Thanks to everyone for your responses, both on and off-list. You guys rock.
Allan,
The system was originally installed in 2000 with an Ananda
controller/disconnect box. The giant one with the mercury relays. It failed
about 6 years ago and an MX-60 was installed to replace it. I agree that a
mo
Luke,
I deleted your first message, but I thought you wrote that the
system was pre-MPPT, with strings wired as 4 12 Vnom in series. IT
seems to me that given insufficient Vmp, a modern controller is a
no-brainer anyway, and it's only a matter to which one to use.
I agree, scratch my previous suggestion of 8 in series on the Outback
controller. I got so used to Midnites that I forgot how unforgiving
the Outback controllers are with high Voc. Run the Unisolar modules
through the Midnite sizer. http://www.midnitesolar.com/sizingTool/index.php
R.Ray Wal
Allen,
With 8 modules in series I think I'll be looking at a Classic 250 for sure to
be comfortable with winter morning VOC.
I don't really know what kind of combiner situation I'll find up in the attic.
It may be easy enough to re-wire into strings of 6 instead of strings of 8,
though that is
Jay,
the 71V I measured was the array VOC.
Accessing the wiring for individual strings is fairly difficult as the
combiners are high up in a hot attic. I didn't have a lot of time on site the
day I observed this problem, so didn't gather as much information as I could
have otherwise.
A re-wir
Jay,
Whoa, I'd be careful there. Unless there's been a change while I was
away on my bicycle, Outbacks are still 140V rated maximum voltage
and 150V hard maximum. 142Voc in May suggests that doubling strings
in series will easily exceed max Voc in winter. That's why I
One solution is to restring up to the max of the outback, say double what
you got now, easy to do on the combined. This will not change the fact of
cause that the modules are molding some of the power but will get the input
voltage up where it needs to be
Jerry
On May 31, 2015 4:03 PM, "Randy Brook
I second Jay. If one string is significantly lower, I’d check each module in
the string. Could be a bad module.
Randy
> On May 31, 2015, at 1:23 PM, jay peltz wrote:
>
> HI Luke,
>
> To add here. I'm unclear if you have measured each string or the whole array
> at 71v.
> I would check e
HI Luke,
To add here. I'm unclear if you have measured each string or the whole
array at 71v.
I would check each string for voc/isc.
And then if they are consistent, I agree that putting 2 strings in series
with a new controller might help out.
You can try it with the MX-60 as you are at only 14
I have a new client in ID that has the same product. The 48 volt system has
a relay style era charge controller that we will upgrade this summer. He has
no issues achieving equalization voltages PV direct without the generator.
For a product that had a lot of press in the early days this is only th
Ive installed a few systems with these laminates years ago, but havent kept
up with performance much unfortunately. I have heard of the diodes going
bad (which are glued into the laminate along the sides). Maybe thats your
issue? Just speculating...
Roy Rakobitsch
NABCEP Certified Small Wind Inst
Luke,
I have never worked with Uni-Solar laminates, although I expect to for the
first time this summer, at 12,800' in the White-Inyo mountains, but that's
another story. I installed one small cabin system with US64s in 1999 (the
rancher wanted modules that would keep performing with a few vanda
Yes, amorphous modules degrade faster then crystalline cells. 15 years
will really start catching up with you, that's why we always tried to
stick to monocrystalline when we could.
I think your best option for now is to rewire the array for much higher
voltage. Even your current voltage problem
Hello Off-Grid Wrenches,
I recently made a periodic maintenance visit to a residential off-grid system I
take care of here in Southern CO, and discovered an interesting problem.
This system has an array of 48x Uni-Solar PVL-68 laminate modules applied
directly to standing-seam metal roofing.
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