Posted by Richard Nelson on August 1, 2018, 6:19 pm
On Wed, 1 Aug 2018 13:50:56 -0400, "Jim Wilkins"
>This is a pretty good deal, with free home delivery:
>https://www.homedepot.com/p/Grape-Solar-100-Watt-Polycrystalline-Solar-Panel-for-RV-s-Boats-and-12-Volt-Systems-GS-Star-100W/204211365
>They are 36 cell panels good for 12V or 24V lead-acids with PWM
>controllers, I don't know how they would do as a high voltage series
>string with an MPPT controller. They handle partial tree trunk shading
>pretty well. If your array can be partially shaded there are
>distributed MPPT and inverter topologies that increase output, and
>initial investment.
>
OK, thanks. I am anticipating purchasing qty. (48) 300 - 330w panels
and right now I am expecting to use string inverter(s). As I said
previously, the array will be ground mounted but not a tracking array.
I will throw out my questions again for anyone else; can anyone
recommend some decent reference material on the entire design /
installation process? I have the NFPA 70 / NEC and the NEM from my
utility provider. I have been reading Home Power magazine, any other
sources would be appreciated.
Posted by mike on August 1, 2018, 8:48 pm
On 8/1/2018 11:19 AM, Richard Nelson wrote:
> On Wed, 1 Aug 2018 13:50:56 -0400, "Jim Wilkins"
>
>> This is a pretty good deal, with free home delivery:
>> https://www.homedepot.com/p/Grape-Solar-100-Watt-Polycrystalline-Solar-Panel-for-RV-s-Boats-and-12-Volt-Systems-GS-Star-100W/204211365
>> They are 36 cell panels good for 12V or 24V lead-acids with PWM
>> controllers, I don't know how they would do as a high voltage series
>> string with an MPPT controller. They handle partial tree trunk shading
>> pretty well. If your array can be partially shaded there are
>> distributed MPPT and inverter topologies that increase output, and
>> initial investment.
>>
>
>
> OK, thanks. I am anticipating purchasing qty. (48) 300 - 330w panels
> and right now I am expecting to use string inverter(s). As I said
> previously, the array will be ground mounted but not a tracking array.
>
> I will throw out my questions again for anyone else; can anyone
> recommend some decent reference material on the entire design /
> installation process? I have the NFPA 70 / NEC and the NEM from my
> utility provider. I have been reading Home Power magazine, any other
> sources would be appreciated.
>
I don't think your biggest problems will be technical.
First thing I'd do is have a discussion with the local building
inspector.
The local folks and the NEC are not always in sync. I've had the
inspector tell me he'd approve electrical stuff that was clearly
disallowed by the NEC. Same guy failed a professionally installed
AC power circuit because the breaker didn't have the right sticker.
Find local solar installations and knock on the door to get
real opinions.
Examine your payback spreadsheet to make sure you've included
potential changes in what the 'grid' pays for electricity.
If you're counting on any 'assistance' in the form of
solar rebates or tax cuts or other incentives, make sure
you understand whether they'll be there in a few years.
I had a vendor try to lease me a solar system that had very
attractive numbers based on available 'assistance'. Closer
examination revealed that the future of the government
assistance program was uncertain.
You had to renew annually on one date.
The available funds were limited
and were gone within milliseconds of the opening bell.
If you didn't get one, you were screwed.
Talk to your insurance company and decide how you're gonna
keep people from stealing your panels...or vandalizing them.
I have no experience with grid tie.
All I've done is MPPT controllers, battery management
and sun tracking for small
12V mountain-top radio repeaters.
It's likely that the choice of the part that ties to the
grid will dictate the rest of your system.
15KW can be a lot of amps. Get whatever the panels produce
converted to the highest voltage in the system as close
to the array as possible.
Leave enough space between panels so you can clean them
and cut the weeds.
START SLOW. Deciding that you made the wrong choice
is painful AFTER you've got 48 panels.
Posted by Jim Wilkins on August 1, 2018, 9:27 pm
> ...
> I have no experience with grid tie.
> All I've done is MPPT controllers, battery management
> and sun tracking for small
> 12V mountain-top radio repeaters.
>
What has your experience been with the batterys?
-jsw
Posted by mike on August 1, 2018, 11:10 pm
On 8/1/2018 2:27 PM, Jim Wilkins wrote:
>> ...
>> I have no experience with grid tie.
>> All I've done is MPPT controllers, battery management
>> and sun tracking for small
>> 12V mountain-top radio repeaters.
>>
>
> What has your experience been with the batterys?
> -jsw
>
>
I don't deal directly with the installation. All I hear
are complaints about the cost of good batteries.
It's easy to outrun the available sunlight in winter.
System has to be shut down to prevent overdischarge.
Typical system is a combination of solar and wind.
Had to resort to a shunt regulator to prevent
runaway of the wind generator.
Posted by Richard Nelson on August 1, 2018, 9:51 pm
>First thing I'd do is have a discussion with the local building
>inspector.
>The local folks and the NEC are not always in sync. I've had the
>inspector tell me he'd approve electrical stuff that was clearly
>disallowed by the NEC. Same guy failed a professionally installed
>AC power circuit because the breaker didn't have the right sticker.
Can't hurt to talk to the B.I. if he / she is amenable.
>
>Find local solar installations and knock on the door to get
>real opinions.
We have A LOT of rooftop solar in this county and some ground mounted
systems. Most of the home owners have hired contractors to do
everything and don't know or understand much about what they have.
>
>Examine your payback spreadsheet to make sure you've included
>potential changes in what the 'grid' pays for electricity.
>If you're counting on any 'assistance' in the form of
>solar rebates or tax cuts or other incentives, make sure
>you understand whether they'll be there in a few years.
>
>I had a vendor try to lease me a solar system that had very
>attractive numbers based on available 'assistance'. Closer
>examination revealed that the future of the government
>assistance program was uncertain.
>You had to renew annually on one date.
>The available funds were limited
>and were gone within milliseconds of the opening bell.
>If you didn't get one, you were screwed.
Not counting on ANY incentives, if something materializes, it will be
a nice surprise. Not taking any loans or leasing anything, will
purchase everything out-right.
>
>Talk to your insurance company and decide how you're gonna
>keep people from stealing your panels...or vandalizing them.
Several big dogs and it is a rural setting, theft and vandalism is of
minimal concern and my HO insurance says I would be fully covered.
>
>I have no experience with grid tie.
>All I've done is MPPT controllers, battery management
>and sun tracking for small
>12V mountain-top radio repeaters.
>
>It's likely that the choice of the part that ties to the
>grid will dictate the rest of your system.
>15KW can be a lot of amps. Get whatever the panels produce
>converted to the highest voltage in the system as close
>to the array as possible.
>
>Leave enough space between panels so you can clean them
>and cut the weeds.
The area is already laid out, covered with landscape fabric and
several inches of P gravel. The few weeds which might grow can be
dealt with using glyphosate.
>
>START SLOW. Deciding that you made the wrong choice
>is painful AFTER you've got 48 panels.
I always do my homework which is why I am requesting references to
reading material.
Thanks.
>https://www.homedepot.com/p/Grape-Solar-100-Watt-Polycrystalline-Solar-Panel-for-RV-s-Boats-and-12-Volt-Systems-GS-Star-100W/204211365
>They are 36 cell panels good for 12V or 24V lead-acids with PWM
>controllers, I don't know how they would do as a high voltage series
>string with an MPPT controller. They handle partial tree trunk shading
>pretty well. If your array can be partially shaded there are
>distributed MPPT and inverter topologies that increase output, and
>initial investment.
>