On 3/21/2013 9:59 PM, Exeltech wrote:
Wrenches,
I'm probably a lone voice on this .. and not intending to get overly
picky.
No, two lonely voices, Dan.
I associate clipping with audio waveforms which stops
the negative or positive voltage peaks flat. Also called
flat-topping.
Limiting
Hi Dan,
A very heartfelt thanks for the education.
It is exactly this kind of attention to detail that separate the
professional from the practitioner. Moreover, at least in this case, the
proper terminology is hopefully better and more widely understood.
Thanks again,
Bill Loesch
Solar 1 -
Hi boB,
Kudos to you, too. Flat-topping (bottoming) is so very descriptive and
hopefully universally understandable. Excellent analogies.
Technical education/expertise sharing is one of the most prized benefits
of belonging/participating on the RE-wrenches list.
Thanks,
Bill Loesch
Solar 1
It depends on the type of metal shingle/tile, of course, but many of them
have a screw where they overlap. We are seeing a lot of the simulated round
tiles that are made of metal, and they can have a screw at the apex near
the overlap, or on the overlap/edge.
*Jason Szumlanski*
*Fafco Solar*
It would be good to quantify the amount of peak
energy that is lost through power limiting. We
have a 2160 Watt array on a 40 degree pitched
roof with a SB 2500HF US inverter. The other day
I watched the meter hover over 2000 W and peak at
2490 W. It was a clear, cold day. It runs in the
STC
The power quality should not be adversely affected.
While I'm sure different manufacturers may limit power in different ways, in
theory all the inverter is doing is moving the array off its MPP. Here's a
description from AE:
If the power available from the array exceeds the nameplate rating
Good points David, we are in peak season for inverters to be limiting
power.
Marco, your diagram shows that the modules are only overproducing the
Enphase M215's output of 225 watts for a single 15 minute period during the
day. That would only equate to about 3 watt-hours of lost power on a day
Hi Jesse and Wrenches,
One thing that should be understood about the production readings from a DC
optimizer system is that the module level readings are in DC. That is the
production before being converted to AC, and does not account for the
losses of the inverter. It isn't really an apples to
We have an older Windows XP based laptop that we used for years for inverter
and array commissioning that also ran the XW configure software tool using a
USB software driver for the Xanbus Diagnostic Tool. However, like all
computers, just when you get them to run all the software you need, they
Jeff,
We've only done a couple of XW systems, but when I needed software
I was able to have it emailed to me by XW tech support. If you
don't get a response here, you might try that.
Allan
Allan Sindelar
We have an Xantrex XW 6048 inverter we installed for a client about 2 years
ago that includes the separate generator control module, which currently
programmed to start the generator on low battery. The client has gone
through several outages when he was not home. The solar/battery/inverter
Understood. I guess the point/question was, a 250W module with a 215W micro
would flat top a heck of a lot of power where I live during the 6 months of
winter we have. I've sized my system to account for increased production during
this time. I guess it comes down to sizing. I find it hard to
We now have 230W, 235W, 240W, 245W, and 250W modules on Enphase M215's in
the field. Initial anecdotal evidence shows that the 250W modules are doing
better in our area, even when the cost comparison is taken into account
(normalized for $/watt). I don't have a full year of data yet, but I plan
to
Interesting. Jason you're in FLA right? I'd like to hear from a northern
installer who's put in a similar group of enphase. That's exactly the type of
info I'm looking for. Like you mention, this might all be a waste if time when
you consider module price. I'm having a hard time getting
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