I'm interested in understanding the key factors involved in planning an off-grid solar PV system for a home.

One of the most important considerations seems to be estimating daily electricity consumption before deciding on the solar array size. Roof space, local sunlight conditions, panel orientation, shading, and seasonal changes can also affect the system's performance.

I'm also curious about how installers estimate the appropriate solar array capacity for different household loads and how they account for cloudy days and seasonal variations when designing an off-grid system.

For those with experience in residential solar PV installations, what factors do you consider most important when planning an off-grid system, particularly in regions with hot summers and variable sunlight?

I'd appreciate practical insights and lessons learned from real installations.

Hi all, I’m setting up the electrical shading partitions in PVsyst (v8) for a single-axis tracker project and want to sanity check my approach.

Setup:

• N-S horizontal single-axis trackers with backtracking
• Half-cut modules in portrait, [1P / 2P] per tracker
• String inverters
• Each tracker table is exactly one 23-module string

What I understand from the PVsyst docs:

• For regular arrays, modules on the same MPPT input should see the same partial shading, so I shouldn’t split along the tube.
• For half-cut modules in portrait, the docs say to use partitions at half the module height (the “xT” case, 2x partitions across the table).

What I currently have in the 3D field editor:

• Nb. rectangles in length (Y): 1
• Nb. rectangles in width (X): 2

My questions:

1. For a table that is a single 23-module string, is 1 partition along the tube and 2 across the table (one per half of the half-cut module) the right call?
2. Should I split along the tube at all, or only if shading varies along the row (hilly terrain, end shading from obstacles)?

Was hoping to have someone take a look at this and let me know I have not lost my mind--

thanks in advance

I am using all Top Rack TRT02 components. I am using 3 rows of 4 panels each, for a total of 12 solar panels. Each row will have the panels mounted in landscape. Each row will have 2 rails of trto2 rails.  Hidden end clamps and mid clamps will secure each row of panels.  Each rail row will be composed of 3 sections of rail connected by rail splices. According to the manual, these are designed to bond the entire structure together.

Based on the information from the manual, when it is all said and done, the entire 12-panel structure will be bonded.

To ground the system I am proposing to install grounding lugs on each end of the rails ( for a total of 12); in addition, there will be grounding lugs attached to each panel. There will be space between each row, about three inches so I can attach the lugs. There will be a properly sized copper wire that will connect all 24 grounding lugs. This grounding wire will then ( in a continuous run) be connected to a ground wire that will run to the house and be attached to the home's electrical grounding system

A young lady who works for me and her partner just bought a small piece of land. Utility power is 1/2 mile away and at this point it is not economically feasible for them to connect. Obviously they did not do their due diligence but here we are. When she brought the issue to my attention the thought of off grid came to mind. I'm thinking a smaller house with propane for heating and cooking with an off grid battery solar system. Before I bring this up to them I thought I would throw it out here for opinions. Money is an object so it needs to be as economical as possible. What are their options and what kind of entry level cost might they be looking at?

Im trying to save and stretch every dollar and invest my money into things I see worth while . Im considering buying a pecron 3600 with the thought of an insurance policy in times of blackouts and possibly running a ac with an expansion pack . Is this investment worth while or is pecron 3600 to small to see any benefit 🤔

My SolarEdge system worked fine for about a year with no cable connected. It was communicating wirelessly, either through a cellular connection or something similar. Then it randomly stopped, and the mySolarEdge app now says "site not communicating."
I went out and installed an ethernet cable from the inverter to my Xfinity gateway to try to fix it, but nothing changed.
Here's what I know:
The inverter shows as connected by ethernet in my Xfinity gateway.
I restarted both the inverter and the gateway.
The inverter has one solid green light and no screen.
My installer went bankrupt, so I have no installer account, and SolarEdge Go only lets installers log in.
How would you fix this? I'm open to any ideas, whether it's router settings, something on the SolarEdge website, or a trick for resetting the inverter's connection without the installer app. If you've been through this exact situation, I'd love to hear what worked.
Thanks!

Not sure this is the correct sub, if not if you could recommend me one.

I have a friend moving into a house in the metro west region in MA. New roof.

Trying to help, he is from out of state, he mentioned lots of scams etc he had to weed out in the past in another state. Wants to this very soon as I guess panel prices going up in 2 months?

