New PV+Batteries system underperforming

**SunEagle** · 04-26-2023, 09:01 AM

Sounds like the West facing panels are not wired properly into the inverter. And the issue with the second battery may be because it requires a Master/Slave set up.

I think you are correct in getting the installer involved so they can correct the problems. Keep us informed on how your system performs. Thanks

And welcome to Solar Panel Talk.

**Ampster** · 04-26-2023, 10:24 AM

Originally posted by aluis

.......

However I wonder what could cause this? What is it most likely, that this installer is just clueless or could it be bad parts?

If you are off grid, it could be caused by the one battery being full. If you are grid tied the only limit would be the output of the panels. How are you monitoring the output?

**aluis** · 04-26-2023, 10:51 AM

Originally posted by Ampster

If you are off grid, it could be caused by the one battery being full. If you are grid tied the only limit would be the output of the panels. How are you monitoring the output?

I'm connected to the grid. Monitoring using the inverter manufacturers customer portal. Here's the most recent screenshot. The installer is currently at the house trying to get it working. There's some solar power now but it's very choppy. It's been a sunny day but the generation jumps from several kW to nearly zero.

2023-04-26_15-48.png

**oregon_phil** · 04-26-2023, 10:59 AM

How many panels do you have, what kind are they and are they arranged in two strings connected to the two MPPT inputs? Do you have any shadows on the panels?

**aluis** · 04-26-2023, 11:13 AM

Originally posted by oregon_phil

How many panels do you have, what kind are they and are they arranged in two strings connected to the two MPPT inputs? Do you have any shadows on the panels?

No shadows at all. There are 12 x 455w monocrystaline panels. I believe they're all in the same string.

**solardreamer** · 04-26-2023, 11:44 AM

Does the inverter show any errors? The PV string voltage may be too high.

**oregon_phil** · 04-26-2023, 12:03 PM

I agree. Inverter max voltage 600Vdc, MPPT range 90 to 550VDC.

OP didn't panel specifics but guess 455 watt panel with half cut cells, Voc ~50 VDC = 600 VDC string voltage and maybe higher due to temperature coefficient depending on location.

Panels with lower Voc might be OK.

Disclaimer, I am not an installer.

**aluis** · 04-26-2023, 12:36 PM

Originally posted by solardreamer

Does the inverter show any errors? The PV string voltage may be too high.

I believe you're right. The installer is laying more cable from the roof down as I type, to create a second string. Shouldn't this have been done first time around?

**oregon_phil** · 04-26-2023, 12:46 PM

One would assume the installer is making two strings of 6 but don't assume anything. Inverter has a start voltage of 120 vdc which would be a string of 3 or 4 panels depending on Voc. Just ask the installer what's going on.

**solardreamer** · 04-27-2023, 11:40 AM

Originally posted by aluis

I believe you're right. The installer is laying more cable from the roof down as I type, to create a second string. Shouldn't this have been done first time around?

Are you talking about the same installer that didn't make sure the batteries were working fully before leaving? If so, I think you know the root problem cause.

**aluis** · 04-28-2023, 08:32 AM

Originally posted by oregon_phil

One would assume the installer is making two strings of 6 but don't assume anything. Inverter has a start voltage of 120 vdc which would be a string of 3 or 4 panels depending on Voc. Just ask the installer what's going on.

I confirmed and the strings were indeed split into 6 panels each.

The panels are now producing to full capacity but the problems don't end here.

The second battery was this morning all of the sudden recognized by the system, without any input from the installer. It's great that they now work but I would like to understand how it is possible that the system corrected itself.

The only problem remaining now is that the inverter is throwing 2 errors every couple of hours. They are "Grid Voltage 10 min. Average Overvoltage (energy storage)" and "Battery Open Circuit Warning".

When these are triggered the PV output is shut off and energy from the grid is used instead. After half an hour or so it goes back to producing solar.

The installer is blaming the unstable grid current that's triggering this. Is this true? I find it weird that the grid could shut down my solar production!

