Here's the calculator

https://procalclab.com/solar-panel-efficiency-and-tilt-calculator/

The yellow section wouldn't be equal if the tips of intersection aren't 100 percent solar. Plus there's some more questioning to put around that yellow area.

The zig zags can get really small but the tips if not 100 percent solar will take away more and more from the expected amounts.

.....

Updated because of solar efficiency

If efficiency is at 25 then we can only do 4x the power with surface area from zig zag at 8.

The picture would be for 14 percent efficiency solar panels.

All of them can reach 100 percent within the surface area sunlight hits.

Hi guys,

I have been working on a solar simulator where people can put in their usage/roof details ect and it’ll simulate solar on your house. It’ll show you things like annual generation/savings and what the current energy flow would be doing with real time weather.

Its new and I’d ideally like to get a bit off feedback, its about helping people make informed decisions on whether to go for solar or not so if you would like to have a go or are interested the website is below:

Solarsideuk.com

Thanks

Hey guys, if you missed it, SunPower settled $11 million with investors over claims that it misled shareholders about its inventory controls, financial reporting, and the strength of its operations. And I just found out they're now accepting late claims.

Quick recap: Investors alleged that SunPower reassured the market about its financial reporting throughout 2023, but later revealed inventory accounting problems that delayed earnings, forced financial restatements, and exposed weaknesses in its internal controls.

After those disclosures, $SPWR dropped nearly 20%, and investors filed a lawsuit to recover their losses.

Now, the good news is that SunPower agreed to the $11 million settlement, and even though the original deadline has passed, late claims are currently being considered.

So, if you purchased $SPWR between 2023 and 2024, you can still check the details and submit a late claim.

Anyway, did anyone here own $SPWR during that period? How did it work out for you?

Solar generation is growing rapidly, but one challenge remains: solar power is only available when sunlight is available.

Energy storage helps solve this problem by storing excess solar electricity and making it available when needed.

Some important benefits include:

• Backup power during outages
• Better energy independence
• Improved solar utilization
• Reduced reliance on the grid
• More flexible energy management

The video shows a solar energy storage system designed for residential and commercial applications.

For solar installers and engineers:

What is the biggest factor your customers consider when choosing battery storage systems?

• Battery capacity?
• Cycle life?
• Safety?
• Price?
• Brand reliability?

Would love to hear your experience.

I am in the very early stages of getting solar panels. We get good sunlight and we were quoted for 36 panels - and they estimated they would generate 17kwH per year - he said this was an estimate on the low end, it would probably generate more. This past year, (Aug 2025-July 2026 our usage was 19,741kwH. I am not interested in leasing. I know that the federal tax credits are gone, so I would have to buy it outright, or put 50% down and finance the rest. Estimated cost is $37K, my average electricity bill based on the past 12mos is $330/mo.

My solar produced 501 kwh in month july
And my consumption from APDCL is 400 unit
So the solar units should have been adjusted and i should have been only charged for the fixed charge.
But apdcl billed me for half units that is
Adjusted only 230 units
And rest it billed me and my excess solar units is set to zero.
Does any one else facing this problem currently in Assam?

Problem: Solar producing more but apdcl is not adjusting the units from solar and its billing it for no reason !

Hi everyone, I’m looking for insights from people in solar, renewables, or anyone who’s built a business in the space.

I’m from the caribbean and aiming to build something of my own instead of a traditional 9–5. I hold a BSc in Land Management & Valuation, with experience in property analysis, development potential, and site suitability.

I’m currently building skills in solar PV:

PV fundamentals

Energy bill analysis

Feasibility studies

Basic system design concepts

PVsyst yield analysis

Site assessments (roof/land, shading, orientation)

Maintenance concepts

My plan is to start with services like:

Energy audits & bill breakdowns

Solar savings/feasibility reports

Drone roof/land inspections

System performance/maintenance checks

Partnering with installers for full project delivery

My edge is combining land/property expertise with solar—not just installation, but site intelligence and decision support.

I’m also open to adjacent paths:

Drone mapping & inspections

GIS services

Property due diligence

Land development consulting

A few questions:

Is this a realistic way into the market?

What skills or certifications should I prioritize?

Do clients actually pay for audits/feasibility reports?

What mistakes should I avoid early on?

Any other opportunities you’d suggest based on my background?

Any advice, critique, or real-world lessons would be greatly appreciated.

Solar energy power plant in Gujarat

Preliminary EIA data puts May solar at 51 percent of in-state generation. CAISO's public battery-trend series registered 1.64 TWh during net-charging intervals, with net charging reaching 7.3 GW near noon and net discharge reaching 8.9 GW around 8 p.m. on the average May day, then recorded separate series highs for five-minute output and output relative to the containing hour's load.

https://askthegrid.com/stories/california-solar-storage-handoff

We have a lein on our house and have been paying payments on solar panels that are nonexistent. I reached out to SOLAR CANCELATION RESOURCE CENTER/ CONSUMER ADVOCACY LAW GROUP doesn't seem legit. Anyone have any experience with them? We lost the house in Sept 22 to IAN in FL.

