Residential solar people?

[larboc]

So just curious of yall who have gone through inspections and the like. I can't find anything in local code that would require me to do any type of plan review or inspection for a non-grid tie system. I was looking at hybrid inverter, so the only connection to mains is a draw only connection.

Due to the terrible buyback rate here all the calculators are showing a 20 year payback of -$8000. But I have a ton of free batteries and would like the redundancy for a few key systems.

Going to be dictated by your AHJ. In my case I needed 2 things.
1) Net metering agreement from the utility. I made a simple one-line diagram in Visio and send that off with the permit and $100 fee and got approved. They have the net meter in hand and are waiting for a completed electrical permit/inspection from the county to put it in.

2) I then had to get an electrical permit and inspection, but the form I filled out for the permit didn't really have anything on it specific to regenerative systems. The boxes I checked are related to a 40 amp appliance getting hooked into a 200 amp residential service. I don't know if the local inspector will even look at the DC side of things, and likely has no clue about any RSD rules. Permit was around $100.

I'm not sure what you're setting up with a hybrid inverter that you wouldn't want to be grid tied, but it seems like if you're going to be installing panels to charge batteries you would want to put power back into your grid once the batteries are full or you're underutilizing the power you're generating. In your case where you don't get much credit for power generated back to the grid, you would have the inverter setup to reduce purchased energy from the utility. It would first pull power from the panels, then power from the battery's when you're using a lot of power. Then when it's sunny but you're not using much power it would use extra power to charge batteries first, and export once they are full. That kind of operation mode is common and would be pretty easy to implement. What kind of system did you use to calculate payback?

 

[bigun]

So just curious of yall who have gone through inspections and the like. I can't find anything in local code that would require me to do any type of plan review or inspection for a non-grid tie system. I was looking at hybrid inverter, so the only connection to mains is a draw only connection.

Due to the terrible buyback rate here all the calculators are showing a 20 year payback of -$8000. But I have a ton of free batteries and would like the redundancy for a few key systems.

Where are you at?

 

[kf4zht]

Where are you at?

Calhoun, GA

I want the backup power that batteries give is a big reason. I'm targeting a few key items, get the power bill lower and have a reserve. I have 2 generators for longer outages

2 Fish tanks (1 salt, 1 fresh)
Freezer (soon to be 2)
Fridge
Network crap

Ran a killawatt on all of it. Averaged 2000-2500 watts per day. Lined up with the typical use I was seeing running it on the generator

I have ~250a of batteries @24v from work. So ~2.5 days capacity.

Figured I would put up 4-6 panels of 250-300w each. That will be about 60% of my high sun roof space. A couple of the solar hour charts put me at 4.5-5 hours per day. We do get a good bit of rain. On a good day that should be ~8000-8500 watts total. Enough to run for the day and fully charge the bank.

After I see how the real performance is I can start adding more things to it. The lighting is all LED so that would be an easy move, my workstation, etc. It also lets me get rid of 2 UPS units

 

[larboc]

If you're subject to NEC 2017 you should consider microinverters with that small of a PV system and an AC coupled battery bank system. Do some reading on emphase stuff.

 

[kf4zht]

If you're subject to NEC 2017 you should consider microinverters with that small of a PV system and an AC coupled battery bank system. Do some reading on emphase stuff.

I'll do some looking. We are on NEC 2014 per the permit office website

 

[WTF?]

If you're subject to NEC 2017 you should consider microinverters with that small of a PV system and an AC coupled battery bank system. Do some reading on emphase stuff.

I'll do some looking. We are on NEC 2014 per the permit office website

Just found this micro inverter vs traditional comparison:

Enphase Micro-Inverter Review - MC Electrical | We Know Solar

Enphase microinverters are reliable, but are they the best shade solution? This review analyses the pros and cons of Enphase for solar panels, including shade performance, voltage rise, and monitoring issues.

www.mcelectrical.com.au

I wish I had been able to find actual data like this ~18 mos ago when I was comparing the two hardware options Between two companies trying to undercut each other and couldn’t find stats to support the sales reps claims from anyone other than the equipment manufacturers sales material.

