Hello wrenches and Marv:
How many Enphase inverters do you put on a single parallel string? The
Enphase manual allows for up to 15, but I have found that a single string of 15
can have very high voltage rise on the AC wiring. Up to 1.5% loss just on the
Enphase cables, and that does not ta
Nick,
Good to see other wrenches looking at this issue. However, remember that
in the interconnect cable between the last and the second to last Enphase,
the current is small. If you really want to see how the loss is adding up
you need a more detailed analysis that averages the voltage drop for
Our customer, an engineer in San Diego, self-installed 28 KC120 modules in
2002. May 25, 2010, he reported that the array output stopped. The same day
I emailed him that his test results indicated that the problem was bad cell
interconnects, that Kyocera knew of the problem, did not recall the m
Hi Nick,
You bring up a good point that Enphase should address more clearly.
However, I think the math should be done section by section to accurately
account for the wire loss and not the total combined amps for the entire length.
If the loss's are too high then reducing the number in each strin
Joel,
Thanks for the information. 35% loss due to to smog or soiling is a
big hit and, I'm sure, an exception. Still, if the loss is even 20% it
supports the concept that an array here on the cool, cloudy west side
of the WA Cascades can perform on par with an equivalent array in a
hot, du
Did you notice that in my calculation I divided the total amperage by 2 to get
the average ampacity across the string. This seems to be the best way to deal
with that. Otherwise the loss would have been over 2.8%
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 65
Maybe Marv can help out here. I¹ve talked with tech support at Enphase and
am under the impression that you can center tap their branch circuits to
reduce voltage drop. This technique was used on a project that we profiled
in SolarPro:
http://solarprofessional.com/article/?file=SP3_2_pg92_Projects
I guess all this does is effectively reduce the number of inverters in each
string, and create two strings from one (but without additional homerun
string wiring). So you need two factory pigtails instead of one for each
"original" string for the center tap j-box, but a small price to pay for
incre
Anyone have any line on some MC4s or have some, even a paltry quantity, that
they're willing to part with?
Thanks,
marco
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Kelly,
Your area is a prime example of needing to find a data site that is not
geographically closest, but climatically closest. In Washington, the
microclimates are so extreme, that data from PV:Watts must be manually
selected. It is not because the program is that far off, it is the climat
Joel and All,
PV:WATTS is just a very simple simulation. You can make simple corrections
for temp coefficient if you like, but if you want better accuracy, you have
to go to a more sophisticated program like PVSyst or PVSol.
Bill.
-Original Message-
From: re-wrenches-boun...@lists.re-wre
We did a 6 kW system 6 years ago using 160 watt, 160 watt modules, and the
client recently called back and asked us to add another 4 kW.
We no longer install this brand of module and have lost track who in US
supplies them. We found them to be well made and look great, but we just
started usi
I just attended a training class in Philly last week by Enphase technical staff and my notes say they suggest up to 15 micro-inverters @ 190 watts each per string with no problem. They also are now shipping their dual module micro-inverter which should help with this wire issue since this model #D
Title: Re: [RE-wrenches] AC wiring loss on micro-inverters
Nick,
Sorry for the delayed reply. I've been traveling and am just catching
up on e-mails.
Your method is absolutely correct. We're working on an appnote and a
calculator to provide you guys with some quick tools.
David also brings
Hi fellow wrenches forgive me if this has been said.
The AC is a special problem on MIcro inverters because the long runs modules to
service are now in the AC section of the system. The DC connections are very
short. The utility has a +- 5% normal tolerance, which leaves us with only 5%
to co
I have maybe 50
DT
--- On Fri, 6/11/10, Marco Mangelsdorf wrote:
From: Marco Mangelsdorf
Subject: [RE-wrenches] desperately seeking MC4 connectors
To: "'RE-wrenches'"
Date: Friday, June 11, 2010, 4:58 PM
Anyone have any line on some MC4s or have some, even a
paltry quantity, that
Just my two cents worth, from measured data we get about 1250 kWh per watt in
Minnesota per year this is measured over roughly 8 years, I had more trouble
with the monitoring system than the array. The winter measured lower than
predicted, and the summer measured higher. The winter is easy to
Hi gang. If you have a comments on this post, please contact me off list.
Some time ago we decided we should allow requests for hard to find products and
replacement products on the list.
This has me a bit worried, specially as systems become older and products
damaged by weather etc. need to
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