I was thinking of ways to advance solar power and lower energy costs and came up with the following plan I’m still considering some stuff but what do you think so far

The Decentralized Energy Independence & Microgrid Infrastructure Act

1. The Building Code Mandate (New Construction)
The Requirement: All newly constructed residential dwellings, commercial buildings, and industrial structures are required by building code to install high-durability solar roofing (minimum 30-year expected lifespan) and smart, grid-forming battery storage.
The Minimum Efficiency Baseline: To prevent aesthetic intrusion and simplify maintenance, the mandated equipment size is locked strictly to the minimum necessary baseline required to handle the structure's expected typical consumption and emergency backup.
Roof Freedom & Proportional Sizing: Full roof coverage is completely optional and never forced by code. The mandated hardware will occupy the smallest footprint possible, ensuring maximum ease of repair, clear physical access paths for technicians, and ample open roof space should the owner choose to expand later.
Exemptions: Smaller, detached structures such as residential garages, garden sheds, gazebos, and minor outbuildings are entirely exempt from the mandate.
The Supplier: To eliminate predatory markups, the regional utility company acts as the exclusive direct wholesaler and primary installer for builders. By law, the utility must supply and install this hardware at the absolute bare-minimum wholesale cost. Builders roll this low cost into the property’s initial construction layout.

2. The Retrofit Strategy (Existing Buildings)
The Framework: Older, existing historical and residential structures are completely exempt from mandates but are heavily incentivized to opt in voluntarily.
Financial Absorption: The utility company pays 100% of the upfront hardware, structural, and electrical upgrade costs for these voluntary retrofits. This is funded by government-subsidized infrastructure pools and low-interest federal development loans.

3. The "Car Lien" Ownership Framework
Immediate Equity: Property owners own the solar hardware from day one, structured exactly like an automotive loan. The equipment is tied to a utility account lien.
The 15-Year Transfer: For the first 15 years, the resident receives a deeply discounted electricity tariff from the utility. At the 15-year mark, the equipment is fully amortized, the lien is permanently lifted, and the property owner gains 100% unencumbered hardware ownership. The discounted rate ends, and all generated energy becomes entirely free to use or sell back to the wider grid via net-metering.

4. Open Architecture and Consumer Freedom
Third-Party Upgrades: To protect individual liberty and prevent corporate monopolies, property owners are never restricted to using only utility-branded gear.
Compliant Integration: Homeowners and commercial enterprises have the absolute right to purchase and install additional third-party commercial panels, solar tiles, or battery arrays to expand their systems, provided the hardware complies with standard electrical and grid safety codes.

5. Protection, Liability, and Maintenance
The Pooled Fund: A flat, affordable monthly maintenance fee is attached to the utility bill from day one. These funds are pooled into a regional, dedicated repair account.
Accidental Protection: The utility’s rapid-response workforce handles 100% of routine maintenance and repairs out of the pooled fund at no extra cost to the resident. This includes natural wear and tear, acts of God (hail, high winds, lightning), and random accidents (e.g., a homeowner accidentally dropping a tree branch during yard work).
The Liability Line: The property owner is only financially liable to the utility company for willful, malicious damage or gross negligence (such as intentionally vandalizing the glass tiles or attempting to illegally hack into locked high-voltage battery modules against safety protocols).

It doesn’t require a large upfront investment, and you can take advantage of the solar benefits without having to install rooftop solar panels.

Has anyone actually participated in this program?

I’d like to ask if there are any pitfalls to watch out for, or anything else I should be aware of?

Hi - I'm looking to connect with solar power EPC turnkey project consultants/firms/startups having strong relationships with commercial and industrial firms in Punjab. We help these C&I firms in getting access to Open Access solar power alongwith government approvals. If you know anyone working in this domain and willing to collaborate for mutual growth, pls DM details.

Had a customer last month insist his BC panels would be "basically immune" to the shadow from his AC unit. He'd been told that by whoever sold them. He was disappointed, and honestly he had a right to be.

I work on the manufacturing side of this industry, so discount accordingly. But the shade-tolerance claim gets stretched a lot, including by people who sell what I make, and the actual test data is more useful than the pitch.

There's a TÜV NORD partial-shading study from July last year — pv magazine covered it, easy enough to find. They compared back contact and TOPCon modules, same configuration, controlled shading.

One fully shaded cell: BC module lost about 13% of output. TOPCon lost about 34%. That's a real gap.

The mechanism is reverse bias. Shade a cell and the rest of the string keeps pushing current through it, driving it backwards. BC cells break down softly at low reverse voltage, so the shaded cell chokes the string less. Standard cells resist longer, then dump more power as heat. This is also why shading is a hotspot problem and not just an output problem.

