EG4 6500ex Max PV output 6.8k instead of 8k

[NewGuyNoob]

Hey Guys/Gals,

I have a EG4 6500ex currently charging my 6x EG4lls Pro [with LCD] batteries. My EG4 6500 120V AC inverter is not "on", as I am not using AC out, just as a battery charger.

Why use it for just charging? [[ I was setting up for split phase]] Well one of my 6500's blew up - internally [magic smoke came out at 20'ish mins of operation, I was present when it happened] and I am awaiting a RMA from Signature Solar. Crap happens, UGH! My understanding is SS are out of EG4 6500ex's anyway, so I am going to have to wait a while for the replacement. I am currently off grid completely and using a Growatt 12K inverter, for AC INPUT via Generator and Output is handled by the 12K Growattt. The 12k maximum PV input is 7KW and outputs from experience, around 6.5KW.

Signature Solar is aware I am off-grid completely. I experienced faults with the Growatt 12K and SS allowed me to keep the faulty one as I awaited the RMA to come in. That way I was not out of power waiting for the replacement to come in. Bottom line is that I purchased the 2 x EG4 6500's to replace the Growatt 12K I'm still using.

Signature Solar was pretty cool about the whole thing @BenFromSignatureSolar, so thanks to SS still keep the lights on! So thanks SS!

So while I wait for the RMA to replace the EG4 6500ex, I have a question from those of you that have experience with these inverters. I looked into the manual for EG4 for power de-rating due to temperature and it seems I am being throttled/de-rated.

The ambient temperature is about 22C/72F. The inverter maximum output in charging the battery is 120A, I am getting approximately 114/115amps max, the remainder of the input is then clipped. The inverter reports it is currently operating at 77c. The manual has a temperature de-rating chart: attached

LINK: EG4 6500Ex Manual





So my question is:

What is your experience? If the maximum PV output is 6.8kw of the DC Charging System is de-rated [on a good cool weather day] what is the point in claiming 8K PV output? Also note, I am not at maximum of my solar panels, I am being clipped, just an FYI.

Have I got this correct? Or am I missing something?

I read the chart above as clipping is expected to occur above 85c @ 18 amps.
Any other interpretations or am I just mistaken?

 

[sunshine_eggo]

You sure those temps aren't in °C - like all the others in that manual?

You have multiple limitations. Power isn't explicitly one of them in many cases.

Relevant MPPT ratings:
PV input current limit
Battery charger output limit.

You're getting 95% of your charger output (114-115A out of 120A).

That then has to be multiplied by your battery voltage to get power. The only time it's even possible to get 8000W out of that unit is when battery voltage is 8000W/120A = 67V.

I'm not seeing anything wrong here.

 

[NewGuyNoob]

You sure those temps aren't in °C - like all the others in that manual?

You have multiple limitations. Power isn't explicitly one of them in many cases.

Relevant MPPT ratings:
PV input current limit
Battery charger output limit.

You're getting 95% of your charger output (114-115A out of 120A).

That then has to be multiplied by your battery voltage to get power. The only time it's even possible to get 8000W out of that unit is when battery voltage is 8000W/120A = 67V.

I'm not seeing anything wrong here.

I would like to agree with you, however yesterday I got between 7.8/7.9KW from my array, which was clipped as well.

Today, not so much, as we are discussing an almost 1KW drop in output. Below is yesterdays power (it was quite cloudy). Today is a full sun day..... so I am being de-rated somewhere as the output max of 120amps is achievable by this inverter IMO. But I am below the rating as indicated above. I would not believe a temperature chart in F would be anywhere acceptable for a de-rating schedule, the machine just being switched on would raise the temperature above 22c, I would think. But I supposed it can be possible, however it does not explain below:

It was cooler yesterday (cloudy and rainy), but data was not collected for inverter temperature. An update to the beta of the software - Solar Assistant - now allows temperature capture from the inverter, well for me anyway.

 

[sunshine_eggo]

That looks like cloud edging effects where your panels briefly put out more because they were cool. Once the sun started heating them, their output tapered off to about 7000W - about what today's PV power shows.

Note also that in your own linked image, you have 6873W of PV power, but you have only 6113W of battery power. Where's the extra 750W going?

