[aprssig] APRS Solar Power (I was wrong)

Brian B. Riley brianbr at mac.com
Thu Oct 1 19:48:30 EDT 2009

On Oct 1, 2009, at 2:57 PM, Robert Bruninga wrote:

> If you have heard me speak recently and I compared 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
> environment:
> 1) Solar panels (PV) are 1% of what they cost in 1970
> 2) PV dropped 40% 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

You left out one thing, though very time sensitive. Some months before  
the economic crash the PV industry was backed up badly with 1-5 months  
waits to get just about any kind of PV panel. The manufacturers  
response was to ramp up production and by the time they did economic  
chaos had fallen. Right now many of  the top manufacturers have rock  
bottom prices on PV. I bought a pair of SolarWorld 175 Watt panels  
last Fall for  $890 each and the motor freight for the two came to  
$221. This past June I bought two more for $715 each and motor freight  
for  that came only to $150! Then in mid-August I found I could have  
them for $625 each! These prices are all from the same dealer.

> 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 are NOT worth it (in most places where you have access to
> the grid).

  This is a big caveat .... In 1988 when I bought my land, Central  
Vermont Power wanted $8500 to extend power up 0.4 miles. In 1993 they  
wanted $10,000 to go 0.24 miles. Last year just for kicks I asked and  
the figure was $21,000.

With the new panels I added and the new batteries I am putting in next  
month, I will just have hit $21,000 in expenses for 21 years, during  
which time I have had no electric bill ... which puts me ahead by  

>  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 $150 1 kW
> inverter 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.
> 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.

Huh, Unless you are using some hinky spartan system, most any grid tie  
system can generate local power in the absence of grid power, just it  
won't get out to the grid (linemen are funny about being blown off  
poles!), of course you are S.O.O.L. after sunset.

>  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
> is.
> 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
> Bob, WB4APR

  PV Works, even in VT
cheers ... 73 de brian  riley,  n1bq , underhill center, vermont
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