He is looking to buy. Looking for a good place to buy/install etc.

I bought my residential solar system in South Carolina back in 2017 and purchased a 20-year Extended Service Agreement through SunSystem Technology (SST Home). Since then, the servicing company has been bought and rebranded multiple times, going from SST to NovaSource Power Services, and now to Otovo.

Every time I have needed support over the last 9 years, it has been a massive headache, but this current issue has hit a brick wall:

- The Hardware Issue: I have two panels down, and my SolarEdge inverter is throwing a 2 Module voltage mismatch error on Panel 1.0.23. I work in IT, so I have already verified that my inverter is hardwired to my network and communicating properly. This is a physical hardware failure on the roof (likely a degraded panel).

- The AI Support Loop: When I first reached out, support claimed they "don't service South Carolina," even though my SC address is literally at the top of the signed 2017 contract. When I submitted a ticket through Otovo's portal, I got trapped talking to an automated bot (us-support@otovo.ai) that kept claiming it couldn't find my legacy installation records in their database, even after I attached the signed PDF contract, my legacy Account ID, and the inverter serial number.

- Executive Ghosting & Invalid Billing: I escalated the email chain to multiple NovaSource/Otovo VPs, Directors of Operations, and eventually the CEO. Nobody replied to my emails. Randomly, a technician was finally dispatched to my house. He confirmed my exact diagnosis (bad panels that need to be replaced) and left without fixing anything. Immediately afterward, they tried to bill me a $299 service fee. My contract explicitly states that initial service labor is waived and subsequent service visits are capped at $75, plus a Director of Operations previously assured me my account wouldn't be charged service fees after a past multi-month outage.

Right now, leadership is completely ghosting my emails, they haven't confirmed if the replacement panels (RMA) have been ordered, and they are trying to stick me with an invalid $299 charge.

My questions for the community:

1) Has anyone else with a legacy SunSystem Technology or NovaSource warranty actually gotten Otovo to honor their contract recently?

2) Does anyone have a working direct phone number or a human contact at Otovo/NovaSource who handles legacy ESP contracts and RMAs? (The 833-317-6937 number just routes back into their black hole).

3) If Otovo continues to ghost me on the panel replacement, can I have a local independent SolarEdge installer process the hardware RMA directly with the panel/optimizer manufacturer, or will that cause issues?

Any advice or insider contacts would be hugely appreciated!

Hey everyone,

Senior renewable energy engineering student here, final year project due in a couple months, and I still haven't locked in an idea. Starting to panic a little.

Topics I'm circling for now:

• Perovskite solar cells
• Thermophotovoltaics (TPV)
• Passive radiative cooling
• Black body radiation / solar spectrum tailoring
• Nuclear photovoltaics.

I can pick one or combine two. Need just which has the potential to somehow improve efficiency other than what's already in the literature.

If you're in TPV, nuclear engineering, PV research, radiative cooling, or anything adjacent. I'd really appreciate your other ideas. What combos have legs? What's oversaturated? What would actually be fun and meaningful to work on? What am I missing?

Thank you! I'm genuinely excited but paralyzed by the options.

Good evening everyone,

My wife and I own a small farm in northeast PA and we’re looking at putting in a ground mount system to power our residence and our outbuildings throughout the property. We’ve had solar before mounted on our roof on our previous home so we are not new to the benefit benefits of solar. I recently got an estimate for a fairly large system, but the price seems shockingly high. It is a 37 kW system. It consists of 68 panels. Including installation and #Warranty the company is estimating it at 98,000. We would qualify for the commercial tax credit and the 10% community credit so after all of the credits and incentives, it would come down to roughly 60,000. Does it seem high?

I work as a solar technician, and when I look at a custom van I check the power system before the cabinetry. Here is the short version of what the price difference really buys.

**Budget build (roughly 100Ah battery, PWM controller, small inverter):**

- Fine for weekends, lights, phone, a small fridge

- Mixed brands that don't talk to each other, basic fusing

**Professional build (what you see in the $150K range):**

- 400-800Ah LiFePO4 at 12V (or 24/48V)

- 400-800W of solar

- 3000W pure sine inverter/charger (Victron MultiPlus-II is common)

- DC-DC or secondary alternator charging, plus shore power

- Proper fusing on every positive run, tinned marine-grade wire, a monitoring system that ties it all together

**Where the money really goes:** not the batteries alone, but the engineering. Correct wire gauge, short runs to limit voltage drop, thermal protection, and fusing that survives years of road vibration. Rubbed-through insulation is a real fire risk.