Again, that unit has a 120A output limit. As demonstrated in the image, you're only getting 6113W out of the array and you're getting 95% of rated.

I don't see anything wrong... except for the disparity between PV output and battery charging. Makes me question the accuracy of all of it.

 

[NewGuyNoob]

That looks like cloud edging effects where your panels briefly put out more because they were cool. Once the sun started heating them, their output tapered off to about 7000W - about what today's PV power shows.

Note also that in your own linked image, you have 6873W of PV power, but you have only 6113W of battery power. Where's the extra 750W going?

Again, that unit has a 120A output limit. As demonstrated in the image, you're only getting 6113W out of the array and you're getting 95% of rated.

I don't see anything wrong... except for the disparity between PV output and battery charging. Makes me question the accuracy of all of it.

Hey!

I am using the missing power in my household. As this data posted above is just from the 6500ex, as I’m using it solely as a battery charger. The data doesn’t account for the growatt.

The growatt 12k is powering the home via the same set of batteries. Also keep in mind the image posted, showing the inverter - is todays power, it is 6.8kw output.

Interesting take on cloud edging effects. I need to read up on that! But the logic is there as you have stated, I can grasp the concept.

Should I still loose 1kw of reported output capacity due to cloud edging? That sounds a bit much. I have 6kw of panels to each MPPT. I wouldn’t think that heated panels (22c ambient) would remove 2kw of capicity from my panels. I know they will get much hotter than 22c, but that’s the baseline.

I was using my growatt for close to a year. It’s maximum PV input is 7k (2x 3500). My PV output of the growatt was around 6500 or so daily. I would have expected similar results here.

 

[sunshine_eggo]

Hey!

I am using the missing power in my household. As this data posted above is just from the 6500ex, as I’m using it solely as a battery charger. The data doesn’t account for the growatt.

HUH? The only way you're using them as loads is if they're powered by the EG4.

EG4 sends to batteries. Batteries send to Growatt. Only 6100W is being sent to batteries. How is the extra power bypassing the battery?

The growatt 12k is powering the home via the same set of batteries. Also keep in mind the image posted, showing the inverter - is todays power, it is 6.8kw output.

Still doesn't explain how that power is getting to the Growatt via the battery.

Interesting take on cloud edging effects. I need to read up on that! But the logic is there as you have stated, I can grasp the concept.

Pretty simple. Panels perform more like their NOCT/NMOT rating in real-world conditions - about 70-80% of rated because the cell temps are typically 110-130°F even when it's 75°F outside. If you cover the sun with clouds, allow the cells to cool and then suddenly hit them with full sun, BOOM! power spike.



See that 3591W PV charger number? That's from an array rated for 2970W. Cloudy and cool today.

Should I still loose 1kw of reported output capacity due to cloud edging? That sounds a bit much. I have 6kw of panels to each MPPT. I wouldn’t think that heated panels (22c ambient) would remove 2kw of capicity from my panels. I know they will get much hotter than 22c, but that’s the baseline.

Check the NOCT/NMOT rating for your panels.

I was using my growatt for close to a year. It’s maximum PV input is 7k (2x 3500). My PV output of the growatt was around 6500 or so daily. I would have expected similar results here.

No. It's maximum PV is 60A x 2, or 120A. You don't seem to understand that this is a HARD limit. At no time can the MPPT output more than 120A.

If your battery is at 54V, 54V * 120A = 6480W.

Per your image above at 54.1V, the max you can pull from PV is 54.1 * 120A = 6492W.

Again, you're 95% of maximum rated output. You need to get it out of your head that this is a 8000W MPPT. It's not. It's a 120A MPPT.

Your new equipment is performing within 5% of your old equipment. Sounds like noise to me.

 

[Zwy]

450V x 18A = 8100W

That's why it is rated at 8000W.

You have 199.5V x 17.5A = 3491.25W

Each SCC is rated for 4000W times 2 = 8000W

Do you see why you can't input more watts? You are hitting close to the max amps for PV input. It will clip it. Increase volts and wattage will increase to the max 4000W and then it will clip input. The PV array should have higher voltage and less amps.

Amps create heat due to resistance in any circuit. You need to get your PV to a much higher voltage; as close to 450VOC without exceeding the hard limit of 500VOC in colder temps.

