Are panels performing correctly?

[Jenx]

I have a 3.9KW system, but it only imports a maximum of 2.8KW - even on a sunny day when there are no couples in the sky!

Could there be a problem with the panels? I assumed that they would import somewhere between 3.6 and 3.9KW or is it normal for a 3.9KW system to import a number so much lower than its capacity?

Thanks in advance for any information or advice.

[bcroe]

Your panel output will be reduced according to your inverter efficiency,
and wiring resistance. Recently smoke from Canada has been having
an impact on IL, USA solar, much more than similar appearing clouds.
Bruce Roe

[Jenx]

Thanks Bruce.

I’m actually in UK.

I was just after a bit of advice as I’m new to it all - no idea about inverters and resistance etc!

just baffled by the import Figures as they seem low for a 3.9 system!

[SunEagle]

Jenx. I responded to your issue in your other thread. To help keep the duplication of answers I would appreciate if you only post your issue once. Thanks

Also if you are going to post in the New Members thread you should provide some additional detail like where you live and what your solar system is comprised of.

[Jenx]

Apologies - took me a while to work the website out!

[SunEagle]

Apologies - took me a while to work the website out!

No apologies necessary. I hope we can help you determine if your problem can be solved or whatever.

[SolTex]

Jenx Hello from TX, USA. As asked in above replies, it would help if you can tell us what model solar panels you have, and how many panels. Also, what is the brand and model number of your inverter. With this info, the experts on this forum can provide more helpful responses to your questions.

I can tell you that some of your confusion is the result of you being provided inadequate information from the sales person or the installer who supplied your system. It should have been explained to you that even though your system is rated at 3.9 kW DC power, it will seldom if ever actually produce that much power. The rated "size" of your system is based on the STC nominal DC output of your panels. The actual size of your system is how much AC power it can produce. This depends, as noted above, primarily on the capability of your inverter. Inverters are typically "undersized" in relation to the DC size of the system. In your case, your inverter may be maxed out when it is producing 2.8 kW of AC power.

Once you provide more details about your system, the forum members will tell you if it is operating properly, or if you have a problem.

[Rade]

I have a 3.9KW system, but it only imports a maximum of 2.8KW - even on a sunny day when there are no couples in the sky!

Could there be a problem with the panels? I assumed that they would import somewhere between 3.6 and 3.9KW or is it normal for a 3.9KW system to import a number so much lower than its capacity?

Thanks in advance for any information or advice.

Hello!

My system has an app for monitoring the home usage, panels, batteries and what is going back to the grid. My inverter is consistently using about 0.2kW to 1kW of power for system management depending on what it's doing (cooling fans, relays firing off, etc.). I've been told that is pretty much standard.

Example - panels are generating 5.14kW, batteries and drawing .12, home is using 1, and 3.75kw are going out to the grid., my inverter is using around .27kW of power.


. Screenshot_20230919-132420.jpg

Rade

[J.P.M.]

I have a 3.9KW system, but it only imports a maximum of 2.8KW - even on a sunny day when there are no couples in the sky!

Could there be a problem with the panels? I assumed that they would import somewhere between 3.6 and 3.9KW or is it normal for a 3.9KW system to import a number so much lower than its capacity?

Thanks in advance for any information or advice.

Before you assume a problem with your system, get some quick self education.
1.) Download and read a free PDF of : "Solar Power Your Home for Dummies". It's a bit dated but for the most part the information is still valid. There isn't much new under the sun with respect to the basics, even for PV.
2.) After the "Dummies" read and not before, download something called PVWatts. It's a solar PV model from NREL. Read all the help screens and info, get the required inputs pertinent to your system correctly input to the model and do a few runs. It's a fairly quick learning curve if you've read the book and understand what the model's help and info screens are all about. Otherwise, it'll be GIGO.

Une thing you'll learn is that your array will most likely never produce its STC rating due to many factors. You didn't supply the necessary info to allow anyone not familiar with your system to offer intelligent opinions about whether or not your system's production might be problematic.
Your instantaneous output will be reduced by several weather variations dealing mostly with atmospheric clearness, time of day and season of year as well as the angle of the beam radiation at which the sun hits your array.

The info you garner from the "Dummies" read and a PVWatts model output that's based on good inputs will give you insights into what your array's expected output might be.
See what you learn and then come back here and ask questions your info gathering generates that you can't then answer on your own.

Welcome to the forum of few(er) illusions.