( I ended up with a solar edge with panel optimizer installation since that solar company made a price concession for COVID shutdowns that I couldn’t pass up and I was able to size the inverter for future expansion without having to change the inverter which I saw as a bonus.)

 

[MChat]

Just saw this thread and reading through it I realize how little I know about this subject. I know just enough about home wiring to be dangerous; everyone in this thread may as well be speaking a new language.

My wife and I recently purchased some off-grid land in North-Eastern AZ that we are planning on ultimately making our retirement/semi-retirement home. Being in AZ I am thinking that solar is enough, however I have seen locals also have wind generators as well so we are also considering a hybrid wind/solar setup. And since it is off-grid, a generator backup is also desired.


What are some good resources online to read and get up to speed?

Is it better to piece together a system, or buy a "package"?

 

[WTF?]

Just saw this thread and reading through it I realize how little I know about this subject. I know just enough about home wiring to be dangerous; everyone in this thread may as well be speaking a new language.

My wife and I recently purchased some off-grid land in North-Eastern AZ that we are planning on ultimately making our retirement/semi-retirement home. Being in AZ I am thinking that solar is enough, however I have seen locals also have wind generators as well so we are also considering a hybrid wind/solar setup. And since it is off-grid, a generator backup is also desired.


What are some good resources online to read and get up to speed?

Is it better to piece together a system, or buy a "package"?

These guys had a pretty solid knowledge base of resources and a sales/ support step willing to walk a novice through install.

Alternative Energy Resources

Explore our comprehensive learning resources on residential wind turbines and solar panels. Get started with renewable energy projects, installation guides, and troubleshooting tips.

windandsolar.com

If COVID hadn’t presented the opport to have my system installed for cost of materials, I would have bought through them; they set up a custom system/ quote for me to compare their equipment prices vs the pro install proposals with The exact hardware so it was apples to apples.

 

[tsm1mt]

From what I'm reading, all string inverters have similar noise they put off but some people (worn out ears) can't hear it. tsm1mt do you notice the SMA's you have making a high pitched noise when standing next to them?

I don't hear a whine line you describe - I hear the cooling fans going.

I didn't know what it was at first - WTF is that noise over there? - but when inverter output goes up there's a little exhaust fan that starts going.

The inverter nearest the back door of the house is most noticable, because it's in the backyard.

The two inverters on the new shop I hear only when I walk into the shop - nothing once I'm inside (the transformer for the radiant heat makes more noise)

And to recap again - I picked the string inverters specifically to avoid RF noise that would trash the HF bands for me.. and I haven't noticed any new birdies, hash, or other interference since I installed the panels - and the 80m/160m dipoles darn near go over the panels, and the higher band beam is pretty much "right there" too.

 

[larboc]

Figured I'd update.
The high pitched noise is the same for the SMA's and ABB's finally got online at work so I'm thinking it's just natural of the beast.
Anyway, I FINALLY have enough of what I ordered to get started. Had a few panels and some rail get damaged in shipping and it was a mess.
I now have the main area racking just about done. Now I have to get a junction box setup for the penetration through the roof, level the rails, and start hanging panels.
Now I'm looking for a way to seal water from getting between the panels during snow melt.

 

[larboc]

Pretty much finished. All the panels mounted, all the fire raptors mounted and wired. I bought the quickmount q-boxes and have them under the panels, then they go into the attic into a 4-11/16" box where they transition to 1" EMT staying at least 12" away from the roof deck. The q-boxes only have 3/4" EMT coming out the back through the roof and are too small to allow a PV wire to bend inside of the so I used polaris connectors to change to #10 THHN in the boxes, I had hoped to use PV wire the whole way but it wasn't going to work out. Each q-box pass through has 4 dc conductors, a solid #6 ground, and tray cable to power the fire raptors, too much cable for 3/4". Bottom panels are in string 1, top panels in string 2. 12 panels per string so the inverter is safe down to -60F or something silly.