As for clipping in higher temps in the chart, quite possible if you're running near the limit on PV input amps. Again, amps create heat, increasing voltage will decrease amps.

Concerning the 120A output, that is what it is rated for.

You have 2 choices, live with it as PV is currently configured or reconfigure to increase PV voltage and decrease the amps. The latter may get you closer to the 4000W each SCC is rated for. The latter will also decrease power loss due to wire resistance in the PV circuit.

 

[NewGuyNoob]

450V x 18A = 8100W

That's why it is rated at 8000W.

You have 199.5V x 17.5A = 3491.25W

Each SCC is rated for 4000W times 2 = 8000W

Do you see why you can't input more watts? You are hitting close to the max amps for PV input. It will clip it. Increase volts and wattage will increase to the max 4000W and then it will clip input. The PV array should have higher voltage and less amps.

Amps create heat due to resistance in any circuit. You need to get your PV to a much higher voltage; as close to 450VOC without exceeding the hard limit of 500VOC in colder temps.

As for clipping in higher temps in the chart, quite possible if you're running near the limit on PV input amps. Again, amps create heat, increasing voltage will decrease amps.

Concerning the 120A output, that is what it is rated for.

You have 2 choices, live with it as PV is currently configured or reconfigure to increase PV voltage and decrease the amps. The latter may get you closer to the 4000W each SCC is rated for. The latter will also decrease power loss due to wire resistance in the PV circuit.

Thank you for the responses.

I did not clarify myself very well. I understand the hard limit imposed is 120 amps total for this unit. 60 amps per SCC.

My current solar panel setup was wired for the 12k which has an input limit of 250v max. That is why these solar panels are still wired this way, as it is an existing solar panel field. I do plan to set this up as 8s2p each string- later on. (I have 32 x 370w solar panels)

I do believe I have enough solar panels to provide plenty of current for the SCC to hit their output limits.

My current solar panel setup:

A single panel is = 370w / Imp =9.28a Vmp=39.9

This is one string, to one SCC:
5s3p = 199 volts x 27.84 amps. (15 x 370w panels).

30 solar panels in total, 2 strings of 199.5v x 27.84 amps.

So, that is = 5,554.08 watts for each 4kw SCC.

11,108.16 total watts to the 2 SCC’s in the EG4 5600ex.

Maximum solar performance is never attained I know, but I believe I have enough of a “solar panel battery” for the SCC’s to draw from.

My understanding is:
Solar power is not pushed into the SCC’s. The SCC’s draw energy from the panels. When the SCC can not draw any further enegry - imposed SCC limit or not enough energy available to the SCC- “clipping” occurs. Correct me if I’m wrong, please.

So to restate: I am at 115 amps output via the image above. Please note the output is not reaching 120 amps combined. so, this means to me - that each SCC is clipping its input power. (Unknown watts really due to unknown solar panel string performance)

I’ll have to dig through my data later.

So if this is true:
—The SCC’s are clipping prior to reaching 120amps max output.

Perhaps my understanding is not correct. Which is ok. That’s why I’m here to clarify my understanding and figure out what is going on.

If the combined output is not producing 120 amps at maximum capability - then either we do not have enough input, or we have a SCC restriction (de-rating) or simple inability of the controller to perform at that limit.

So :
I believe I have enough input to the SCC’s.

I have seen the controller output 120 amps combined.

I feel like I’m being de-rated… so why?

Is this correct or am I misunderstanding? What’s your thoughts?

Also, Do not take this as an ego challenge, I’m not here to boost your ego by being challenged or to compare brain pans. I’m not stupid nor do I know everything.

I’m just wanting to learn and discuss what I’m seeing.

I would like to believe I am not loosing 1.5kw in each strings performance. Which would be necessary to justify what I am seeing.

Of course I can definitely be wrong!

Ask the wife!

 

[NewGuyNoob]

HUH? The only way you're using them as loads is if they're powered by the EG4.

The growatt is pulling power from the batteries and inverting that to my house loads. That is why power is “missing” from the battery meter. The battery meter is coming from the BMS of the batteries. So they see a loss.

EG4 sends to batteries. Batteries send to Growatt. Only 6100W is being sent to batteries. How is the extra power bypassing the battery?