**Is it worth it?**

- Yes if you live full-time in extreme weather, run AC from batteries, work remotely with heavy loads, or spend weeks off-grid.

- No if you camp on weekends with hookups. A portable power station and a simple stove cover that for far less.

Happy to answer questions on sizing, wiring or battery choice. What is your current setup, and what do you wish you had done differently?

Hi all!

Hoping to get some feedback about purchasing a house with existing solar panels.

Overview:

- older house that has been renovated 1915.

- Current owners purchased in 2022

- Solar system installed in 2022

- Financed

- Loan would be transferred to buyer I think. 1.99% interest, ~$100/month.

Questions I'm asking seller/things I'm checking:

- previous electric bills to compare savings

- age of roof in relation to panel installation

- Is the solar cost added to the cost of the house? (clarifying)

- Inspect the roof below the panels for any water damage

- what net metering they are a part of with their utility company or do they have batteries? Is there a battery backup?

- what net metering they are a part of with their utility company or do they have batteries? Is there a battery backup?

- Are the warranties transferable?

- copies of the original municipal building permits and utility interconnection/net metering agreements?

- Ask for the building/electrical plans for the system, who the current services is if there are issues and if the roof was replaced when the panels were installed.

- make sure the inspector I choose knows about solar or get separate solar inspection.

*Some additional info I got:

Contractor: Ion Solar

Improvements: Solar

System Size (kw): 4.94

Number of Panels: 13

Panel Manufacturer: Silfab

Inverter Manufacturer: Enphase Energy

Am I missing anything? Thanks in advance?

Ambrosia Energy, founded by the duo who sold satellite startup Swarm to SpaceX, has started work on a 10 GWh battery factory near Austin. The plan is solar plants that power a data center by day and charge batteries for the night, with a first West Texas project pairing 300 MW of panels with 660 MWh of storage for 30 MW of continuous power.

The catch is scale and proof: the $100 per megawatt-hour price, 99.3% uptime target, and output goals are the company’s own claims, and its pilot so far is only 200 kW running for 100+ days.

I got some info from a non-profit, some folks who read contracts etc. Here is the reply:

I also talked to my Tax/CPA guy. Digging in to the particulars with him, it's a early loan payoff and the loan is payed off right away the up front money is all you pay. There is NO settlement at the 5 year point, the system is signed over to the owner. Of course some weird stuff could happen. The wording in the contract has to be spelt that way to get past the IRS. Which creates uncertainty for the buyer. If you do a regular loan instead of an immediate payoff, then the Fair Market Value comes into play at the 5,6, or 10 year mark.

_________________________________________

Energy Independent Solutions has good online reviews, 5.0 on EnergySage and 4.65 on Solar Reviews. They have a 94/100 on Wattbott. Here is their Better Business Bureau profile.

The proposals include four options:
Option 1 – Propel Pre-paid Lease
Your system size on this is 9.66 kW. The standard system price is $31,753.88. The proposal estimates 10,717 kWh of annual production and 108% consumption offset.

Option 2 – Propel Pre-paid Lease with Enphase Battery
Your system size is 9.66 kW with 10.0 kWh of battery storage. The standard system price is $31,753.88, plus $16,500 for the installed Enphase 10C battery, for a total system price of $48,253.88 before the listed Indirect ITC Benefit. The proposal estimates 10,717 kWh of annual production and 108% consumption offset.

Option 3 – Tesla Cash/Financing
Your system size is 9.24 kW. The cash price for the system is $24,979, or approximately $2.70 per watt. The proposal estimates 10,061 kWh of annual production and 101% consumption offset. The proposal also offers financing at 9.49% for 15 years, with a monthly payment of $262.75, or 6.99% for 25 years, with a monthly payment of $213.73.

