Am I maxed out?

[Mr2Ducks]

I'm running a Schneider 6448 (6.4k / 48v.) inverter. Two MPPT 600's. Batteries and Grid Tied (to sell back).

I had 22 of my new 400 watt panels working (11 to each controller). I've been seeing a high of 6.31Kw on the inverter at what I would call peak sun (around noon).
That as calculated gave me just under 600 v. open circuit using the multiplier for cold weather. Now that it's warming up with nighttime lows in the 50's, I thought
I would hook up two more panels and check the results. So 12 and 12 on a string. I had 28 panels on the array with the last 6 not connected.

To my surprise, the next two days watching the inverter display, the highs I would be seeing was 6.29 to 6.31. It stayed there from about 11am to 2pm.

You can get up to 10k out of that inverter for a short period of time. Thinking it was 20-30 minutes. Sliding scale to the 6.4k where it's continuous.

I figured, adding another 800 watts I would now see about 7k on the inverter. It never went higher then 6.31.

I have 9600 watts of panels. My MPPT's were at one point harvesting 3226 and 4322. Combined that's 7548. Inverter only showing 6.3k. It;s in grid sell status.
I know there are losses. This is about 20%.

Can the 6448 only accommodate 6.4k of panels? The excess the MPPT's were showing selling back to grid?

Does adding these panels only give me more power generation before and after peak sun where I max out at 6.31k?

Not the result I was expecting having been told by a Scheinder installer he regularly adds more panels. But maybe this is the result
of doing that, I just was expecting to see more inbound watts displaying on the inverter.

 

[Daddy Tanuki]

maybe you are hitting the max amps that your units can put out, and they are shaving power as a result?

sorry just spitballing.

 

[Supervstech]

Yeah, the point to overpaneling is to get as much energy as the controllers can collect in poor conditions.

There will be missed output in high seasons.

 

[hwy17]

I'm confused why you are looking at the inverter about your solar input.

Your inverter's output is defined by your load demand.

 

[Supervstech]

I'm confused why you are looking at the inverter about your solar input.

Your inverter's output is defined by your load demand.

On grid tied, it is always 100% demand though, right?

 

[hwy17]

On grid tied, it is always 100% demand though, right?

Oh I see, they are selling. That does just sound like inverter limit then. They never made a 6448 in the US, maybe in 230v version.

It does sound like it's the inverter continuous limit then, either way.

 

[Mr2Ducks]

Yeah, the point to overpaneling is to get as much energy as the controllers can collect in poor conditions.

There will be missed output in high seasons.

That's kind of what I was thinking. I've heard the term overpaneling before. Do you think it's sending the excess to grid or is it,
as someone else said, shaving it off? I'm all about turning that meter backwards when I can.

 

[Brucey]

That's kind of what I was thinking. I've heard the term overpaneling before. Do you think it's sending the excess to grid or is it,
as someone else said, shaving it off? I'm all about turning that meter backwards when I can.

The inverter is going to have a fixed output limit, no matter how much solar you are feeding it or the battery bus.

Overpanelling is for example connecting say 8-10 kW of panels to a 6kW scc, so you have a better chance of utilizing that 6kW controller in winter when you aren't going to be hitting 100% output.

 

[G00SE]

How are your strings oriented? A dozen 400w panels in series is surely a significant VOC
As stated above, if you were pulling 8-10kw the inverter should handle it but I doubt it will overload itself to sell more energy to the grid

 

[Mr2Ducks]

The inverter is going to have a fixed output limit, no matter how much solar you are feeding it or the battery bus.

Overpanelling is for example connecting say 8-10 kW of panels to a 6kW scc, so you have a better chance of utilizing that 6kW controller in winter when you aren't going to be hitting 100% output.

that makes sense. Thanks.,

 

[Mr2Ducks]

How are your strings oriented? A dozen 400w panels in series is surely a significant VOC
As stated above, if you were pulling 8-10kw the inverter should handle it but I doubt it will overload itself to sell more energy to the grid

11 in series per controller.

I don't recall the exact calculations, but the 11 panels was under the 600 VOC max on the CC using the cold weather multiplier
which was somewhere around 1.2. I think I figured down to about Zero F. Adding the 12th was still under VOC max if not using the
multiplier which with the warmer temps shouldn't need to.

If I see clipping, I'll go back to 11.