 5.5 hours per day in the Dallas area.....
That's about 27 kwh per day, which is probably reasonable for around
here.
But for those areas that have less than 5.5 full sun hours per day,
like maybe
Seattle (as a guess), that capacity wouldn't be enough.....

* * In addition, to achieve the 27.5 kwh/day, the array would have to
be
tracked so that the sun would be "normal" to the array for the full
day.
Since I assume the array would be mounted , fixed, onto a roof, the
output would be significantly less, and would be a cosine function
for
the average value, about 64% or so (from memory), *and then only if
the roof slanted in the
proper direction..... So, you see, there is more to this than the
factory
specs, which will normally assume an optimum mounted system....

Gee, you mean it's not as easy as hooking up an accessory to a
computer?


However, those are technical factors which one also finds out about
only after having the system installed, not realizing the "quoted"
potential,
and then learning the engineering behind the system....

Most people are never going to learn the engineering behind the
system. Good thing they don't have to either, otherwise all
the school teachers, lawyers, etc would never get one
installed.




* *Anyone who can afford 25K ( or 50K, whatever) for a system has the
ability to learn these factors and do the tradeoff for themselves
BEFORE
making the committment , since "it ain't rocket surgery". * My purpose
in the posts I have made is to encourage everyone to do so, and not
be
deterred by anyone who says "it's too complex for you to learn so you
should
just fork over the money"....

I didn't see anyone here making the claim that people should just
fork over money. The only outrageous claim regarding
complexity was that YOU said installing a residential PV array was
as easy as hooking up an accessory to a computer.




. *Actually, anyone with a ham operator
license above novice class has demonstrated more electrical knowledge
than
is presented in a "PV installation class", *so while such a class
might be useful,
*(or not), ANYONE can learn to do it......

Seems like a broad assumpiton, unless you've actually
taken the class. And even if one does learn it, in most places
in the USA they can't install one for someone else unless
they are a licensed electrician. In many places they
could probably install it on their own house.

But, if it's really pitfalls that you're worried that people
could fall into, why not bring up the obvious issue of
warranties. I'd suspect that on a DIY install by the
guy who doesn't even take a class, there is a good
chance the warranties on the system will be kaput.




* *So, as an engineer who has done a lot of this kind of thing, I'll
simply say
that the knowledge required to hook up a PV system is insignificant
compared
to getting an engineering degree, and there's lots and lots of
engineers....
I'd compare it to changing the oil in your truck, or doing a brake
job,
which doesn't require a PhD
in mechanical engineering to accomplish, tho many many things can go
wrong......

I can legally change the oil in my friends truck. I can't legally
install a PV array on his house here in NJ because I'm not
a licensed electrician.