Option 4 – Tesla Cash/Financing with Battery
Your system size is 9.24 kW with 13.5 kWh of battery storage. The cash price for the system is $40,479. The proposal also offers financing at 6.99% for 25 years, with a total loan amount of $48,764 and a monthly payment of $346.35. The proposal estimates 10,061 kWh of annual production and 101% consumption offset.

Your utility bill shows approximately 10,042 kWh of usage over the past 12 months, so the proposed production is reasonably close to your actual usage.

Standard average solar pricing from what we've seen in Pennsylvania is about $2.60 per watt before incentives. The Tesla cash option is approximately $2.70 per watt, which is close to the current Pennsylvania average.
Source: https://www.energysage.com/local-data/solar-panel-cost/pa/

The warranties listed in the proposal are:

• Propel Options 1 & 2: 25 years for the panels and 25 years for the inverters; the Enphase battery in Option 2 has a 15-year warranty.
• Tesla Option 3: 25 years for the panels, 30 years for panel performance, and 12 years for the inverter.
• Tesla Option 4: 25 years for the panels, 30 years for panel performance, 12 years for the inverter, and 10 years for the Tesla Powerwall 3.

EIS Solar lists a 10-year workmanship warranty, but I recommend confirming the warranties for craftsmanship, roof penetrations and labor.

Regarding the Propel options:
As we discussed on the phone, the Propel options use a different ownership structure than a conventional cash purchase or solar loan. The main item that was a bit vague (and the larger difference) is the purchase option following Contract Year 5.

Under the Propel agreement, the purchase price at that time is based on the fair market value of the system, with the agreement also providing for other factors to be considered, including the system's age, location, size, equipment type, service costs, value of electricity in the area, etc. This can be very subjective.

Because the actual purchase price at year 5 cannot be determined from the proposal today, we recommend asking the installer/Propel how they expect the Year 5 buyout to be calculated and whether the purchase terms or a specific buyout amount can be established or clarified in writing before signing. You may also want to ask whether any of these terms can be changed before signing and, if so, request the revised terms in the final agreement.

The proposal itself appears to be reasonably sized for your historical utility usage. The Propel options are priced differently from the Tesla cash option because of the different ownership and financing structure, so we recommend comparing the total amount you will pay under each option, as well as the Year 5 purchase terms, rather than comparing only the system prices shown in the proposals.

Here’s our article on how to read your solar proposal:
https://www.solarunitedneighbors.org/go-solar/how-to-read-your-solar-proposal/

You can also check out these helpful resources:

• Download our battery storage guide: https://act.solarunitedneighbors.org/a/battery-storage-guide
• Net metering overview: https://solarunitedneighbors.org/resources/net-metering-what-you-need-to-know/
• Download our Go Solar Guide: https://act.solarunitedneighbors.org/a/go-solar-guide
• If you'd like to calculate how much battery storage you will need to meet your energy goals, visit the PV Batt website.

Hope this helps, and please let me know if you have more questions or would like more information. If you'd like to join our co-op, click here to explore one in your area or join a waitlist for upcoming co-ops. Joining a co-op isn't a commitment to going solar, but it means that you'll get a custom proposal from the group's chosen solar installer.

Please let me know if you have any questions about the information I’ve shared.

Question: Under IRS Notice 2026-15, is a signed certification from a PV module manufacturer identifying the PFE/non-PFE status of solar cells and other module components sufficient when using IRS-assigned cost percentages?

Answer: Potentially yes. A manufacturer's certification may satisfy the IRS Certification Safe Harbor if the manufacturer is the taxpayer's direct supplier and the certification meets Section 4.03 requirements, including supplier identification and signature under penalties of perjury. Separate certifications from every component manufacturer and individual module serial-number tracking are not expressly required.

*IRS Reference: Notice 2026-15, Section 4.03 – Certification Safe Harbor

I am in California on NEM3 with a solar array and a 15kwh battery. My installer has set it up so that I'm on "self-consumption" but the battery will not export to the grid.

Is this the correct set up? At this time of year, the battery probably discharges 70% to the house overnight, which makes me think there's money left on the table. They say exporting to the grid will degrade the battery due to additional cycles but it's already cycling daily?

What happened was we are thinking to get ourselves a sun room, and then we figured BIPV might not be a bad idea, considering the extra power we get, in addition to a sun room ( while the light gets in and the transprency is conpromised of course, to get the free power)

Being Chinese and specialized in sourcing, we reached to quite many manufacturers in China ourselves and tried to benchmark different companies' products, strength, downside, price, and etc..