Wire management was more complicated than I anticipated. I used twice as many clips as I estimated but no wires touching the roof or back sheet. Also, since the q-boxes are under the end panels, no visible cabling or conduit or any wires exposed to continuous direct sunlight.

I filled the short edge gap between panels with Loctite PL rubber roof sealant to keep water from getting under and building ice castles, we'll see how it works. Rain JUST hits the gutters as it comes off the panels, snow should easily clear.

Only hold up now is labels. I put off ordering labels because it's so confusing. I ended up ordering a "kit" of labels off of ebay that's I later noticed aren't reflective which is okay for nec 2020 I think, but not 2017. We'll see what the inspector says. The NEC labeling requirements are ridiculous. I think I need:
1) Labels marking the back feed breakers in the sub-panel and main panel
2) Labels every few feet on EMT and each j-box warning of PV current.
3) Rapid shutdown yellow label
4) Diagram of the electrical system (I'm going to print it off and put it in a lexan sign holder and see what he says.


I also don't have an outdoor disconnect which as I understand it isn't necessary since I've got rapid shutdown, but we'll see what he says on that too. May have to pay for a second trip.

The utility won't put in my net meter until I have a signed electrical inspection or I would probably forgo, some of this.

Looking back I would have tried harder to find a spot on my yard to put this, living space roof mounting is a PITA.

 

[Provience]

Well it looks good anyways.

Sucks about the labeling, seems strange to require it for residential stuff

 

[arse_sidewards]

Looking back I would have tried harder to find a spot on my yard to put this, living space roof mounting is a PITA.

You think it's a PITA now. Just wait a month until you have a snow/ice dam between the ridge of your roof and the beginning of your panels.

 

[larboc]

Passed my inspection yesterday! Inspector didn't look at 99% of all the work I did to make it NEC 2017 compliant.

 

[larboc]

Following up in case anyone cares....
Snow was off the panels for about 1/3 of march and 75% of april. It was a snowy, cloudy, april. April generation was 638kWh from the inverter which is a little lower than the models predict for average weather years but given the snowier and cloudier than average april it makes sense. It still exceeded my purchased power by ~2x so I'm at a net +300kwh for April so my bills should be $25/month for the next 25 years, hopefully.

 

[CarterKraft]

Following up in case anyone cares....
Snow was off the panels for about 1/3 of march and 75% of april. It was a snowy, cloudy, april. April generation was 638kWh from the inverter which is a little lower than the models predict for average weather years but given the snowier and cloudier than average april it makes sense. It still exceeded my purchased power by ~2x so I'm at a net +300kwh for April so my bills should be $25/month for the next 25 years, hopefully.

Can you recap kw of array and your average monthly usage?
This is on my mind all the time.

 

[larboc]

Can you recap kw of array and your average monthly usage?
This is on my mind all the time.

7.8kw of panels in two strings. Abb string inverter.
Monthly usage between 250kw and 600kw. Electric dryer and range. Wood heat. Electric heat pump water heater with preheating from wood stove.

 

[brantb]

Just did a quick search to see if solar systems have jumped way up in price but it seems like wholesalesolar or whatever they are called now dont list prices. Seems their inventory is also way low for what they list on their site.

Last time i looked it was ~10k before rebates for a system around 3.7kwh but that was a couple years ago. Anyone know what prices are like now or even if you can get systems/components?

 

[ThePanzerFuhrer]

7.8kw of panels in two strings. Abb string inverter.
Monthly usage between 250kw and 600kw. Electric dryer and range. Wood heat. Electric heat pump water heater with preheating from wood stove.

