Hi Matt,
I use the Solar World 175's, very happy with them.
Also use, Evergreen and have tried the new REC but don't have any good
feed back on they yet as to how well they do.
Most all my systems use a stepdown controller, and I can get away with
3 x 24v modules in series due to my low temperatures here.
I wonder how much longer they will be around.
jay
peltz power
On Dec 10, 2008, at 2:54 PM, Matt Tritt wrote:
My favorite is the Sharp 175 for off-grid and solar pumping
applications; a sturdy, well built and consistent module for most
applications. You can even get them fairly often!
Matt T
Kirpal Khalsa wrote:
Allen..Greetings....yes indeed it is an issue. we have been
addressing with multiple charge controllers per system. we don't
fight the current (not electrical). In the future the way i see
it- the electronics will be more flexible and be able to handle the
larger variety of string voltages. For example the long long long
awaited apollo solar t100 which will allow voltages to exceed the
150V limit we have had for a long time. They have apparently even
lined up some breakers which will work with these greater
voltages. 3 modules in a series will no longer be a maximum. I
understand midnite solar also has a charge controller which will
allow the 150V max to go by the way side. We are trying to be
flexible as modules become less standard and hope that the
electronics will allow us to address thesee challanges as time goes
by.
One thing that we would love to see is more large wattage modules
with j boxes rather than pre-wired MC cables. In many of our off
grid systems the array is located in readily accesible locations
and crafting a fence or sticking the array over 8 feet of the
ground is a big hassle/extra expense. This has proven to be a
bigger concern for us rahter than the voltage variety. If you know
of any 72 cell or for that matter 60 cell modules which allow flex
conduit between j boxes we would love some info.......
--
Sunny Regards,
Kirpal Khalsa
NABCEP Certified Solar PV Installer
Renewable Energy Systems LLC
On Wed, Dec 10, 2008 at 12:16 PM, Allan Sindelar <[EMAIL PROTECTED]
> wrote:
Wrenches,
Here's an issue I haven't seen directly addressed, and I would like
to know what the rest of you are doing.
It's getting harder to get 24V nominal modules. Because the bulk of
industry growth is high-voltage grid-tied applications, modules no
longer have to be a standard voltage. Just pick the number of
modules to best fit the chosen inverter's string voltage range.
But for off-grid, the odd cell counts and resulting
"nontraditional" DC input voltages challenge the traditional rules
of off-grid design. I may be fighting a losing battle here, as the
industry changes so rapidly and fundamentally. I have been trying
to stay with 72-cell modules for offgrid, as this most readily
combines with existing systems with 36-cell modules (12V) and 72-
cell modules (24V).
For example, I will use the new Canadian Solar 170-200W modules.
They are 60-cell modules, with a Vmppt of around 28 volts - too low
to charge 24V batteries with a standard charge controller. We can
use them in any new systems with an MX60 or similar voltage-
converting MPPT controller. Two or three in series would charge a
24V battery; 3 in series would charge 48V. Four in series would
violate Code, as low-temp voltage would easily exceed 150V.
Unless 60-cell modules remain a standard in the future, any future
array additions would have to be on their own charge controller, in
order to match a different I-V curve and MPP voltages into the same
battery bank. Is this prohibitive? No, it just runs counter to the
longstanding standards of off-grid design that allow modules to be
added in the future: these modules will not add well to existing
systems, and will not easily allow additional dissimilar modules to
be added later.
I had this same objection to using Day4 modules, although they were
better at 16Vnom. Three made up a standard 48V array, so strings
could be combined with two-module strings of similar 24Vnom modules.
Who else is trying to stay with 24V modules? Anyone still using 12V
modules in off-grid (residential-scale, not little apps) designs?
Who has a crystal ball and knows what modules will be like in 20
years, or even two years? Wat are the rest of you doing?
Thanks, as usual.
Allan
Allan Sindelar
allan_(at)_positiveenergysolar.com
NABCEP certified solar PV installer
Positive Energy, Inc.
3225A Richards Lane
Santa Fe NM 87507
505 424-1112
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