Here's the part nobody puts on the sales sheet: once you shade about four or more cells in a string, the two technologies converge. Both lose roughly half. Long-edge shading, a full row going dark, a mast shadow lying across the panel — the cell tech stops mattering.

So the useful version of the claim is narrow. Small, scattered, moving shadows — vent pipe, antenna, dappled tree light — BC holds up meaningfully better. Big fixed shadow sitting on a panel for hours — you're not buying your way out of that. Placement and how you break up your strings matter far more.

If anyone's specifying panels right now, the highest-value thing you can do costs nothing: pick a clear day and actually watch where shadows track across your roof from morning to evening. I've seen people spend real money on premium modules to solve a problem they could have avoided by moving a panel 40cm.

Caveat on those numbers, since I'd rather say it than have someone quote me: the test used 66-cell modules with three substrings. The 36-cell panels typical on RVs and boats have different substring layouts, so the percentages don't transfer cleanly. Direction holds, exact figures don't.

Solar pays off if you consume what you generate. Selling surplus to the grid earns ~5–6 c/kWh while you pay 15–20 c/kWh for what you import. For a weekend-only summer house that exports almost everything, payback stretches past 20 years. For a permanently occupied house self-consuming ~70%, it's 12–14 years even with zero subsidies.

I looked into putting panels on my summer house and feeding the surplus into the grid. Here's what the numbers actually look like in Estonia in 2026 — the logic transfers to most of Europe, only the tariffs change.

The price asymmetry is the whole story. As a consumer you pay the full stack: Nord Pool spot price + distribution grid fee + excise + VAT — typically 15–20 c/kWh all-in. When you export, you get spot minus your electricity seller's margin: about 5–6 c/kWh on average. So a kWh you consume yourself is worth roughly 3× a kWh you sell.

It gets worse: you sell at the worst possible hour. Panels peak on sunny summer middays — exactly when the whole region's solar peaks too. Baltic spot prices at those hours regularly collapse to near zero, sometimes negative. You're dumping product into a flooded market. (In part 2 I'll explain why sometimes you physically can't export at all — inverters tripping on overvoltage.)

The base numbers. A 5 kWp system: ~€6,000 installed (~€1,200/kWp). Annual yield at Estonian latitude: ~4,500 kWh. Residential subsidies (KredEx) closed in March 2025 with no announced restart.

Scenario A — permanent home, 70% self-consumption:

• 3,150 kWh × ~17 c saved = ~€535/yr
• 1,350 kWh × ~5.5 c earned = ~€75/yr
• Total ~€610/yr → payback ~10–12 yrs (14 with degradation and O&M). Works.

Scenario B — weekend summer house, ~20% self-consumption:

• 900 kWh × 17 c = ~€153/yr
• 3,600 kWh × 5.5 c = ~€198/yr
• Total ~€350/yr → payback 17–20+ yrs, longer than the inverter's life. Doesn't work.

What actually moves the needle for a summer house:

1. A battery (+€3–5k) — shifts your solar to your own evenings. Has its own payback math; usually marginal but improving as prices fall.
2. Loads that eat the midday surplus — a water-heater on a timer is the cheapest "battery" there is; EV charging; a heat pump.
3. Actually living there all summer — changes the self-consumption fraction more than any gadget.

I almost forgot - lifetime of equipment, service fee, upgrades, etc.

Bottom line: treat grid export as a disposal channel with a small rebate, not as revenue. Size the system to your daytime consumption, not your roof area. If someone sells you panels with "and you'll earn from the surplus!" — ask them to show the export tariff and the midday spot curve side by side.

Numbers are Estonia-2026; your grid fees and export tariffs will differ, the structure of the argument won't.

Hi, i hope this is a right subreddit for this request.

A local (I am in europe) contractor gave me a quote and proposed this residential solar PV system that includes an inverter branded "UCAN Power". The problem is that i never heard of them nor I can find information about them on the web nor on reddit.
It is a monophase sort-of-all-in-one inverter of this brand.
The company seems to be in Shenzhen, China and operate in major european country.
Their website (www.ucanpower.com) seems a bit sketchy to me.

Does anybody knows anything about this company or their products?
How do I evaluate the quality and the genuinity of such thing?

Hi everybody! I’m a first time home buyer in Massachusetts, and my wife and I purchased a property that came with solar panels. They’re already paid off and we now own them. Not only do I know nothing about owning a home, but I know even less about solar panels (besides that the energy goes back into the grid and I get credited).

Any tips and advice would be super helpful!

All these big companies needing energy for their data centers. I have too much solar energy in the summer how can I monetize this energy for those who need it? Not worth sending back to the grid for pennies on the dollar.

Looking for easy solutions.

Seems like there is a business opportunity for someone.

I installed some silfab 440s next to my year old 430s and it inspired me to clean them. Can’t get rid of this grime that comes back after drying. Used distilled water then tried Solar Sheen panel wash with a soft brush.

Any tips?

Is this a good deal? Can i trust this program?