Am I making a big mistake? Half cut solar panel decision

[kolek]

About to order solar panels and I cannot afford to make a mistake.
Please double check this is a decent reasonable choice for my inverter.

Inverter: Deye SUN-8K-SG01LP1-US

Deye SUN-8K-SG01LP1-US/EU Inverter

Max PV watts is 10,500 watts
Max input voltage is 500V

Solar panel I'm considering is this HALF-CUT 455 watt panel: Longi LR4-72HPH-455M (quantity: 18)

Monocrystalline solar panel 455W LR4-72HPH-455M | DMM エナジー

Technical Datas Module Type：LR4-72HPH-455M Maximum Power (Pmax)：455W Open-circui...

energy.dmm.com

Maximum Power Voltage(Vmpp) for these panels is: 41.7V

Questions:
1. Will these solar panels work with this inverter?
2. I was planning on hooking them up 9S2P, so each string will be 375V (less than the 500V max on the inverter), good choice? And total watts for all the panels will be 8190 watts which is less than the 10,500 watt max for the inverter. (Unfortunately I have a 200 yard cable "home" run back to my house from the only sunny area I can put these).
3. Is there any disadvantage to the half-cut panels I'm overlooking? For example, do they require twice as many connections/cables per panel as regular panels?

Thanks everyone in advance for reviewing this!

 

[timselectric]

To calculate max string voltage , you need to use the VOC. Which on those panels is 49.5v.
So 9 in series is 445.5v (before temperature adjustments) which could be fine, if it doesn't get very cold in your location.

 

[kolek]

To calculate max string voltage , you need to use the VOC. Which on those panels is 49.5v.
So 9 in series is 445.5v (before temperature adjustments) which could be fine, if it doesn't get very cold in your location.

Thank you for catching that error!!
It does snow and freeze on occasion.
The minimum average temp here in January is 3.1C or 38F
To be safe, should I reduce it to 2 strings of 8 panels?
I'm not sure if it applies to input voltage as well, but the Deye salesguy said to keep the total watts well below the limit to maximize the lifespan of the inverter.

 

[timselectric]

8 would be safer.

As far as wattage,
It's a compromise between max production and longevity of equipment. Running at full bore creates heat. Sustained heat can degrade equipment.
Similarly
I can run fast for a short distance, but I can walk all day long.

 

[kolek]

Does anyone have an opinion about the half-cut panel choice, or the company Longi Solar?

 

[timselectric]

I don't have any experience with half cut cells, sorry.

 

[meetyg]

Does anyone have an opinion about the half-cut panel choice, or the company Longi Solar?

I have 2 of the Longi 455w half-cut panels for almost a year now. They are performing OK, but I don't have much to compare to.

The maximum I am able to pull from them is around 360w each, at full sunshine (at least according to my DEYE Sun 2000w GTI).
I measured solar irradiance according to the panel's angle, and got 1200w/ meter squared.

I'm not sure if this is good output, or if the inverter's MPPT algorithm isn't utilizing the full potential of these panels.
Or maybe it's the hot climate (~30-36° C during summer) that's affecting these panels.
During spring the output was almost the same.

Anyways, the Longi are probably in the same class as Trina, Jinko, etc...

 

[Solar Guppy]

Does anyone have an opinion about the half-cut panel choice, or the company Longi Solar?

Half Cell mono is the best available cells, I have 28 ( unknown actual brand, white label from SanTan ) running for 1.5 years now and they are the best performing panels I have ever owned ( been in solar 20 years ). The 395W weigh less than the 275W Poly's almost same size, helps when roof mounting!

 

[DThames]

I have 2 of the Longi 455w half-cut panels for almost a year now. They are performing OK, but I don't have much to compare to.

The maximum I am able to pull from them is around 360w each, at full sunshine (at least according to my DEYE Sun 2000w GTI).
I measured solar irradiance according to the panel's angle, and got 1200w/ meter squared.

I'm not sure if this is good output, or if the inverter's MPPT algorithm isn't utilizing the full potential of these panels.
Or maybe it's the hot climate (~30-36° C during summer) that's affecting these panels.
During spring the output was almost the same.

Anyways, the Longi are probably in the same class as Trina, Jinko, etc...

I have a grid tied micro inverter system and also an AIO secondary system for emergency and testing. This secondary system has 3 different arrays, 2 different types of panels, and three different chargers (2 AIO and an EPEver AN). I don't think I have ever seen the battery system load the panels like the grid tie system does. The grid tie can demand and consume max power all day long. The battery system is very load and battery SOC dependent (of course). I have tried taking the battery down and testing only one array and if I get about 90% of rating, I am doing well. Just my experience trying to get rated panel power.

 

[kolek]

I have 2 of the Longi 455w half-cut panels for almost a year now. They are performing OK, but I don't have much to compare to.

The maximum I am able to pull from them is around 360w each, at full sunshine (at least according to my DEYE Sun 2000w GTI).

Thanks for that feedback.
Shouldn't solar cells supply closer to their rated power?
How are you wiring them in terms of serial / parallel?

 

[kolek]

Half Cell mono is the best available cells, I have 28 ( unknown actual brand, white label from SanTan ) running for 1.5 years now and they are the best performing panels I have ever owned ( been in solar 20 years ). The 395W weigh less than the 275W Poly's almost same size, helps when roof mounting!

That's good to hear. What inverter are you using with those?
Also, how are you wiring them in terms of serial / parallel?

 

[BradCagle]

Thanks for that feedback.
Shouldn't solar cells supply closer to their rated power?

They rarely do. I typically see 75% of the rated power. I think most people see about the same on avg.

 

[timselectric]

It's a very rare occasion to get rated output from solar. Cold day, cloud edging, just after a light rain, with full sun, at the optimal angle.

 

[DThames]

Thanks for that feedback.
Shouldn't solar cells supply closer to their rated power?
How are you wiring them in terms of serial / parallel?

Understand that the rating is under very specific conditions. They are not conditions you find in the real world for the most part. Not impossible conditions, just not normal nor common for most people.

 

[DThames]

It's a very rare occasion to get rated output from solar. Cold day, cloud edging, just after a light rain, with full sun, at the optimal angle.

Right, you need two axis tracking, a cooling unit for the panels, no clouds, and no haze, then all is good!

 

[OzSolar]

Shouldn't solar cells supply closer to their rated power?

Research STC vs. NOCT

Some modules publish both ratings on thier spec sheets.

 

[meetyg]

M

Thanks for that feedback.
Shouldn't solar cells supply closer to their rated power?
How are you wiring them in terms of serial / parallel?

My micro inverter has 4 separate MPPT inputs, so each panel is wired to an input.
Series connection would be over acceptable voltage for one single input.

Solar panels are rated at "ideal" conditions (called STC). For example temperature of STC is 25 degrees Celsius. In real world conditions they output less than rated, usually.

 

[kolek]

The other option I have for a panel is this one:

JA Solar JAM72S-20-460-MR 460W Solar Panel MCS

The JA Solar JAM72S-20-465-MR 465W solar panel with MCS certificate is assembled with high-efficiency PERC cells, the half-cell configuration of the modules offers the advantages of higher power output, better temperature-dependent performance, reduced shading effect on the energy generation...

www.zerohomebills.com

But we do get a little shade, so I just assumed the half-cut would perform better.