**SunEagle** · 04-28-2023, 08:42 AM

Originally posted by aluis

I confirmed and the strings were indeed split into 6 panels each.

The panels are now producing to full capacity but the problems don't end here.

The second battery was this morning all of the sudden recognized by the system, without any input from the installer. It's great that they now work but I would like to understand how it is possible that the system corrected itself.

The only problem remaining now is that the inverter is throwing 2 errors every couple of hours. They are "Grid Voltage 10 min. Average Overvoltage (energy storage)" and "Battery Open Circuit Warning".

When these are triggered the PV output is shut off and energy from the grid is used instead. After half an hour or so it goes back to producing solar.

The installer is blaming the unstable grid current that's triggering this. Is this true? I find it weird that the grid could shut down my solar production!

If your inverter has software that looks at the grid power and does not like what it sees it will turn off for a period of time. The issues could be voltage or frequency from the grid that falls outside the programmed parameters in the inverter. So yes the grid could be causing your inverter to stop.

You might have to contact your POCO and see what is happening on the grid and then your installer to see if the program in the inverter can be loosened up a little.

**oregon_phil** · 04-28-2023, 12:25 PM

Originally posted by aluis

I confirmed and the strings were indeed split into 6 panels each.

The panels are now producing to full capacity but the problems don't end here.

The second battery was this morning all of the sudden recognized by the system, without any input from the installer. It's great that they now work but I would like to understand how it is possible that the system corrected itself.

The only problem remaining now is that the inverter is throwing 2 errors every couple of hours. They are "Grid Voltage 10 min. Average Overvoltage (energy storage)" and "Battery Open Circuit Warning".

When these are triggered the PV output is shut off and energy from the grid is used instead. After half an hour or so it goes back to producing solar.

The installer is blaming the unstable grid current that's triggering this. Is this true? I find it weird that the grid could shut down my solar production!

I don't think you said where you are located.

Australian example: "The grid voltage Australian standard AS 60038 is 230V +10% -6%, which is a range of 216V to 253V. The Australian standard for your inverter instructs that it must disconnect from the grid if voltage exceeds 255V for 10 minutes or exceeds 260V for any amount of time."

Try to search for your country grid's requirements. What specs are used?

Manuals and information on the internet regarding your inverter & battery's troubleshooting information are sparse.

Battery #2 should have DIP switches set different than battery #1. I have to assume your installer knows how to make and crimp communication cables correctly.

Good luck!

Attached Files

DIP Switches.png (38.6 KB, 43 views)

**aluis** · 04-28-2023, 03:02 PM

Originally posted by oregon_phil

I don't think you said where you are located.

Australian example: "The grid voltage Australian standard AS 60038 is 230V +10% -6%, which is a range of 216V to 253V. The Australian standard for your inverter instructs that it must disconnect from the grid if voltage exceeds 255V for 10 minutes or exceeds 260V for any amount of time."

Try to search for your country grid's requirements. What specs are used?

Manuals and information on the internet regarding your inverter & battery's troubleshooting information are sparse.

Battery #2 should have DIP switches set different than battery #1. I have to assume your installer knows how to make and crimp communication cables correctly.

Good luck!

Thanks, I appreciate the info.

I am in Portugal. I'm not sure of the exact specs of the grid voltage but it's definitely in the 200s. The installer said the inverter cutoff because it detected a grid voltage of 250, whic is too high. I have the inverter's manual which doesn't seem to contain parameters to set these limits. I guess these can't be set as they must be within the grids requirements.

Does this mean that I have to live with regular solar and battery cutoffs?

I also saw the DIP switches in the manual, when the second battery first didn't work, which I sent the installer. He just ignored me. He's probably fed up of my suggestions. I'm very disappointed with my choice of installer but too late to change now. And I'm not sure how to approach this without the communication deteriorating further. I still haven't paid for half of the costs. I'm holding on until everything is as up and running as possible. So I appreciate the feedback as I'm not aware of what he can or can't do about the cutting off issues.

Thank you.

New PV+Batteries system underperforming

New PV+Batteries system underperforming

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