Pretty simple. Panels perform more like their NOCT/NMOT rating in real-world conditions - about 70-80% of rated because the cell temps are typically 110-130°F even when it's 75°F outside. If you cover the sun with clouds, allow the cells to cool and then suddenly hit them with full sun, BOOM! power spike.

View attachment 111609

See that 3591W PV charger number? That's from an array rated for 2970W. Cloudy and cool today.




Check the NOCT/NMOT rating for your panels.

No. It's maximum PV is 60A x 2, or 120A. You don't seem to understand that this is a HARD limit. At no time can the MPPT output more than 120A.

If your battery is at 54V, 54V * 120A = 6480W.

Per your image above at 54.1V, the max you can pull from PV is 54.1 * 120A = 6492W.

Again, you're 95% of maximum rated output. You need to get it out of your head that this is a 8000W MPPT. It's not. It's a 120A MPPT.

Your new equipment is performing within 5% of your old equipment.

I disagree. The old equipment clipped the panels at 3250 watts or so. The new equipment is supposed to do 4kw each SCC. And I’m not seeing that. I wonder if it is due to that much loss in panel performance??



There is supposedly 1k per unit difference per EG4. A total of 2kw worth of energy potential.

Do solar panels really underperform such as that?

 

[Lt.Dan]

You're getting 95% of your charger output (114-115A out of 120A).

That then has to be multiplied by your battery voltage to get power. The only time it's even possible to get 8000W out of that unit is when battery voltage is 8000W/120A = 67V.

I didn't get to read through this whole thread because I'm short on time right now, so forgive me if this has been said, but I'd like to add to this; Yes, 120a going into the battery is not a full 8000w, but you can USE the remaining power not going into the battery. Eg, if the battery is 55v X 120a, = 6600w, and if you could theoretically produce more than 6600w from PV, then that excess power can go towards powering loads.

 

[sunshine_eggo]

The growatt is pulling power from the batteries and inverting that to my house loads. That is why power is “missing” from the battery meter. The battery meter is coming from the BMS of the batteries. So they see a loss.

Does the circled information come from the EG4 or some other source?

I disagree. The old equipment clipped the panels at 3250 watts or so. The new equipment is supposed to do 4kw each SCC. And I’m not seeing that. I wonder if it is due to that much loss in panel performance??

You're just not listening. These aren't 4000W MPPT. Period. They are 60A MPPT output limit with 450V and 18A input limits.

4000W/18A = 222V - Your operating Vmp must be this or higher.

4000W/60A = 67V - the minimum battery voltage you would need to deliver 4000W to the battery.

You should see ZERO difference in the performance of your PV vs. your Growatt. Period.

I didn't get to read through this whole thread because I'm short on time right now, so forgive me if this has been said, but I'd like to add to this; Yes, 120a going into the battery is not a full 8000w, but you can USE the remaining power not going into the battery. Eg, if the battery is 55v X 120a, = 6600w, and if you could theoretically produce more than 6600w from PV, then that excess power can go towards powering loads.

Are you absolutely certain of this? Do you have any documentation to support this. I'm not trying to be a dick, but this is counter to both intuition and logic. It implies there's some separate circuit direct from PV to loads. The panels are connected to the MPPT. How does the MPPT send additional output to the inverter? It's not directly converting high voltage DC to AC. It's converting high voltage DC to low voltage (battery) DC. if it could send that "extra" current to the DC input of the inverter (loads), why couldn't it also send it to the battery, and how does it even know the difference? Why is there any limitation at all on the charger then?

FWIW, the OP stated he is using this strictly as a MPPT. No AC output.

Somebody explain to me how this works:



EG4 is somehow sending the surplus 700W around the battery to the loads.

 

[Zwy]

Thank you for the responses.

I did not clarify myself very well. I understand the hard limit imposed is 120 amps total for this unit. 60 amps per SCC.

My current solar panel setup was wired for the 12k which has an input limit of 250v max. That is why these solar panels are still wired this way, as it is an existing solar panel field. I do plan to set this up as 8s2p each string- later on. (I have 32 x 370w solar panels)

I do believe I have enough solar panels to provide plenty of current for the SCC to hit their output limits.