As we learnt more and more, we started to think maybe should make it into a business ourselves. Given the wide use of BIPV in architecture design, roof and side walls, public art installation or landscape installation, resort villa and etc. More of best combination of visual arts (maybe :p) or at least leisure experience/function with benift (power generated)

with 20% transparency, power generated ~120W/m2, take 4hr average effective sun light, making ~140 kWh/year, peak in summer around 6-7hr, low in winter ~2.5hr (We are at Ontario, Canada)

Cost wise, ~400 USD/m2 (customized fancy color, texture, prints, higher transparency (normally up to 40%), addtional strenth, floor and roof tile, all can do with extra costs)

Plus shipping, shipping is the biggest headache...(full container loading would make economic sense, then we need order volumn/size) And because the high shipping cost, it would be hard to take small residential order to start with...commerical project seems making more sense.

We hope to get some honest feedback of the perspective of BIPV, if we should make this into a business ourselves given the cost and potential revenue room, if going into commercial segment make sense (any suggestion of which sub segment/particular area makes more sense), or residential?(need help and advice in how to make the economic works...) Btw, we are located in Ontario Canada, but US market is as well considered, or should not us? Greatly appriciated!

I'm currently working on an app that takes my roof's solar panel system's actual production from an API, then compares it with the predicted daily sunlight

I'm currently having difficulties with the formula for assessing the actual available production for each day pulling data from different weather APIs but I'm unable to match a number that seems right.

The goal of the app is to allow the user an understanding of when the roof is soiled and the panels need cleaning.

At the moment I do know the panels are soiled but out of the available sunny hours, the app shows around 95% to 97% used production out of the available kilowatts

I do wonder if anyone can help me understand how to properly calculate sunlight potential retroactively and then translate that into the actual available output for a certain day, week, month, and so on

We'd just finished renovating the downstairs rooms of our terraced house in Germany when I went through our electricity readings. I'd been looking at a Jackery SolarVault 3 Pro as a possible home battery and wanted to understand our normal demand. The hire company had collected the drying equipment, but the readings I pulled up still covered the weeks it had been running. I'd almost used that period as our baseline.

We were living there throughout the work, so the house meter included our everyday use as well as the dryers and other work. I asked the hire company for any consumption records from the machines and haven't received a separate figure. I can compare the house readings before and after, but I can't put the entire difference down to the dryers.

I went back to weeks when we were home and no building work was going on. Regular dehumidifier use belongs in that baseline. For storage sizing I also need the timing of our electricity use. How much normal-use data did you collect before choosing battery capacity?

Hi all,

I have a small farm house of 0.6 acres with perimeter of around 1000 feet. The farm currentky has chain link fence with granite posts. The fence is around 4 feet above ground.

As we are experiencing increased menance of monkeys, I am thinking to go for solar fence on top of tge exiating 4 feet high fence. I would like to know on the below -

1. Required wattage and voltage of equipment ( panel, energiser and battery)

   for my farm

2. Which brand shall I go for? My farm is in Andhra Pradesh and looking for good service

3. Approximate cost of equipment

4. Ideas on how to set up solar fence on top of exisying granite poles

5. Best quality cables for solar fencing and approximate cost

I would appreciate any valuable insights

Hi all,

I have a small farm house of 0.6 acres with perimeter of around 1000 feet. The farm currentky has chain link fence with granite posts. The fence is around 4 feet above ground.

As we are experiencing increased menance of monkeys, I am thinking to go for solar fence on top of tge exiating 4 feet high fence. I would like to know on the below -

1. Required wattage and voltage of equipment ( panel, energiser and battery)

   for my farm

2. Which brand shall I go for? My farm is in Andhra Pradesh and looking for good service

3. Approximate cost of equipment

4. Ideas on how to set up solar fence on top of exisying granite poles

5. Best quality cables for solar fencing and approximate cost

I wpukd appreciate any vamuable insights

Curious if anyone here in Texas has had solar installed by Solartime USA or has experience working with them.

I'm interested in hearing how the overall process went, especially when it comes to communication, installation, equipment, and any support needed afterward.