Aurora Inverter PVI-3.6 TL

[Birder]

My above named inverter is misbehaving...... for approx. 10mths it's worked OK but now it switches off in bright sunlight ( works OK in other conditions) and displays the error.... Input OV. This is displayed until the bright sun goes and then it picks up again and works OK. In it's display routine it indicates that the "Inverter is OK" but why should it not work in bright sunlight....? Has anyone got experience with this situation please....? Birder

 

[whinmoor]

What panels do you have? How many?

 

[Birder]

What panels do you have? How many?

Hia, thanks for the reply, The only info I have on the panels says they are JA Solar and there are 16 of them fitted in a single string. Hope that's OK.

 

[SibertSolar]

Are you sure it's not 2 strings of 8 panels? 16 panels on one string doesn't sound ideal to me for the PVI-3.6....Are they 250W poly? What's the rough pitch and orientation?

 

[whinmoor]

How many DC isolators do you have? Could you post a few pictures of the set up?

Have you contacted your original installer? What was the response?

 

[taffbutc]

Agree with SibertSolar. 2 strings of 8.

 

[SibertSolar]

I suspect that the peak kW output of the panels at high irradiance is too high for the 3.6 unit, depends on the panels themselves but if they are anything bigger than 235Wp then that could be your problem....

 

[whinmoor]

They could be 250w monos. It sounds like a re-stringing operation will be required.

First port of call should be to the original installer to complain. They may suggest replacing the inverter but that's unlikely to solve the problem as it's the system design at fault, not the components.

 

[SibertSolar]

^^agreed, best talk to your original installer

 

[Gavin A]

I suspect that the peak kW output of the panels at high irradiance is too high for the 3.6 unit, depends on the panels themselves but if they are anything bigger than 235Wp then that could be your problem....

absolutely no chance of that, if anything it'd be overvoltage as indicated by 'Input OV', but those inverters will take 5kWp no problem, they just derate via the MPPT voltage point if necessary.

I suspect they've run it in single string, which is just about inside the voltage range at low light levels, but at higher light levels in cold weather the voltage goes over the voltage limit and inverter cuts out.

This is an installer / design issue, it should never have been installed single string, so they need to be got back and switch it to 2 strings, assuming this is what it is.

What is the strong voltage reading when it does work?

 

[taffbutc]

Given that it has been in for ten months and only now had this problem i dont think its 1 string. Did you checnk for
isolation valves? Can you produce pictures if not?

 

[whinmoor]

Maybe he's only just noticed the problem but it's been going on for ages ?

Photos would certainly help.

 

[SibertSolar]

It does sound like low-temp, high irradiance, excessive upper MPPT voltage issue though, doesn't it....

 

[taffbutc]

Whinmoor- That i possible but i feel he has been watching it. He said it had worked ok. If this has been there a while his Kwh should be lower than expected.

Sibert - i agree to MPPT voltage issue however same thing. 1 string would have highlighted this issue well before now

 

[SolarRoofSols]

If it has been installed on 2 strings, which it should have if they are higher wattage panels, then could it be that there is a surge in the grid which is shutting the inverter down??

If this is the case then the installer should be able to liaise with the DNO and manually change the settings in the inverter.

You really need to determine whether 1 or 2 strings though, as others have said.

 

[FB.]

Is it just the freakishly cold weather combined with quite favourable sun angles? A unique combination of quite high irradiance, near-optimal sun angles and the temperature coefficient going in reverse.

We're looking at once-in-fifty-years cold weather for this time of year, but the sun is now in its strongest half of the year and late-morning it's getting close to shining directly (perpendicular) onto SE-facing panels at 40 degrees.

In recent days, when there was a glimmer of sun between the broken cloud, I was surprised at how much power was being produced even when the sunshine was very hazy.

 

[Gavin A]

I'm a little baffeld about why there is any debate about what the fault is tbh - rule 1, check what the fault code means if you don't already know.

Input OV // E002 Input Overvoltage

so it's an input over voltage fault as I and others stated, and the reason it's happening now is because the system was right on the limit and has been pushed over it by the cold bright weather with the sun at a relatively optimum angle.

max voltage input is 600V
16 x 37Voc = 592V

So bearing in mind that most of the year the inverter will kick in at relatively low light levels, when the voltage is correspondingly lower, it's not just possible, but extremely likely that the system will have worked fine until you get the right combination of extreme cold and blue skies / sun at the right angle to combine to give a voltage of over 600V.

tbh, having dismissed the over power issue earlier though, I do wonder if they've made this mistake whether they've even put the jumpers across the inputs to allow for the power from a single string in one input or not, so there could well have been some serious limiting going on if they hadn't.

Get the installers back and slap their wrists for making a rooky error - may well be worth asking them to replace the varistors as a precaution as they may well have been damaged. Don't be too harsh with them though as long as they sort it out without issue, as we all make the odd mistake now and then, and it's very close to being inside the spec.

 

[sedgy34]

They could be 250w monos. It sounds like a re-stringing operation will be required.

First port of call should be to the original installer to complain. They may suggest replacing the inverter but that's unlikely to solve the problem as it's the system design at fault, not the components.

They could change the inverter to a kaco 4000 that takes 1 string of 16 upto 800vdc
if they go that route

 

[FB.]

Don't be too harsh with them though as long as they sort it out without issue, as we all make the odd mistake now and then, and it's very close to being inside the spec.

Yes, at this time of year we'd expect temperatures on sunny days to be quite a lot warmer, with the temperature coefficient causing a consequent de-rating in output rather than a boost to the output which is the case recently!
Rather like the Titanic: all should have been fine and the design wasn't too bad; being good for 99% of likely situations. Unfortunately, a bizarre, highly unexpected event happened and the 1% chance came up!
(actually, this is reported as the coldest spring in fifty years, which makes it a 2% chance)

 

[Birder]

Yes, I'm right with 1 string and yes, they are 250w poly. Pitch is 30 degrees and slightly east of due south orientation

 

[sedgy34]

Yes, I'm right with 1 string and yes, they are 250w poly. Pitch is 30 degrees and slightly east of due south orientation

As suggested earlier you either need an extra string wired from the panels to make 2xstrings or change inverter

 

[Birder]

Thanks to each and everyone for this excellent debate and advice. I've discussed it with the installer and he's sending his man to investigate. Is it ok with everyone to show him these comments and suggestions......? Joe..

 

[sedgy34]

Thanks to each and everyone for this excellent debate and advice. I've discussed it with the installer and he's sending his man to investigate. Is it ok with everyone to show him these comments and suggestions......? Joe..

Of course he may learn something lol

 

[Gavin A]

fine by me.

fwiw, we had precisely this debate at some point about whether or not a 16 panel system would be ok in single string as it'd be more efficient, but I'm pretty sure we've always split the 16 panel arrays on these inverters though for this reason.