Inverter 400V DC Shutting off limit?

It seems that apart from the AC GRID VOLTAGE restriction I have put in to the system I have also found that the unit is switching off when the panels are producing 400V DC. having two strings of total 22 panels at 345W each can someone tell me if the 400DC is correct as I am under the impression this setting should have been 500V

any gurus out there like to help please

You will need to reference the data sheet for your particular module. The data you should look for would be the parameter Voc which is the open circuit voltage of the panel. This number multiplied by the number of modules in a string (I think this is 11 in your case unless I’m reading your statements above incorrectly) would be your maximum string voltage. If you are in a cold climate, you would probably also need to use the Temperature Coefficient for Voc (Tkvoc). To do this, subtract STC temperature (25°C) from the minimum temperature at your location during the day (lets assume 0°C) and then multiply by the Voc Temp Coefficient (-0.29%/°C for example) to get the correction factor.

So your max voltage is VocModules in String(1+(Tamb-25)(Tkvoc)/100). If your Voc is 30V, then Max Voc=3011(1-(0-25)(-0.29)/100)=30111.0725=355 V.

Just use the actual values from your module data sheet and you should be able to get your max voltage.

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The Panels manual is telling me the Voc open cct voltage is 68.2V and I have 22 of those as I am in normal climate beeing in Melbourne not hot or cold… my calculation are wrong as I am missing something here … the inverter can take upto 600 V can you tell me what the mac VOC should be ?

A) 14 panels 345w each with 500 optimisers
B) 8 panels 345 w each with 500 solaredge optimisers

The Power Optimizers add a wrinkle to the issue and I’m just not familiar enough with them to answer your question. I think you would be better off speaking with your installer or with SolarEdge technical support directly.

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Solaredge change the country profile so this 400V is gone away however there is some major throttling which limits the output power of the inverter when the AC grid riches 250V and the system switches off at 265V
my normal gird voltage is always at 250 to 253 thus the system never produces peak power I wish to find out how to change this internally which will give me a little more juice which I need to operate

If anyone know the setting or where to look for this limit will be fantastic…

I have been comparing your output to others in your area on the same days. It looks like your inverter may be experiencing what is called ground fault failures which is caused by inadvertent grounding within you PV installation at a so-called blind spot. Comparing one other system in your area indicates similar power curves throughout the day.
It seems that in the later afternoon and when there are no cloud shadows your system seems to perform as expected. When there are large swings in power seems to be the times you system acts up. Can’t say much beyond that.
There may be other issues with your string configuration which is highly unbalanced with 14 panels on one string and 8. My system is smaller at 6.3 kW on two strings of 10 and 11 of 300 watt LG panels with a SE7600A-US inverter. Grid power is 120/240 V split phase 3 wire. Operating voltage varies little from 268 to 374V.

Thank you for this vital information.
Is there anyway I can find out a little more about the ground failure ? how do you detected as I need to go back to the installer or solaredge to report… can you assist m,e to see how you found this issue which I can explain to them?

Also the solaredge system due to its design ability with the power optimisers is the only system that can mismatch the strings … I was told that the 500 series optimisers can handle and balance the load for the system I have.
Looking forward to your assistance on the rest so I can go back to them…

As new country setup profile has been installed only a week a go which now does not cause the unit to switch off at 250V however the throttling is there I am sure and the unit is not what it use to be.

Hi Tony, if your main inverter has a shut of DC input voltage of 480 v aus spec max then any voltage above this is chocked of by the inverter, so your 14 x 68.2 volts= 954.4 volts is never reached, this means that almost 50% of the aver able energy is wasted.also Australian standards state that 600 V DC is the max voltage for a house solar system, it seems odd that a installer would install a system that is not to aus specs,but then i have come across this before with a Australian wide installer that was installing thin film panels in string of 6 at 105.4 v each, they had to go out and change a lot of systems to string of 5 in series to meet the the 600 Volt DC rule.
your system may have been better if your panels were installed in too strings of 5 P and 6 Panels in parallel.
this works well with the 500 optimizers you have and would give you about 3.8 kw and 405 volts per string,
i have a similar system to this and it works very well,
mine has Jinko Maxim panels with the 3 maximizers built in to each of the cell strings in the panel. hope this helps and that i miss read your data and your system is all good.

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I installed my system which was designed by an online seller. They did an excellent job and the system produces about 2X my annual usage and yields a small payout at the end of the one year true-up period. Since my inverter is oversized and could handle another 1 kW of panels if I choose, it never clips the production. Voltage is very stable and regularly converts all available irradiance to power. I have a split array with 5 panels on a NE orientation and the other 16 panels on a SW orientation. However, my two strings are 11 panels on the SW side and the other string split between SW and NE with 5 on each side. There is a slight penalty for splitting the string but the design accommodates that. The NE facing panels produce a little more in the morning than the SW facing panels and they pull down the production of the other five SW facing panels when they go into shade in the afternoon hours. During mid Summer the produce close to equal power producing about 2 kWhs per panel in either orientation. However, in mid Winter the NW facing panels produce only 1/2 that of the SW facing panels. The production you gain would well outweigh the losses you are now experiencing now.
You might want to rewire the strings to make them more balanced and avoid the over-voltage.
Ground faults may be unlikely in a newly installed system but it may be worth looking at. Try this link:
If you have a clip-on current meter you can check for current in the neutral wire if you have split phase (or Ground wire if you don’t) (I’m not sure about Australia house wiring). Ideally this current on a neutral conductor will be small if loads are balanced and there are no shorts. Ground wires are intended as a protection against shocks when inadvertent shorts occur in an appliance. The offer a low resistance path to divert current to harmlessly to ground. Inverters are supposed to have arc-fault protection built into their design to prevent the shock hazard associated with them. The inverter will shut down when the event is detected.