My current solar panel setup:

A single panel is = 370w / Imp =9.28a Vmp=39.9

This is one string, to one SCC:
5s3p = 199 volts x 27.84 amps. (15 x 370w panels).

30 solar panels in total, 2 strings of 199.5v x 27.84 amps.

So, that is = 5,554.08 watts for each 4kw SCC.

11,108.16 total watts to the 2 SCC’s in the EG4 5600ex.

Maximum solar performance is never attained I know, but I believe I have enough of a “solar panel battery” for the SCC’s to draw from.

You are hitting close to the max amps input of the SCC. Until you lower the amps by increasing the voltage it most likely will not attain the max performance you are looking for. The SCC is limiting the input due to the amps. It probably wouldn't matter if you have 10,000w of PV available to just one SCC; with the current configuration, it will still clip the amps.

As Eggo stated, "4000W/18A = 222V - Your operating Vmp must be this or higher."

My understanding is:
Solar power is not pushed into the SCC’s. The SCC’s draw energy from the panels. When the SCC can not draw any further enegry - imposed SCC limit or not enough energy available to the SCC- “clipping” occurs. Correct me if I’m wrong, please.

The SCC puts a load on the PV by allowing current to flow. The SCC has a limit on the amperage it can convert to a different voltage than the PV.

So to restate: I am at 115 amps output via the image above. Please note the output is not reaching 120 amps combined. so, this means to me - that each SCC is clipping its input power. (Unknown watts really due to unknown solar panel string performance)

I’ll have to dig through my data later.

So if this is true:
—The SCC’s are clipping prior to reaching 120amps max output.

I'm not disagreeing that clipping may be occurring, the reason why it may be clipping is due to incorrect configuration of PV.

Just because you have more PV watts available doesn't mean the SCC will pull those watts from the PV.

Perhaps my understanding is not correct. Which is ok. That’s why I’m here to clarify my understanding and figure out what is going on.

If the combined output is not producing 120 amps at maximum capability - then either we do not have enough input, or we have a SCC restriction (de-rating) or simple inability of the controller to perform at that limit.

So :
I believe I have enough input to the SCC’s.

I have seen the controller output 120 amps combined.

I feel like I’m being de-rated… so why?

Is this correct or am I misunderstanding? What’s your thoughts?

Above in bold.

Also, Do not take this as an ego challenge, I’m not here to boost your ego by being challenged or to compare brain pans. I’m not stupid nor do I know everything.

I look at this as merely an exercise into what and why, ego has nothing to do with it.

I’m just wanting to learn and discuss what I’m seeing.

I would like to believe I am not loosing 1.5kw in each strings performance. Which would be necessary to justify what I am seeing.

Of course I can definitely be wrong!

Ask the wife!

 

[Lt.Dan]

Are you absolutely certain of this? Do you have any documentation to support this. I'm not trying to be a dick, but this is counter to both intuition and logic. It implies there's some separate circuit direct from PV to loads. The panels are connected to the MPPT. How does the MPPT send additional output to the inverter? It's not directly converting high voltage DC to AC. It's converting high voltage DC to low voltage (battery) DC. if it could send that "extra" current to the DC input of the inverter (loads), why couldn't it also send it to the battery, and how does it even know the difference? Why is there any limitation at all on the charger then?

FWIW, the OP stated he is using this strictly as a MPPT. No AC output.

Somebody explain to me how this works:

View attachment 111636

EG4 is somehow sending the surplus 700W around the battery to the loads.

Hmm, now that I have slept on it, I realize what you are saying, the MPPT is limited to 120a, meaning it can't overfeed that through to the inverter side. I am mistaken.

Makes you wonder why they are advertising the 8000w rating, when the charger can only go up to 62v. 62v x 120a is still only 7440w.

 

[Vigo]

It's possible that when operating at full 120a it is that inefficient and 8000w are going into it. Should be able to tell by the fan airflow whether the unit has become 'a space heater on a low setting' when doing 120a and the rest of it is coming out as hot air. ?

Very believable as i have a 500w space heater under my desk and i would say my Growatts operating at max are blowing something similar out. VERY rough subjective comparison, i know.

