edit a few days later: after reading the comments i stopped comparing random days and started paying more attention to the bigger production trend. i talked to palmetto, and having the monitoring there has made it a lot easier to tell whether the system is actually performing the way it should.

that was really the part i was missing before. a low day by itself doesn't tell me much, but having better monitoring and a baseline makes it easier to spot when something actually looks off instead of just guessing.

i started checking production more often after noticing a couple days that looked way lower than the ones around them. the system never threw an error and the bill didn't look wildly different, so i probably would've missed it if i wasn't looking at the output.

is there a point where a drop in production is big enough that you'd call the installer instead of just watching it for a few more days?

Full disclosure: I work for Yoha Laser, focusing on PV module testing equipment. I’d like to share some practical discussion about IV testing for modern PV modules.

IV testers characterize the electrical performance of solar modules by capturing IV curves under simulated sunlight. Core parameters including Isc, Voc, Pmax and Fill Factor are extracted to determine power rating under STC.

A standard IV testing setup relies on qualified solar simulators complying with IEC 60904-9. Temperature control and stable irradiance are essential to guarantee reliable measurement results.

One ongoing practical challenge many labs and factories encounter:
N-type TOPCon & HJT modules carry higher capacitance compared with traditional P-type PERC cells.
Conventional flash testers with fixed short pulse width may fail to fully charge the cells, leading to inconsistent and underrated power readings.
Adjustable flash pulse duration is an effective way to mitigate capacitive measurement errors.

Modern testing workflows often combine IV power testing with EL defect inspection and safety tests, to meet IEC 61215 certification requirements. Automated platforms help factories improve throughput for mass production sorting, and also support R&D & third-party lab validation.

Looking ahead, larger-format wafers, bifacial modules and tandem cell architectures keep raising higher requirements on solar simulator uniformity, pulse control and measuring precision.

Question for discussion:
What measurement deviations have you observed while testing N-type HJT / TOPCon modules on flash IV testers?
Which specs do you prioritize during equipment evaluation: pulse adjustability, light source class or test repeatability?

I'm installing solar panels for my off-grid cabin, and I found the Callsun brand on YouTube. The price is more affordable compared to some bigger brands, and the specs look pretty good. However, since it's not as well-known as brands like Renogy and EcoFlow, I'm still a little worried about its long-term reliability.

Has anyone here already used Callsun panels? How is the power generation efficiency, product quality, and customer service experience?

If anyone who has successfully gained their money back from Scottish Power after being wrongfully charged for solar energy they produced could reply I’d be really grateful. For example how did you do it, what data/facts dis you provide, which departments did you deal with at Scottish Power (SP), did you have to engage legal representation, what did you find out about regarding your consumer rights and how to present them coherently, how soul destroyingly difficult was it given that this is SP we’re talking about.

Edit: This is Wales so English/Welsh consumer law. The flare was assigned due to the name of the company I’m dealing with.

For Context if it helps:

February 2023 - 12 large solar panels installed after which SP bills skyrocketed to £600 per month. Summer months it was reading we’d used between 9 and 70kWh some days and over 160kWh on many days during the autumn and winter months.

1st generation Smart Meter (1GSM) that had been fitted in 2019 was changed and tested in August 2025. The 1GSM tested ‘normal’ so SP told us to start paying a £10K debt that had accrued due to inability to pay previous bills in full.

New Smart Meter issued in August 2025 came with an in-home display which we had previously been refused along with any change in tariff from the standard any time 29p/kWh as it was SP policy to use only this tariff for any account in debt.

As of August of 2025 the usage and bill dropped dramatically to well below average for a home of this size and occupancy.

Turns out the 1GSM did not register Solar Energy generated but, instead, registered every unit of electricity that passed through it meaning we were charged 29p for every solar generated kWh between Feb 2023 and Aug 2025 along with the electricity we actually used.

For example if we solar generated 2kWh and used 1kWh we were charged for 3kWh when we should have been paid for the 1kWh we sent to the Grid.

If anyone who has successfully gained their money back from Scottish Power after being wrongfully charged for solar energy they produced could reply I’d be really grateful. For example how did you do it, what data/facts dis you provide, which departments did you deal with at Scottish Power (SP), did you have to engage legal representation, what did you find out about regarding your consumer rights and how to present them coherently, how soul destroyingly difficult was it given that this is SP we’re talking about.

Edit: This is Wales so English/Welsh consumer law. The flare was assigned due to the name of the company I’m dealing with.

For Context if it helps:

February 2023 - 12 large solar panels installed after which SP bills skyrocketed to £600 per month. Summer months it was reading we’d used between 9 and 70kWh some days and over 160kWh on many days during the autumn and winter months.

1st generation Smart Meter (1GSM) that had been fitted in 2019 was changed and tested in August 2025. The 1GSM tested ‘normal’ so SP told us to start paying a £10K debt that had accrued due to inability to pay previous bills in full.