Thank you for your input. I did raise this with solar edge and they told me the system is balanced with in specs as the optimisers can take that configuration and that during the design their system passed the strings configuration at the time.
Its very difficult for me to pin point the issue without facts as they trying to run from any issue they have caused by configuring the system wrong which is limiting the power production. I believe the biggest issue is my Grid Ac voltage which is supplied from 250 to 253 and the unit is programmed to throttle the output at 250 and shut off at 265v. I am trying to tell them i need to change the trottling configuration to start later but they are not listening to my calls.

Ps i have never received more that 450DC volts as.per my records so not sure how the strings will even generate 600 volts plus?

Tony, some good news and some not so good news. the new aus spec for grid voltage inverters and the grid supply states that NO new inverter shall be able to output more than 258 volts to the grid, it must also have power modulation when the output go,s past 253 v so sorry you will not be able to turn up your output voltage
if your input supply with no load and NO solar is above 253 v you may be able to get your power provider to fix this for you as its outside the new regs. they did this for me ,had to replace the sky wire and adjust the street transformer as well, had recording gear on my supply for 3 weeks to prove what is said was right.
to perhaps work out what your system is doing i would need all the tec specs and also need to know how many pairs of DC wires are wired into your main inverter, i see that you 500 s have a max output volts of 60 v each and the main inverter says max volts of 1000 volts DC,well in aus thats only 600 v DC as per our regs,so 60v X 14p =840 volts, you say your system has never gone past 450 v so a big volts drop there somewhere, what size DC cable did they use, for 600 v and 5 kw you need 6 mm sq unless its only like 6 mts from the panels to the inverter Jim

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Thank you for your assistance its been very helpful and if you are in Australia I would like to have a chat on the phone with you as I have got a lot of data recorded. if this is possible can you tell me how I can talk to you please?
Today I have spoken once again with solaredge to provide me with their technical feedback…
They told me that the string I have with 14 panels is within specification and it will never produce maximum power since
50% of these panels are looking WS and the other 50% NW and the string can handle the wattage the panels can produce as there is no cut off in the inverter regarding the DC volts.

With in regards to AC Volts which definitely is causing throttling I have spoken with United energy who is the electricity supplier and they are with in the rules to supply continues voltage 10% higher than 230 volts as per regulations it proven my house during production time is running between 250 to 253V … on the other hand the inverter has throttling programed into it to slow down production starting at 250V and cut off at 265V as per the Australian standards.
The DC wire is definitely more than 5 meter however cannot see the cable but I am happy to open the box up and take a photo for you to review. the cable is definitely 20 meters to the longest panel from the inverter. I hope cable is not the issue here.

So my battle is never ending here as I am trying to prove if there is any issues with the strings configuration and then to get solaredge to adjust the throttling program to start at 253V and give me a little room to produce peak power. as ist now starting at 250V as per the industry Australian standard AS777.2

I have taken reports from the system daily and benchmark my unit with 2 others and I am happy to provide the information. I have provided to solaredge all the relevant data to assist but it seem that my case is too hard for them to handle both the point of sales and installer who I am speaking for the last 3 plus months on the inaccuracies I am witnessing with the system.

The only way to beat this system is with hard evidence and knowing how their inverter works otherwise they don’t like discussing technical specification for the obvious reason with the owner. I am exposed to a lot of RED TAPE here!!

hope we can call each other to chat soon!

Tony, yes i am in Australia,please email me at if you included your address i will fire up a satellite tomorrow and have a look at your roof, also anz 4772.2 has be updated it now from 2016 4777.2.2015 max output voltage of 258 v then the inverter should shut down,and yes we can chat on the phone, and yes i would like to look at your data, whats your pvoutput system name mine is jims maxim jinkos 6.625. jim

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Tony, one think i can see from the live data on pv org is that your inverter is being affected by heat, your inverter starts to reduce output from about 46 deg c by the time its at 57 deg c its lost 30% + of its possible output.

i can see when the garage door has been opened and when you have parked the car back in the garage by the inverter temp, i use a infrared thermometer to check mine , even on a 40 deg c day here my inverter only went to 48.6 c

if you look at live data on pv org on the 38/3/18 you will see what i mean at 11.30 the garage door was opened temp went down and then went up after door closed and you power output went down, it should have being going up as your S/W

set of panels was coming on line then.

if you can somehow make it so there is air flow in your garage you will get more power from your system your inverter shuts down completely at 60 deg c so that my be why is shutting down and not from over voltage.

hope this will fix your problem Jim

OK then tony if you don’t believe me then thats all i can do for you,i hope you sort it out


I am about to install an external fan to cool down the unit which will turning on depending on the heatsink temp of the unit. I will start it at 25C and see how we go… hope to have this finished in a week as I am waiting for some parts then lets hope you are correct with the temp issue.

thanks again and keep in touch

Does anyone know if the DC voltage is adjustable? The reason I ask is that I have a string of 10 panels with P370 optimers, 5 east and 5 West panels. In the morning the east optimers are maxed out at 60v and the West at 22.5v. This gives a string voltage of 412v. The problem is the west panels don’t have enough power to match the current of the East panels even with the lower voltage, this causes the east optimisers to clip their output. Lowering the string voltage would be the easiest solution.