 

[NewGuyNoob]

You are hitting close to the max amps input of the SCC. Until you lower the amps by increasing the voltage it most likely will not attain the max performance you are looking for. The SCC is limiting the input due to the amps. It probably wouldn't matter if you have 10,000w of PV available to just one SCC; with the current configuration, it will still clip the amps.

As Eggo stated, "4000W/18A = 222V - Your operating Vmp must be this or higher."

The SCC puts a load on the PV by allowing current to flow. The SCC has a limit on the amperage it can convert to a different voltage than the PV.


I'm not disagreeing that clipping may be occurring, the reason why it may be clipping is due to incorrect configuration of PV.

Just because you have more PV watts available doesn't mean the SCC will pull those watts from the PV.

I think my understanding is incorrect then. As you and @sunshine_eggo have been pointing out. However if I don't grasp the "why", then I simply wont fully understand what you both are trying to explain to me.

My initial belief was: The SCC would "transform" any additional amperage provided into "higher voltage/amperage" to provide power up to its maximum rating. So long as voltage and amperage provided was within its operating range.

I need to study up on this, so I am missing approximately 22 volts or so, I have the amperage, but not the Vmp min required. Is the above statement - is this the correct way to approach this?

So:

I look at this as merely an exercise into what and why, ego has nothing to do with it.

I do as well, that was a general statement as some individuals can become quite aggressive or assertive and seem to take things personally when being disagreed with. This statement was not applicable directly to anyone, as I believe you both are aware of. I just want to make clear that my intent and statements are just to further my understanding, even if I disagree with anyone- this does not mean Im right, im fully aware and accept if I am wrong in my assumptions.

I only ask to know why I am wrong, usually this means my understanding is flawed or I -one of us- do not have all the information involved.

FWIW, the OP stated he is using this strictly as a MPPT. No AC output.

Somebody explain to me how this works.

Does the circled information come from the EG4 or some other source?

@sunshine_eggo

The information circled I do believe comes from the EG4LL Pro BMS. However I am not 100% on this, as I have only been using this system for solar charging only three days now. I am just now getting used to where the information is and I have been trying to validate the data against what I see directly from the batteries and buses that I have measured. The information provided is similar to the growatt, but there are a lot of differences as well.

To explain the physical setup of the equipment:

A pair of 4/0 battery cables connects from the battery rail to a (pos and neg) buss bar. This battery connection style causes a T's setup. To the left side of the battery buss bar is the - EG4, which the battery is connected via 2/0 cables. The right side of the buss bar connection has the Growatt 12K, via 2/0 cables as well. The solar strings are connected to the EG4 only, and the Growatt 12k does not have any solar input connected, just battery connection.

My current solar panel setup: [This was my Growatt 12K setup, 250v max input]

A single panel is = 370w / Imp =9.28a Vmp=39.9

This is one string, to one SCC:
5s3p = 199 volts x 27.84 amps. (15 x 370w panels).

30 solar panels in total, 2 strings of 199.5v x 27.84 amps.

So, that is = 5,554.08 watts for each 4kw SCC.

11,108.16 total watts to the 2 SCC’s in the EG4 5600ex.

I have observed that any loads the Growatt provides, correlates to the battery input displayed in the Solar Assistant Panel. The battery panel will display outputs that are close but approximately [-] negative 750 watts ~ 1200 watts depending what is running in my home. This is my basic static draw which is what I have observed for the past year.

The Battery Panel meter is provided by the EG4ll Pro Battery BMS. This is directly read by a Rs485 connection to these batteries. I also believe the Signature solar battery metrics are provided by the BMS as well, but I am not certain that this is the case.

I have seen the solar charge controllers output approx 750w without charging the batteries [they were 100%] to provide power to the growatt 12k for inverting my loads.

So question:

I chose to charge at 57v, this should be CV. Does this metric also change the SCC behavior for charging, as you stated this below:

You're just not listening. These aren't 4000W MPPT. Period. They are 60A MPPT output limit with 450V and 18A input limits.

4000W/18A = 222V - Your operating Vmp must be this or higher.
4000W/60A = 67V - the minimum battery voltage you would need to deliver 4000W to the battery.
You should see ZERO difference in the performance of your PV vs. your Growatt. Period.

4000/60A = 66.66v, I am not following this metric and how this applies to a 51.2v battery system. I would like to discuss this to better understand what is being said.

