Author Topic: Affordable DIY solar?  (Read 1899 times)

jo552006

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Affordable DIY solar?
« on: June 19, 2019, 09:11:57 AM »
I've been looking recently into installing a pv solar array on our property.  I'm thinking that with the government tax credit starting to be reduced after this year, putting money into reducing our electricity consumption (LED lights, efficient air conditioners, etc.) and installing a PV solar array would be a smart investment.

Here's where I'm stuck: Cost & Value

I plan to DIY everything except the electrical tie-in.  We have a net metering policy in Maine where I live.  I just can't seem to find information about various panels, quality, costs, whether used or surplus is a good idea, etc. 

Ultimately I'd like to get the best value I can on a 10KW or bigger solar array.  This would include Panels, optimizers, racking, grid tie inverter, any various other things I'm sure I'm leaving out.

If there's already a thread on this, could somebody point me in that direction?  If not, I can't be the only person who's decided that they want to install solar in a mustachian manner.

Dogastrophe

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Re: Affordable DIY solar?
« Reply #1 on: June 19, 2019, 09:55:32 AM »
Give Cabin Depot a look (https://www.thecabindepot.com/) - they have a US side to their website.  They are across the border from you in New Brunswick (Canada).  The owners are very good people.  They started getting interested in solar as an alternative to running a generator 24/7 to power their camp / cottage.  Their camp solar set up was DIY, which spun off into starting an off-grid business.  (disclaimer: I am biased as they have been friends for years).

Roots&Wings

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Re: Affordable DIY solar?
« Reply #2 on: June 19, 2019, 11:22:11 AM »
Wholesale Solar is another good place for a ready-to-install kit if you can DIY or find a local electrician to install. They were really helpful and can do a custom package too.

robartsd

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Re: Affordable DIY solar?
« Reply #3 on: June 19, 2019, 12:27:36 PM »
@Syonyk is currently building out a DIY solar system at his house in Idaho. I'm sure he'll eventually post details on his blog, but might be able to point you to good resources in the mean time. His blog documents the build out of the off grid system he uses for a shed that he uses as his office.

Cadman

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Re: Affordable DIY solar?
« Reply #4 on: June 19, 2019, 02:31:07 PM »
Renvu Solar is also a great resource with competitively priced parts.

I designed and installed our 10kW system 3+ years ago and it's performed flawlessly since going online. I've got details of the build here if you're interested: http://linearlook.com/solar/solar.html

Syonyk

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Re: Affordable DIY solar?
« Reply #5 on: June 19, 2019, 10:36:55 PM »
@Syonyk is currently building out a DIY solar system at his house in Idaho. I'm sure he'll eventually post details on his blog, but might be able to point you to good resources in the mean time. His blog documents the build out of the off grid system he uses for a shed that he uses as his office.

Syonyk is not building out a home solar DIY system.

Syonyk is currently giving up on beating his head against the code compliance plans review person in this state and attempting to get someone else to draw up plans.  Said company also beats their head against the code compliance plans review person, and we have some great ambiguity to resolve about what that person will consider a standby panel vs a backed up load, and if automatic breakers for load shedding make the house a standby panel, or if we have to physically reroute thermal loads to the outdoor panel (which will have to be expanded to fit these loads and which will be quite the expensive pain in the rear).

I honestly don't expect it to be done this year.  It's too late in the year and I've literally not even gotten the plans review completed, so I don't know what needs to be built.  I'm starting on the panel mounts, and should have the small one by my office done in the next few weeks, but it's a frustrating, pain-filled process that also means I haven't accomplished jack or shit on the rest of the property because I spent all my free time this spring going over the NEC with a fine toothed comb to find out what other section I was missing that would require me to redesign the whole damned thing, yet again.  For instance, me knowing that my home never pulls more than about 12-13kW doesn't matter, because per the NEC calculations, my home requires a 150A feeder.  This requires more passthrough capacity on the inverters, so I need another inverter chassis, which requires redoing other stuff.  BUT, all that depends on if the home is considered a normal feeder, or a subpanel, which depends on one guy's interpretation of that bit of the NEC.  And if I don't get this stuff done before the 2020 NEC goes into effect, it gets far, far worse.

So, no, I'm not "doing" DIY solar.  It's basically impossible for what I want, in this state, unless I want to spend a couple grand on plans review against a brick wall that comes back with "No, you've not considered everything, try again" as the extent of the response (because to give me more information would be "training," and they're a "code compliance organization," not a "training organization").

I'm too stupid to figure out home solar, is what it amounts to.

</rant>

I plan to DIY everything except the electrical tie-in.  We have a net metering policy in Maine where I live.

