[amsat-bb] Solar Power (I was wrong)

Robert Bruninga bruninga at usna.edu
Thu Oct 1 17:37:45 PDT 2009

Since Satellite design is heavy into Solar power, and I talk
about that a lot, you may have heard me compare my Solar car to
Solar panels on the roof of your house as not economical, I WAS
WRONG.  I was overlooking many recent changes in the

1) Solar panels (PV) are 1% of what they cost in 1970
2) PV dropped 40% this year due to 2007 Energy Boom and 2009
economic bust
4) $5,000 to $20,000 tax and cash back incentives for YOU
5) Grid-tie systems operate at 95% efficiency compared to 70% of
battery systems
6) Local electric rates DOUBLED in the last 2 years
7) Laws require utilities to pay you the same peak rates they
charge you.
8) Solar Energy credits can gain an additional $275 per 1Kw
system per year
9) Payback is at least 10% per year or better
10) The same money in the bank gets 1% interest

So I was wrong in not keeping current with all the changing
environment, and now I am full speed to get my system approved
and built and correct any miss-guidance I may have helped

Sorry. I am claiming this particular email is on-topic because
of public statements to the contrary I have made at satellite
forums.  But this hot topic should probably spin off elsewhere.
We need a HAM Solar Power group somewhere...?

Summary:  Do NOT make the mistake (as most of us do) of thinking
in terms of stand-alone Battery back-up solar power systems .
They cost more and you don't need it in most places where you
have access to the grid.  They cost $5 to $10,000 more, are only
70% efficient (compared to 95% for grid-tie) and are a never
ending maintenance headache.  Instead, most any enterprising ham
should be able to provide his own backup power using a cheap 1
kW inverter for about $150 from any auto store or radio shack
running off his car's 12V system for any power outages.

That, a few deep cycle batteries, (and using CFL lightbulbs in
your house) will give you enough emergency power to operate your
full Ham station, all the lights in the house you want plus your
refrigerator for as long as you can buy gas.  But the other
99.99% of the time, sell your solar power to the power company
(at peak rates during the day) and buy it back cheap at night
(you win and you don't even have to worrry about batteries)...

And even if your grid-tie solar array produces nothing (in the
way of AC power) when the grid goes out, you still have many
Killowatts of DC power on your roof, that you can surely find
lots of things to do with until the grid comes back.  For
example, have the electrician wire a 250 volt string of the 200
Watt solar panels in the array to a DPDT switch so they can be
disconnected from the Grid Tie system and the 250 VDC can be
available to you.  THen you can plug in as many modern DC/DC
pwer supplies into that 250 VDC to give you LOTS of amps at 12
volts, or ... almost any modern gizmo has a universal power
supply input that will run on anything from 110V to 330V DC as

Anyway, for similar hints www.aprs.org/FD-Prius-Power.html

Sorry for the off-topic.  But  I was wrong. PV works! (even in
Maryland).  If you live in the SW, you are lucky, and it works
TWICE as much or at HALF the price!

A Born-again Home PV junkie

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