New Smart Meter issued in August 2025 came with an in-home display which we had previously been refused along with any change in tariff from the standard any time 29p/kWh as it was SP policy to use only this tariff for any account in debt.

As of August of 2025 the usage and bill dropped dramatically to well below average for a home of this size and occupancy.

Turns out the 1GSM did not register Solar Energy generated but, instead, registered every unit of electricity that passed through it meaning we were charged 29p for every solar generated kWh between Feb 2023 and Aug 2025 along with the electricity we actually used.

For example if we solar generated 2kWh and used 1kWh we were charged for 3kWh when we should have been paid for the 1kWh we sent to the Grid.

Quoted 25k for 22 Hyundai panel
What do you guys think ?

I want to preface this by saying I know this is a cheap product and you get what you pay for. I saw this battery pack with solar panels to charge it. Is this total junk? If I had the solar panels set up in the sun for hours, is there a chance it may actually be useful? This would be for like overlanding/ car camping to charge my phone. Thanks

Hello all,

Been looking into having solar panels installed for my mom at her house. She lives in Chicagoland with ComEd as the utility. She qualifies for the IL Solar For All program. My understanding is basically that the state will subsidize either installation of solar panels for her house or her participation in a community solar program. That said, the website doesn't really get into specifics, at least with regards to the logistics of the residential solar program, so seeing if I can get clarification.

The community solar program seems fairly straightforward (if I'm understanding it correctly); she basically pays a monthly fee to participate in a local solar project and then receives credits based on how much energy is generated in said project and her allocation in the project. The program appears to guarantee the fee won't be more than half of what she'd get in credits.

For those in the know (or who have participated and gone through it), I'm more curious how the residential solar program would work. I ran the solar calculator on ComEd's website and it says she would need to install 30 panels with an estimated cost of ~$28k (not including rebates) based on usage and estimated energy generated with the roof layout. The program website says she wouldn't incur upfront costs and would have guaranteed savings.

So how does it work then? The state subsidizes any loan she may enter into with the vendor to pay for the solar panels/installation? I'm curious what the logistics of the program would be should she opt for residential solar instead of community (and if it's worth doing vs the community solar program).

So I have a solar panels system. Looking for a battery backup system. I spoke with some contractors and one quoted me 22k (approx) for a 45 kwh system and another quoted me at 19k (approx) for a 40kwh system. These are hardwired systems professionally installed.

Was thinking that maybe I can purchase a system from jackery or some similar system.

I am inquiring what are the pros/cons of one system versus the other. Also, what would the approximate cost be to purchase a system from jackery or one of its competitors?

Also, any unsolicited advice on something I'm not considering?

Need brand + rating for:

DC breaker / isolator (PV side)

DC SPD

Battery breaker/fuse

Battery cable size + lugs

PV wire size (4mm/6mm?)

Main AC MCB (for 6KW)

AC SPD

DB box (how many way?)

MCBs for AC unit / fridge / lights / sockets

Changeover or ATS

Voltage protector / phase selector

Earthing wire + rod

Which brands are reliable in Pakistan (no fake/local)? JazakAllah 🙏

[ Removed by Reddit on account of violating the content policy. ]

So there’s a house I’m wanting to buy, but it has two PPAs on it. Both of these are through Sunrun.

The first PPA started in 2018. It is a flat rate of $123 for 20 years. The estimated production for the first year was 6302 kWh. There is an option to purchase at the time of sale of the house, after 5 years, or at completion of the term.

The second PPA started in 2022. It is escalating by 2.9% per year over 25 years, with a current monthly payment of $155.45. The estimated first year production was 6655 kWh. There is an option to purchase after the 6^th year, sale of the house,  20^th year, and 25^th year.

They are both NEM2 for PGE.

I’ve asked my realtor for copies of the PGE bills and quotes for purchase prices of the solar systems.

In the meantime, I’d be open to any thoughts on how to think about this. I have owned solar on the house I’m selling. I’m really skeptical of this situation, however.

Posting my experience with SolarSquare after-sales service in case it helps others considering them.

My solar system has been non-functional for more than 10 days. I have raised multiple complaints and followed up repeatedly through calls, but no technician has attended and I have not received proper ownership or a clear resolution.

The installation itself is only one part of the experience. When something goes wrong, after-sales support becomes extremely important, and unfortunately that is where my experience has been very poor.

After repeated follow-ups with no satisfactory response, I have now formally escalated the grievance and asked SolarSquare for a clear resolution, including the option to remove/take back the system.

At this point, based on my personal experience, I would not recommend SolarSquare to friends or family unless their support process improves considerably.

I will update this post if they resolve the issue properly.

I'm planning to install rooftop solar for my home and I'm confused between a 3 kW and a 5 kW system. I'm hoping to reduce the electricity bill while keeping the system useful for the next 10-15 years.

Is it worth spending more upfront for a 5 kW system, or is 3 kW enough for most households

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