Hi Andrew,
Thanks for your information on the XW Series. It seems that there
were a lot of problems when they first came out. Many of the
problems may have been due to mis programming.
Do you think the XW4024 is good replacement for the old SW4024? With
AC 1 in and AC 2 in, reliable gen
Hi Larry,
I was under the impression that Sunpower were only for on grid?
And for off grid with the low voltages that we use, they are still
requiring you to use positive ground? I've seen the white paper they
did and it showed at lower voltages there is no need to positive
ground, thats
William,
We have used the SPR-90 and CTI-90 with Blue Sky, Outback and
Morningstar MPPT controllers. No issues, no problems. Be aware that
most of our installs are RV's and trailers and not grounded. We have
installed them in grounded systems in Mexico. The CTI-90, rated at
5.15 amps, wil
Sunpower modules can wired 2 in series for the 200 watt 72 cell modules
and 4 in series for the 90 watt 32 cell modules with typical negative
grounding. The power loss effect is not a problem in low voltage
systems. AEE Solar has private-labeled modules for battery charging,
made with Sunpowe
At 09:46 AM 3/20/2009, you wrote:
The CTI-90, rated at 5.15 amps, will reach 7 amps here in Yuma with
the Blue Sky 3024i.
Do you use the Blue Sky metering, or have you checked the MPPT output
with independent metering? I retrofitted a 12 V Blue Sky charger on
an old cabin system. The CC had
Drake,
The key to your question may be in the "old Arco units". Most Arcos (all
predate 1990, when Siemens bought Arco) are 36 cell, but both Arco and
Solarex made some 33-cell, 32-cell, and even 30-cell "self-regulating"
modules in those years. With fewer cells, the MPPT was too low to benefit
muc
Drake,
Just to add to Allan's excellent post, most of the Arco's made before about
1985 had less than 36 cells. Some were 35-cell, most were 33-cell, but there
were also 32 and 30-cell units.
You might want to look into rewiring the modules in higher voltage series
strings to get more "oomph"
Allan and Brian
Thanks for the answer to the problem. I think the Xantrex PWM
chargers are going to be the most appropriate for these modules.
The old Arco modules are incredibly long lasting. I hope the ones we
are putting in today will last as long.
Drake
At 01:40 PM 3/20/2009, you wro
Drake,
One thing about those old modules is that the cells are incredibly thick. You
can feel them on the back-sheet. They must be at least 1/16" thick. Wire-saw
technology was just not that good in the old days. Module manufacturers say
that the thickness of the cell has no effect on performan
Drake,
I have seen this often. The operating voltage drops as panels age.
MPPT depends on a higher input voltage compared to the battery
voltage. When you account for module temperature and age, the panel
may not produce enough differential voltage for the controller to
convert into power
Word of caution... don't wire the bigger SunPower modules with the
negative conductor grounded. With the metal frame grounded, as it
should be, this combination causes a strange surface polarization effect
that will discolor the cells and cause the power output to drop by about
half. Fortunately
Arco Solar used inside diameter (ID) saws to cut wafer 3 mils (0.003 inches)
thick. I don't recall when Arco got wire saws. Solec also used ID saws until
1995. See http://dove.eng.sunysb.edu/~kao/Wiresaw/NSF-97.pdf Thinner cells
and wire sawing yields more kW/kg but require better handling equi
Jeff,
Although some of what you say is true-and anyone allowed to install SunPower
modules should be intimately aware of the positive grounding
requirement-they actually can be installed on ungrounded and bi-polar arrays
with the inclusion of some wiz-bang depolizerinators ;-).
Bottom line
Joel,
My understanding is that some of the manufacturers are able to cut so thin
with current wire saws that the cells become flexible--almost like paper. It
presents other concerns, but these newer technologies might actually be
solving some of the cracking problems of the past. It is a brave new
Thanks for the flowers, Drake and Brian.
Yes, I'd use PWM without MPPT. We have long jokingly referred to the C40 as
"our best selling used charge controller" because of how many we removed
once reliable MPPT units (the RVPP/now Blue Sky SB series) hit the market.
It was a cost-effective upgrade f
Although some of what you say is true-and anyone allowed to install SunPower
modules should be intimately aware of the positive grounding
requirement-they actually can be installed on ungrounded and bi-polar arrays
with the inclusion of some wiz-bang depolizerinators ;-).
Bill, you need a b
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