peak real-world output of Power One Aurora PVI-3.6-OUTD-UK

[Sunshine777]

My PV system (4kWp of panels with a Power One Aurora PVI-3.6-OUTD-UK inverter) seems to regularly peak at 3608-3610 W. In reading the literature on the inverter I was expecting to see a peak output of 16A which is 3680 watts at 230 volts or 3840 watts at 240 volts. Grid voltage as seen by the inverter is typically 238-242 volts when the system is in full flow. I know the inverter has 3600 in its model name but I’m curious why the output doesn’t match the literature. Any insights appreciated.

 

[moggy1968]

what time of year did you achieve 3610?

 

[Sunshine777]

21 Jan and 7, 12, 16, 18 and 19 Feb - seems too much of a coincidence that it's the same peak value.

 

[Sunshine777]

Here's a graph of today's out - note the definite flattening at 3600

 

[TJLinks]

Where/how do you generate a graph like that?

 

[Sunshine777]

Data extracted from the inverter via Aurora Communicator and then plotted in Excel...

 

[yellowvanman]

My PV system (4kWp of panels with a Power One Aurora PVI-3.6-OUTD-UK inverter) seems to regularly peak at 3608-3610 W. In reading the literature on the inverter I was expecting to see a peak output of 16A which is 3680 watts at 230 volts or 3840 watts at 240 volts. Grid voltage as seen by the inverter is typically 238-242 volts when the system is in full flow. I know the inverter has 3600 in its model name but I’m curious why the output doesn’t match the literature. Any insights appreciated.

Probably something to do with the 'tolerances' of the inverter.

 

[screwdriver]

I take it that you are in the UK and have a nice high south facing steep pitch roof? If so how about giving it a few months until there is a bit more sun I have seen the PVI 3.6 OUTD UK peak at 4015w before on a 3920w system so I wouldn't worry too much!

 

[Sunshine777]

I am indeed: Hampshire, 40 deg roof, 10 degrees east of due south.

Happy to wait a bit but the consistent peak value did make me think there was a ceiling somewhere. I've now gone back and looked at the inverter log files and the DC peak wattage from the panels appears to be roughly 3700 watts so perhaps it all makes sense for the time of year.

 

[screwdriver]

Out of interest, what does your inverter show up as in the communicator? a PVI 3300?

 

[Sunshine777]

Yes, it shows up as a PVI-3.3-OUTD-UK - I understand this is something to go with G83 compliance for the UK.

 

[Graddie]

Hi We have a PVI 3.6 (16amp limited) and are also peaking at 3681W. I am waiting for a response from Power One as I agree that 16A at 240V is 3840W.

Regards

 

[Sunshine777]

What sort of grid voltages are you seeing when those output levels occur?

 

[GaryM]

Hi We have a PVI 3.6 (16amp limited) and are also peaking at 3681W. I am waiting for a response from Power One as I agree that 16A at 240V is 3840W.

Does you local grid deliver 240V or 230V? 3681W at 230V is 16A.

 

[Sunshine777]

In my case when the inverter is outputting 3600 watts the grid voltage it reports is typically 240-243V. On average when the inverter is outputting more than 200 watts the voltage is over 240. At start-up and shut-down the voltage is nearer 235.

 

[Graddie]

Hi

I have a comprehensive reply from Power One.

It appears the answer lies in the tightening of G83 regulation/interpretation - which is that 16 Amps is assumed at a nominal 230 Volts ac. This corresponds to 3.68 Killowatts (kW) on a single-phase supply.
Nominal voltage as stipulated by BS EN 50160 and the Electricity Supply Quality and Continuity Regulations (ESQCR).

So whilst I'm not very happy at this top end limitation; at most it probably means a reduction of 100kwh per annum which at 43p is £43.

I'm interested to know what will happen if all the non 16A limited systems are deemed in breach of regulation eg SMA.

 

[liquidity]

The G83 certificate seems to indicate the inverter can peak at 4000 watts - see http://navitron.org.uk/download_images/download_1280401387_154.pdf

Also interesting to note that some people see 4000 watts from the same inverter - see SMA4000TL or the Fronius3.6TL for a 3.92kWp (16x245w) system advice needed

 

[liquidity]

I find this limitation rather frustrating - Power One appears to have changed the specification of the inverter without telling anyone and it seems they can't be *rsed to update their literature even well after the fact.

 

[liquidity]

To be fair I need to correct the above post - the latest G83 certificate lists the maximum output as 3600 watts - see http://www.power-one.com/sites/power-one.com/files/pvi-3.0_3.6_4.2-outd-s-uk_g83doc_05102011.pdf It's dated 5 Oct 2011.

 

[Fazzathebrave]

So my installers have just put in a Power One Aurora PVI-3.6-OUTD-UK on a 3.91kWp system. Does the G83 certificate and 16A Max output restriction that I see on the nameplate mean that I will lose the extra power at the top end on a sunny day? I thought it was curious when I saw a flat profile one sunny day recently. Should I ask them to fit the 4200?

 

[liquidity]

If the output curve won't go above 3600 or thereabouts then your inverter is holding back the panels. As I understand it PVI-3.6-OUTD-UK inverters with a serial number greater than 621395 are affected this way.

If you ask to have a 4.2 fitted your installer may need to apply under G59 rather than G83. No harm in asking I suppose.