First question: Are you legally allowed to do that?  At least in my state, as a homeowner, I can do anything I want on my primary residence (subject to meeting code inspections, of course).  However, if an electrician so much as touches a wire, they have to then have the proper permit pulled for their work, and the parts need to be more or less separate - so we're looking at possibly having an electrician do the house AC side, up until it interfaces with the inverters in the shed, then I do the DC side - or something like that.  Details are still in the air, but "I do most of it, an electrician does the final hookup" is not easy, and they can't just jump in and do a small part of the project.  It's... a mess.

Are you going for roof mount or ground mount?  Be aware that under NEC 2017, you basically have to have per-panel electronics for a roof mount system to meet the increasingly silly rapid shutdown requirements, bought and paid for by Enphase, if I understand properly.

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I just can't seem to find information about various panels, quality, costs, whether used or surplus is a good idea, etc.

You'll need a UL listed panel, and beyond that... you can go down a rabbit hole of quality and price and degradation and warranty and on and on, all of which are basically formal guesses, or you can buy some low cost-per-watt panels from a halfway reputable company and assume they'll be fine.  Buy a spare or two, and you've covered most of the common cases.  The warranty only matters if the company is still in business, and it's a good bet that they won't be in most cases.  If you can haul them yourself from a local place, it should drive your costs down by a good bit.  I got two pallets of panels for less than $0.50/W locally, brand new (just "new old stock" - they're a year or two old, from a company that got bought out by someone else).

Used or surplus is probably a bad idea.  In addition to being randomly degraded, you'll probably get some odd questions from the code inspection people, and they're basically gods, in this context.  I don't think the hassle/risks are worth it for a large home system.

If you can find something like a ton of 72 cell panels coming off an insurance job at a big solar farm for $0.20-$0.30/W, that might be worth taking a gamble on and designing around.  Otherwise, shop around and find a friend with a pickup and trailer to go haul panels.

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Ultimately I'd like to get the best value I can on a 10KW or bigger solar array.  This would include Panels, optimizers, racking, grid tie inverter, any various other things I'm sure I'm leaving out.

If you do the work yourself, for a grid tie system (roof mount), you can probably manage $1.50/W installed.  Maybe a hair lower, but that's about as low as I can get system costs to for a pure grid tie system.  No battery, microinverters (to meet NEC 2017 shutdown requirements), Iron Ridge rails, and not a particularly long run to a panel that you can backfeed after derating the main breaker.  And nothing complex.  For a 10kW+ system, one might be able to edge that down to $1.25/W, but I don't think that's practically doable unless you have some screaming deals on panels and balance of system parts.

Ground mount is a bit different, and it depends on what you're doing.  My numbers are of no value to you because I want battery backup, and I'm going with ground mounts so I don't have the rapid shutdown requirements.  If I can come in under $3/W, I'll be pretty happy.  If I can actually build the stupid thing.

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If there's already a thread on this, could somebody point me in that direction?  If not, I can't be the only person who's decided that they want to install solar in a mustachian manner.

There's Pete's post, where he demonstrates that he lives in a jurisdiction that doesn't care what you do.  If you live in one of those places, slap your name on some sample diagrams, submit it, and have a ball. 

https://github.com/Syonyk/HomeSolar/tree/master/OneLine is my current progress, which everyone tells me is "close," but the guy who approves it doesn't think so, and mostly won't tell me why not.  And his opinion is literally the only one that matters.  I've not updated it to three inverters and added the subpanel calculations, but that bypass on the house side is part of the complexity that is throwing a wrench in the works.  I want to be able to bypass the whole system if needed for maintenance, and it ends up throwing a ton of wrenches into the works.  I also end up with giant panel busbars to handle the amps, because the calculations don't consider the Radian inverters and how they work, and it's cheaper to do the nonsense math and throw a bigger panel in than to pay someone to do the calculations on fault currents and such to prove that a smaller panel will be just fine.

From what I understand from a friend in Maine, though, you're going to have a seriously uphill battle as well.

robartsd

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Re: Affordable DIY solar?
« Reply #6 on: June 20, 2019, 09:25:58 AM »
I'm starting on the panel mounts, ...
I think I saw one of your comments about this and thought that you might have finally conquered the code review step. Sounds to me like you have a lazy bureaucrat as the gatekeeper here. Good luck.

Syonyk

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Re: Affordable DIY solar?
« Reply #7 on: June 20, 2019, 09:30:38 AM »
Nope.  Sill nothing approved.

I don't think he's lazy, I think he's just solely focused on enforcing the NEC, as he interprets it (for as long as it is, there's a ton of ambiguity in it), and is heavily overloaded.  If it's something weird, it's just not getting approved until you communicate to him that it's correct, by his standards.  And I don't think it's feasible for a homeowner to do that for anything complex.

Oh, and these reviews of my stuff are racking up $65/hr.  Apparently 20-50 hours is commonly charged for this sort of stuff.

 

Wow, a phone plan for fifteen bucks!