Can you post your monthly production averages for the months you had it running? I am thinking about putting up a large set but want some real world data from a person near me. My power bill is between 600-1000 a month and want to knock that down.

The 600 is during the summer months and 1000 during the winter. Repair season is hard on the power bill.

 

[[486]]

Can you post your monthly production averages for the months you had it running? I am thinking about putting up a large set but want some real world data from a person near me. My power bill is between 600-1000 a month and want to knock that down.

The 600 is during the summer months and 1000 during the winter. Repair season is hard on the power bill.

call your power company, see what they do for metering
mine does 1:1 metering for up to a 40kw array (they charge 12 cents, and pay out 12 cents per kw/h)
and they'll cut a check for any overages, not just apply a nonrefundable credit to the account

down in the cities at my mom's place, they charge 13 cents and pay 3 cents, so it makes absolutely no sense to set up any panels

 

[Yota Up]

What is the current expectation of money put in vs. money saved over what period of time that makes solar a good idea?
Is the price cut for buying used off craigslist worth it for older stuff or is the new and current more important?

 

[larboc]

Just did a quick search to see if solar systems have jumped way up in price but it seems like wholesalesolar or whatever they are called now dont list prices. Seems their inventory is also way low for what they list on their site.

Last time i looked it was ~10k before rebates for a system around 3.7kwh but that was a couple years ago. Anyone know what prices are like now or even if you can get systems/components?

Prices are around 10% higher now across the board than when I bought. I had to order some iron ridge racking parts for work and they are looking like delivery will be at least 2 months after I ordered.
Shop around, I was able to find components in stock at some more 'fringe' suppliers that were backordered for months at CED.

 

[Etyler2]

Just did a quick search to see if solar systems have jumped way up in price but it seems like wholesalesolar or whatever they are called now dont list prices. Seems their inventory is also way low for what they list on their site.

I can post what Sunpower is charging me if you’re interested.

Last time i looked it was ~10k before rebates for a system around 3.7kwh but that was a couple years ago. Anyone know what prices are like now or even if you can get systems/components?

 

[larboc]

Can you post your monthly production averages for the months you had it running? I am thinking about putting up a large set but want some real world data from a person near me. My power bill is between 600-1000 a month and want to knock that down.

The 600 is during the summer months and 1000 during the winter. Repair season is hard on the power bill.

Only about 200kwh from when I got the inspection in november through end of february, it snowed and stayed below freezing from the second week of november till late march. Never got a warm up to slide. I had planned on not having any generation for december-february in my ROI study, no huge surprise.

You get a lot less snow, and get almost double the solar radiation in the winter months down there than me so anything you do will do better than I can in winter. I get a little more sunlight in the summer than you do so that helps make up for some of it. Overall I get about 10% less solar radiation than you do over the course of a year, but because of the snow cover the usable power is much less/zero in the winter. Less snow also means less $$ on racking.
PVwatts is a good place to start, sma's simulation is good if you want to model it more accurately, NREL's SAM is the best.
I will update with monthly data for my site, but you're going to be more accurate if you model it yourself based on wauaus data.

As mentioned, you need to know what your utility will offer in terms of generation. 1:1 net like I have is the best, but depending on your load profile it's isn't critical to a short ROI for a smaller system. I'm guessing most of your electrical demand is during daylight hours anyway.

 

[brantb]

Etyler2 post it up if you dont mind.

At my old house(2016) i had someone do the install and it was 17k before the 30% tax rebate for a 3.7kWh system. A few years later i looked at a very similar system and it was 10k for parts(2019ish). We will be selling the house we are in next year and moving, so no reason to install it on this one, but with rates rising i am thinking about the next house. At this point i wouldnt mind buying the stuff now if prices are going to continue to jump. I could even store it on my dads garage roof for a year or two and give him free electricity.

