[RFI] OT: RE: solar problems

K8RI k8ri at rogerhalstead.com
Mon Apr 11 22:32:27 PDT 2011

On 4/11/2011 7:26 PM, Peter Laws wrote:
> On Mon, Apr 11, 2011 at 15:43, K8RI<k8ri at rogerhalstead.com>  wrote:
>> On 4/11/2011 5:46 AM, Cortland Richmond wrote:
>>> If it's a deliberate phase bobble, that's a clever  way for power co's
>>> avoid having to pay people for their solar power.

That would not be in the power companies best interests.  Those things 
cause them all kinds of headaches and "book work"

>> They need to control phase, but there is no need for them to shut the
>> inverter down in the line power is shut off.   The inverter system
>> should have a transfer switch and immediately drop the  connection to
>> the power line.
>> This allows the PV system to work off batteries as a back up.  This type
>> of regulation completely defeats the back up ability of a PV system
>> which is why I'd install one in the first place.  That I can get money
> You're not up-to-date on the latest in the solar industry.

yes I am.  That's why I complain.  They have taken the most complex and 
least user friendly approach to disconnect by shutting the inverter down.

>   Most
> grid-tied systems these days have no batteries (because they reduce
> system efficiency).  The system generates power while the sun is up,

If you are lucky. The payback map doesn't even list MI.

> offsetting part, all, or more, of your consumption.  At times when the
> inverter doesn't cover 100% of your load, you pull from the grid.  If
> you're lucky, you have net metering so you get credit for any excess
> you put into the grid.

Which is nice but not a necessity and would not be my primary reason for 
solar in the first place.
Any system I put in has to be capable of at least powering my house for 
at least 24 hours.

> Regardless, whether there are batteries or not, UL requires that
> grid-tied distributed generation systems (solar, wind, hydro,
> whatever) disconnect from the grid within a cycle or three (forget the
> actual spec).

It would have to do that any way for self preservation and a transfer 
switch can do that.
If my transfer switch did not operate can you imagine how long my 
generator would last trying to power everything in my neighbors homes?

>    This is to protect utility workers and the integrity of
> the grid.

Disconnect is fine. I have to do that even with a generator. OTOH the 
way they do it,  to me defeats the entire purpose of of why I would 
install solar.  I need a backup system. Although the money back from the 
utility would be nice, it would not be my primary goal. As I would be 
using large batteries as storage,  I'd have to develop a work around 
plus another inverter to keep AC power in the house during one of the 
many failures.  Such systems are advertised but I've never had the 
chance to view one or check it for RFI.

I want a system that will provide substantial power and back up the AC 
system for at least 24 to 48 hours.  Yes, I know how much that costs.  
I'd prefer independence, but back up would suffice.

The major problem with these systems is cheap inverters and RFI. There 
are good systems and many not so good. Fortunately  not many of the not 
so good are next door to hams. OTOH we have had posters with noise 
problems from nearly a mile away.   The inverters at the PV panels 
require some pretty good protection from lightning. Transistors are 
fragile, and it wouldn't take much to turn a quiet system into a real 
noise maker.

My tower has been up since 2001 and taken 17 verified direct strikes.  
How many it actually took I have no idea.  For the first 5 years it 
averaged 3 a year. Year # 6 it took one hit and none since then...that I 
know of.  I wonder how well roof mounted inverters (at the panels) would 
have survived that and if they would have kept producing clean power? 
OTOH that may not be much of a concern as they have outlawed (at least 
for the time being) solar installations in our township due to 
complaints caused by reflections from the last system installed.

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