Peter,
Not to belabor the issue, but your understanding of the I-V curve and how it
responds to changes in irradiance and temperature are flawed. I'm sorry you
believe that I am misleading you, but the truth is that the I-V curve moves
up and down with changing irradiance (current changes with irr
Kent:
Good points. Enphase may allow us to disconnect their DC connectors under
load, but each of their connectors mates with a connector installed at the
PV factory. The module makers usually say don't disconnect under load. So
the inverter and the PV listings both need to allow disconnect
Marv,
The manual now clearly states that the ac and dc connectors have been
evaluated and approved for use as the required ac load break
disconnect. Yet in other locations the manual still says "Never
disconnect the DC wire connectors under load" and "The AC connector of
the first microinvert
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Thursday, May 20, 2010 7:12 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Two strings of Different Orientation
Peter,
The issue is th
Kirpal,
None of the SQFlex equipment is UL listed. You may find that your AHJ
won't approve any of the SQFlex controls and possibly not even the pump.
Kent Osterberg
Blue Mountain Solar
Kirpal Khalsa wrote:
Hi Folks.I am working on putting together a domestic
water pumping system using
Peter,
The issue is the same as it was last year. The operating voltage of each
string will be nearly identical throughout the day if the strings are the
same length and not shaded. Put them on a single inverter.
The Fronius report was not discussing a special algorithm for dealing with
this situ
Kirpal,
Lots of good suggestions so far here, but here's my take:
Unless there is a very high water need during the daytime hours, most of the
time the PV array will be sitting there just doing nothing, which is what
happens in most pressure systems. You would be better off just using an AC pum
Good points, Allan & Ray~
I think Rays caveats can be mitigated depending on the wattage of the
solar module relative to what the coil requires. If the 17v solar
module is somewhat oversized it will run closer to its open circuit
voltage which would make it more likely that a 24v relay coil would
I think you're going to have trouble with the array direct to the relay coil. a
12 v relay may burn long term, as suspected, but the 24 v relay probably won't
close reliably at the lower voltage.
R. Walters
r...@solarray.com
Solar Engineer
On May 20, 2010, at 3:37 PM, Mick Abraham wrote:
>
I believe Allan's suggestion won't work because the utility AC is
present so the system cannot use PV unless there's a grid
blackout on a sunny day.
Dan's suggestion sounds more likely: a "double pole double throw" DPDT
relay which requires DC for the coil.
Consider devoting a small 17v PV modul
Kirpal,
I did this about 5 years ago, on an array-direct irrigation pump with
the ability for the client to run a generator when needed. Yes, it's
all automatic, and no additional relay is needed. When the IO101 senses
AC it automatically closes a contactor - AC coil, NO is the AC, NC is
the PV
Subject: NABCEP Announces New Level in PV Installer Certification Program
Reply-To: i...@nabcep.org
NABCEP Announces New Level in PV Installer Certification Program
CLIFTON PARK, NY, May 20, 2010 - The North American Board of Certified Energy
Practitioners (NABCEP) announces new credentialin
Ironically as I was looking through my TED 5000 package this thread came
through.
I am looking to use the TED for data logging for an off grid project, and
plan on connecting a computer directly to the Gateway, as the client doesn't
have internet access. I hope to use the information for system s
As you know, the TED uses a Power Line Carrier communications scheme where
data is impressed on the 60Hz AC waveform for distribution throughout the
house. There are many pitfalls in this method of data comms, but it can be
done and be reliable.
That being said here is my experience with the TE
Could be as simple as installing a DC relay of appropriate coil voltage and
contact configuration & ratings. Then, use the PV to power the relay and the
contacts to select your preferred power source. The necessary hysteresis
inherent in relays would be present. Select a relay for the environ
Hi Folks.I am working on putting together a domestic water pumping
system using a grundfos 11 - SQF - 2. This system will be connected to a
standard pressure tank and cistern and have a solar array providing primary
power. However at night and on cloudy days we would like the system to
switch
I was intrigued by a previous thread on Google Powermeter and the TED 5000 and
tried to setup on two system.
In both cases, they did not work. I know they were installed correctly and
factory support has me moving wires, getting noise filters, using different
branch circuits, etc. In other wo
sounds like a great situation for tigo power optimizers we should be seeing
pretty soon.
nick vida
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Wrenches,
Please note that Enphase has completed testing and received listing for
the ac connectors and the DC connectors for use as the disconnect as
required by the NEC. No other disconnect device is required. This
information is contained in the latest Installation and Operations
manual,
WOW Chris I have always held great respect for you,is this for real
Those spring time winds haven't distorted your sense of reality? You sure
that you are dealing w/ the same SUMWIZE that I tried to deal w/?
NO personal interaction w/ my "sales person" It seemed that they wanted to
have me buy
Good point. I use a "mixing valve" to prevent overtemp water (165*+) from
flowing into my propane hot water heater/storage tank, this prevents the
overtemp safety plug from going.
& then a "Anti scald" valve to condition my water to 110* on the outboard
side of the propane hot water heater/sto
This is per our AHJ.
Thanks,
Dana Orzel
Great Solar works, Inc.
E - d...@solarwork.com
V - 970.626.5253
F - 970.626.414
C - 970.209.4076
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of benn kilburn
Sent: Wednesday, May
How about a nice Power-One Aurora inverter with two MPP string inputs?
http://www.power-one.com/renewable-energy/grid-tie-solar-inverters.php
-Glenn Burt
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Pet
Hi Bill,
The valves are the AM-1 series. I wasn't aware that these incorporate
check valves. In fact, we have had problems in some systems having HW
recirculation with the hot circulating back through the cold supply,
causing us to install separate check valves in the cold lines (which
we
Abut once a year we encounter this problem and each time I reach out to
folks for guidance. Up until last year, I don't believe that there was a
readily accessible tool that accurately simulated the behavior of "two
strings of modules with different orientations". PVSyst is too expensive and
hard t
Randy,
These valves are the Honeywell Sparcomix AM series, which are
certified for "anti-scald" (ASSE 1016 & 1017)
The specs show that, for a hot supply range of 120˚ to 180˚, at a
position #2, the mix temp should vary only from 116˚ to 122˚. The
valve is definitely not working to spec, and
Doug,
I HAVE had tank (SS) temps in excess of 180˚, but rarely. These valves
are the Honeywell Sparcomix AM series. I don't see any temperature
limitations listed in the specifications.
-Kelly
Kelly Keilwitz, P.E.
Whidbey Sun & Wind
Renewable Energy Systems
ke...@whidbeysunwind.com
360-678-7
Bill,
The water is quite hard (30 grains/gal), but there is a softener on
the DHW that lowers the CaCO3 level significantly. I thought that
this might have been a contributing factor with the previous mixing
valve, but replacement (~2 years ago) didn't address the problem.
Other than hard
Subject: NABCEP Releases Small Wind Installer Certification Application Ahead
of the September 2010 Exam
Reply-To: i...@nabcep.org
NABCEP Releases the Small Wind Installer Certification Application Ahead of the
September 2010 Exam
Clifton Park, NY, May 19, 2010 - NABCEP
The North American B
Hi again, Kelly,
You mentioned backflow issues in your post, which I should have addressed
with my previous reply.
If the Honeywell valve you are using is a Honeywell AM-1 Thermostatic Mixing
Valve it incorporates dual check valves on the inlets. Those check valves
are removable and those check
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