Hello, Wrenches~
Please see the photo on page 48 of the latest *Home Power* magazine (#138).
This shows aluminum fins with an extruded clip into which Rehau type radiant
floor tubing can be clipped.
Where can I get these parts for resale?
Have any of you observed an installation where this
I should have been a bit more clear about my application. I'm not
worried about battery charging rates or load percentage on the
generator. I've already determined that this size generator will
normally run at a good efficiency level. I am more concerned with the
quality, longevity, and enclosure.
Darryl:
There is a scenario in which problems occur: If your loads exceed the
generator capacity, the Outback system will fail. The Xantrex inverters
are superior in this scenario in that they will transition to invert mode
to synchronize with the generator and support the generator as long
Folks,
I have three strings of batteries cabled in parallel to a common buss bar.
During charging, one string takes significantly less current than the
others.
What can I infer from this? Is the low current string healthier, presenting
higher impedance due to a higher state of charge? Or is
Mark,
Do the interconnects total the same length in each string? There could
be a bad connection somewhere in that string. But more than likely
this behavior is the result of a cell (or cells) that has a high
impedance because it is sulfated. How do the specific gravity numbers
look.
Kent
try disconnecting all strings from each other... (check all electrolyte levels and Specific Gravity).. let them rest for a while... and compare individual battery voltages... you're looking for about 2 volt differences... (bad cells)... basically you're up against an ohm's law thing...
When calculating the voltage drop from a PV array to the inverter, what's
the most common accepted practice? To use the Isc X 1.25 or 1.56 as the
multiplier?
Thanks,
marco
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Most appropriate is Ip-max. If you are operating @ ISC or above, your voltage
has already dropped to zero... AKA 100% voltage drop.
Pray for Sun!
Matt Lafferty
- nbsp;Sent from my Palm Pre
On Jul 22, 2010 12:22 PM, Marco Mangelsdorf lt;ma...@pvthawaii.comgt; wrote:
When calculating the
I use actual operating current, without multipliers. I also use actual
temperatures, not the worst case temperatures that many use.
I created a spread sheet that uses the NEC adjustments for wire temperature,
(see NEC chapter 9, table 8, FPN 2)
It makes quite a difference!
Volt drop and the
Hi All,
I agree with Ray with the exception that I use Imp*1.25 in my calculations.
I developed a simple spreadsheet for either fixed conductor size or for
fixed voltage drop. You can feel free to use it by downloading here:
Greetings all,
When the subpanel is fed with 380A wire and the OCD is 400A and the panel
bus is 400A, which number would be used for determining 120% capacity?
I'm thinking the 400A because the bus would be overfed before the wire?
So if we want to land 225A of OCD for solar output on the line
For array to power center or Inverter; I use 125% of amps @
max power and run the wire calculations at 1% VD.
We have set Fluke meters on clamped on @ both ends and
talked with radios compared the readings. We have not seen
any noticeable VD down to .00vdc.
Perhaps overkill?
Thanks,
OK,
So no takers for the low current string being in a healthier, higher state
of charge!
Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
http://www.berkeleysolar.com/ www.berkeleysolar.com
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Mike,
Why do you make this exception, please?
Allan Sindelar
Allan@positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Hi Dana;
I'd say that's a bit overkill for today's market. That money could be making
more power, not just preventing losses.
Definitely a law of diminishing returns on wire sizing.
If you allocated 50% of the budget to wire, and 50% to PV, your losses would be
very low, (immeasurable but
Mark,
If you had one healthy string connected in parallel with two weak strings,
the tendency would be for the weaker strings to pull the stronger string down
to their level. It's more likely an impedance issue in the string with the
lower current. All other things being equal, look for bad
Mike,
I would respectfully challenge both reasons ;^)} . The responses
already posted today cover them: you don't need to compensate for
intermittent high-insolation conditions when sizing for voltage
loss, as this is not a Code issue; Code addresses ampacity and OCP
Hi gang. Just a quick note. It has awhile since Christopher was with Outback.
Steve Higgins is the Outback manufacturer representative on the list.
Dana wrote at 08:36 AM 7/22/2010:
Chris Freitas of Outback can you chime in here?
Thanks, Dana Orzel
Ray,
The $ could be making power I agree on a large scale project.
The point here is where is the cutoff point?
Let’s take a very small cabin system:
410 watts or 13 amps [inc.1.25%]@ 44VOC, over a 90’ one-way run.
Utilizing and Electro-calc with 2008 NEC installed
2.6%VD –
All,
This is all very interesting, but on the dc side, it is primarily an issue
of energy loss for large grid-connected systems. My rule is 2% voltage drop
for dc side and 1% for ac side.
When we talk about dc % voltage drop, most of what has been discussed in
this thread is instantaneous
Finding that wire in these here parts is pretty much impossible.
Can any of my CA. brethren/sistren provide me any leads on wholesalers in
either northern or southern CA. that carry #10 THWN-2 wire?
Thanks,
marco
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I have used this approach with 1/2 inch nom. copper tube, it works. The
Aluminum I got form New Jersey Aluminum, they sold out to another company. I
am not sure it is made any more, but I had a custom extrusion made for me for
about $3000 I have also seen a thin folded AL fin from floor heat
Dana,
2.6% voltage drop also means 2.6% power loss. To go from 2.6% loss to
1.6% loss you gain about 4.1 watts for the extra $22. That is
$5.36/watt so it probably makes sense to use the larger wire. Now
compare 1.6% and 0.4%: you gain about 4.9 watts for the extra $140,
that's $28.57/watt.
I am talking with a customer who wants to do a standalone system using an
Endurance wind machine, solar, and genset. I have no experience with
Endurance other than to know it is a good machine. Talking with Magnum today
they informed me that the MS 4XXX PAE inverter, combined with the ARC
Marco,
The #10 THWN wire that your local suppliers carry may be cross-listed as
THWN-2. My understanding is that it is not uncommon for smaller gauge wire
to carry more listings than are printed on its insulation. (If that¹s not
true, we¹ll find out shortly from someone on the list.) If your
THWN-2 smaller than #8 is hard to find but I hear
http://www.encorewire.com/site_flash/index.html makes it and that
Graybar sells it. When I asked Southwire about it about two years ago, I
got a collective huh?
Original Message
Subject: Re: [RE-wrenches] #10 THWN-2
From:
Marco,
I found the same situation as what David mentions -- when we were doing a
high profile job that was going to be inspected by a certain someone from
Las Cruces, all the wire available from local suppliers was only physically
marked as THHN / THWN, but when we dug a little deeper and found
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