 

[AKnate]

Pretty much finished. All the panels mounted, all the fire raptors mounted and wired. I bought the quickmount q-boxes and have them under the panels, then they go into the attic into a 4-11/16" box where they transition to 1" EMT staying at least 12" away from the roof deck. The q-boxes only have 3/4" EMT coming out the back through the roof and are too small to allow a PV wire to bend inside of the so I used polaris connectors to change to #10 THHN in the boxes, I had hoped to use PV wire the whole way but it wasn't going to work out. Each q-box pass through has 4 dc conductors, a solid #6 ground, and tray cable to power the fire raptors, too much cable for 3/4". Bottom panels are in string 1, top panels in string 2. 12 panels per string so the inverter is safe down to -60F or something silly.

Wire management was more complicated than I anticipated. I used twice as many clips as I estimated but no wires touching the roof or back sheet. Also, since the q-boxes are under the end panels, no visible cabling or conduit or any wires exposed to continuous direct sunlight.

I filled the short edge gap between panels with Loctite PL rubber roof sealant to keep water from getting under and building ice castles, we'll see how it works. Rain JUST hits the gutters as it comes off the panels, snow should easily clear.

Only hold up now is labels. I put off ordering labels because it's so confusing. I ended up ordering a "kit" of labels off of ebay that's I later noticed aren't reflective which is okay for nec 2020 I think, but not 2017. We'll see what the inspector says. The NEC labeling requirements are ridiculous. I think I need:
1) Labels marking the back feed breakers in the sub-panel and main panel
2) Labels every few feet on EMT and each j-box warning of PV current.
3) Rapid shutdown yellow label
4) Diagram of the electrical system (I'm going to print it off and put it in a lexan sign holder and see what he says.


I also don't have an outdoor disconnect which as I understand it isn't necessary since I've got rapid shutdown, but we'll see what he says on that too. May have to pay for a second trip.

The utility won't put in my net meter until I have a signed electrical inspection or I would probably forgo, some of this.

Looking back I would have tried harder to find a spot on my yard to put this, living space roof mounting is a PITA.

I've never heard of anyone sealing between the panels.

 

[AKnate]

What is the current expectation of money put in vs. money saved over what period of time that makes solar a good idea?
Is the price cut for buying used off craigslist worth it for older stuff or is the new and current more important?

It depends on location.

I've had my panels since 2013 and they've made 24.7 MWh. That's about $5000 of power. I paid about $10k for the setup.

 

[larboc]

I've never heard of anyone sealing between the panels.

...till now!
There is actually a company out there that sells a strip for doing it, mainly for carports. I had no issues with ice between panels throughout the winter so I'm glad I did it. I manage a decent sized solar research installation and have seen some serious ice under horizontal panel gaps when the conditions are right on open racking. No harm on open racking to get 2 foot icicles, but no bueno on a roof.

 

[larboc]

What is the current expectation of money put in vs. money saved over what period of time that makes solar a good idea?
Is the price cut for buying used off craigslist worth it for older stuff or is the new and current more important?

I'm on track for a 4-5 year payback on my 7.8kW system. I spent around $1/watt on mine in parts and didn't factor in my labor. Your utility agreement makes a huge difference on payback.

No way I'd buy used panels unless they were really cheap and I had the EL images and PV curves for each of them. Too easy to cause damage in handling, microcracks can't be seen without EL imaging, hidden damage that will lead to PID, etc. New panels gave gotten so powerful and cheap and are only 1/2 the cost of the total equipment purchase, plus they typically have 25 year warranties. You can still get new panels for under 50 cents a watt.

 

[AKnate]

I'm on track for a 4-5 year payback on my 7.8kW system. I spent around $1/watt on mine in parts and didn't factor in my labor. Your utility agreement makes a huge difference on payback.

When I set mine up, the Po Co would run a KwHr credit for 12 months and then pay it. They soon changed it to paying it every month, which is way less of a good deal. Buy it at 0.05 Kw/Hr and I pay just under 0.20 KwHr