4000/18A = 222v, that would require me to rewire as I believe we are already stating. Can the SCC not transform 200v 30amps into max power required? I don't have the basic concept of how a SCC functions, but I had belived the MPPT would/could change Voltage and Amperage and use the best combination for maximum power.

Thanks for all the responses~!

 

[NewGuyNoob]

It's possible that when operating at full 120a it is that inefficient and 8000w are going into it. Should be able to tell by the fan airflow whether the unit has become 'a space heater on a low setting' when doing 120a and the rest of it is coming out as hot air. ?

Very believable as i have a 500w space heater under my desk and i would say my Growatts operating at max are blowing something similar out. VERY rough subjective comparison, i know.

This is this mornings performance above:

Also here is the chart:

 

[Vigo]

6918 - 70 (system electronics) - 6179 = 669w 'missing'. Inverter is 73c (wherever it's checked, or may already be calculated as some kind of aggregate) aka ~165f.

So if you take the case fans on high, point them at a 165f radiator in a ~80 degree room (assumption on my part), how many hundreds of watts of heat do you conduct into the air? Definitely some of it. How much? I dunno. ?

 

[NewGuyNoob]

View attachment 111635

Does the circled information come from the EG4 or some other source?



You're just not listening. These aren't 4000W MPPT. Period. They are 60A MPPT output limit with 450V and 18A input limits.

4000W/18A = 222V - Your operating Vmp must be this or higher.

4000W/60A = 67V - the minimum battery voltage you would need to deliver 4000W to the battery.

You should see ZERO difference in the performance of your PV vs. your Growatt. Period.



Are you absolutely certain of this? Do you have any documentation to support this. I'm not trying to be a dick, but this is counter to both intuition and logic. It implies there's some separate circuit direct from PV to loads. The panels are connected to the MPPT. How does the MPPT send additional output to the inverter? It's not directly converting high voltage DC to AC. It's converting high voltage DC to low voltage (battery) DC. if it could send that "extra" current to the DC input of the inverter (loads), why couldn't it also send it to the battery, and how does it even know the difference? Why is there any limitation at all on the charger then?

FWIW, the OP stated he is using this strictly as a MPPT. No AC output.

Somebody explain to me how this works:

View attachment 111636

EG4 is somehow sending the surplus 700W around the battery to the loads.

Here is what I was speaking about, my batteries are completely charged and the EG4 6500 is not providing any power to the batteries. The Growatt 12K is inverting from the battery to the loads. This is how that is shown in Solar Assistant display.

 

[sunshine_eggo]

I think my understanding is incorrect then. As you and @sunshine_eggo have been pointing out. However if I don't grasp the "why", then I simply wont fully understand what you both are trying to explain to me.

My initial belief was: The SCC would "transform" any additional amperage provided into "higher voltage/amperage" to provide power up to its maximum rating. So long as voltage and amperage provided was within its operating range.

You can't pick and choose ratings:

4000W rating.
18A max input rating.
450V max input rating.
60A output rating.
61V max output limit.

You can't ignore ANY of the above. If ANY hit max, that's all you're going to get.

You can't ignore the power equation, Power = voltage * current, ALWAYS

You can NEVER input more than 18A FROM the array to the MPPT.
You can NEVER output more than 60A FROM the MPPT to the battery bus.

From that you can calculate things:

Power = Voltage * Current
4000W = Voltage * 18A

Input: Voltage = 4000w/18A = 222V thus Array must be at least 222Vmp to hit 4000W INPUT.

Output: Power = 61V * 60A = 3660W

This tells you that you can NEVER get 4000W out of the MPPT because your battery voltage can never output higher than 61V.

Some other considerations.

1. Ratings have tolerance. Solar panels themselves are typically ±3%. Any of these numbers may vary by ±1-3% depending on construction quality.
2. MPPT are not 100% efficient. This unit is claimed 93% efficient. To get the calculated 3660W max, you'll need AT LEAST 3660/.93 = 3935W of array.

If the battery data is being reported by the BMS, then it's NET. This would account for the "missing" power. if the values are reported by the EG4, then the "missing" power is from inefficiency.

 

[Vigo]

the "missing" power is from inefficiency.

We should all be so.. dang comfortable!

"Invert and chill"