 

[Fazzathebrave]

My Aurora has a much larger serial number wk 47 2011.
I think I'll monitor the situation for a while as it's not often up at 3.6kW at the moment. Hoping for sunny days ahead! I guess when the sun is not at the strongest then I'm still getting the benefit of having a larger system installed, and that is most of the time.

 

[screwdriver]

We aren't quite getting into the right time of year for peak outputs of your panels so I would hold back until it is definitely clear that the inverter is restricting output, I am sure these are clamped at 16amps which depending on your grid voltage could be anywhere around 3680w to 4000W. If you did want to go down the G59 route then you may be able to update the firmware on the inverter via a registered installer so that the 16amp limitation is removed, to be honest I don't think that overall you would notice a worthy increase in annual yield to justify the hassle.
You have to remember that these inverters were brought out specifically for the UK market to allow installers to comply with G83 recommendations and so there will be a slight compromise to reach that as was so with fitting the larger sma inverters and restricting outputs to 16 amps. In my opinion they are really good bits of kit and will easily complement a 4kw system especially if you are dual aspect or have strange shading issues!

 

[liquidity]

Unfortunately the recent versions post the serial number mentioned above are clamped at 16 amps or 3600 watts - whichever is LOWER. Strikes me as a very conservative reading of the G83 spec.

 

[screwdriver]

Nothing a firmware upgrade wouldn't fix.........

 

[bazzaqpc]

Hi, I have a Aurora PVI-3.6-OUTD-UK and mine also only goes to 3608 watts, but the real annoyance is that I have mine on two strings one string (A) with 12 panels (3Kw) and one (B) with 4 panels(1Kw).
The 1Kw string regularly hits 1230 watts DC when my irradiance meter registers .97, with string (A) disconnected, the other string 3Kw hits 3390 watts, when string (B) is disconnected, so adding both together it should be possible to achieve 4Kw regularly.
Below is a row from the Aurora data logger with both strings connected Yellow is DC String (A) and Green is DC String (B) red is AC output, sadly I didn’t log grid voltage but this is still useful info.
This shows String (A) generating 2503.04 watts DC and String (B) generating 1255.11 watts DC.

14:23;2;PVI-3.3-OUTD-UK;D;391.1;6.4;2487.7;117.3;10.7;1231.0;3607.4;

With string (B) disconnected this is the results

14:26;2;PVI-3.3-OUTD-UK;D;406.7;8.3;3368.6;0.0;0.0;0.0;3266.4;

The reason I chose this inverter was because the tech spec (http://www.power-one.com/renewable-energy/products/solar/string-inverters/aurora-uno/pvi-30-pvi-36-pvi-42/series) clearly states it will peak at 4000watts (230VAC – 17.2 Amp) well it don’t.
My next step is to see if I can get my money back and replace with SMA 5000TL because I give up with Power One.

 

[Fazzathebrave]

I share your frustration - I have a 3.91 kWp scheme and when the sun is out the output is regularly limited to 3.6kw. This is due to the type of connection, G83, which specifies what generation you can connect to the mains. To get more output than 16A you would need a G59 connection agreement. I understand that these can take some time to obtain and I guess may cost money to get, unlike the G83 which is essentially plug and play from the installers.

I have decided not to pursue it and accept that I am capped when the a) the sun is out and b) when directly overhead. Most of the time I am not capped.

Let us know how you get on if you decide to change your inverter and by definition your connection agreements....

Hi, I have a Aurora PVI-3.6-OUTD-UK and mine also only goes to 3608 watts, but the real annoyance is that I have mine on two strings one string (A) with 12 panels (3Kw) and one (B) with 4 panels(1Kw).
The 1Kw string regularly hits 1230 watts DC when my irradiance meter registers .97, with string (A) disconnected, the other string 3Kw hits 3390 watts, when string (B) is disconnected, so adding both together it should be possible to achieve 4Kw regularly.
Below is a row from the Aurora data logger with both strings connected Yellow is DC String (A) and Green is DC String (B) red is AC output, sadly I didn’t log grid voltage but this is still useful info.
This shows String (A) generating 2503.04 watts DC and String (B) generating 1255.11 watts DC.

14:23;2;PVI-3.3-OUTD-UK;D;391.1;6.4;2487.7;117.3;10.7;1231.0;3607.4;

With string (B) disconnected this is the results

14:26;2;PVI-3.3-OUTD-UK;D;406.7;8.3;3368.6;0.0;0.0;0.0;3266.4;

The reason I chose this inverter was because the tech spec (http://www.power-one.com/renewable-energy/products/solar/string-inverters/aurora-uno/pvi-30-pvi-36-pvi-42/series) clearly states it will peak at 4000watts (230VAC – 17.2 Amp) well it don’t.
My next step is to see if I can get my money back and replace with SMA 5000TL because I give up with Power One.

 

[bazzaqpc]

Hi, Yes just ordred a SMA Sunny Boy 4000TL its still G83, if it don`t get to 4Kw guy said he would change to 5000TL at no extra cost he was so confident 4000TL would be ok.

I,ll let you know.

 

[GaryM]

I'm lead to believe it's how the 4000TL is set-up initially. If you're G83 then it should be set to G83 and be capped to a 16A output, if you're G59 then it's not capped.

 

[bazzaqpc]

Thanks, I`ll check with the guy who is installing it,before i pay out any more dosh.

 

[bazzaqpc]

Yes, you are correct,just had a chat,he thought I was G59 and I`m not so all cancelled and back to squre one !

 

[Earthstore]

Sizing an inverter is quite complex to get it correct, if you have an inverter that is too large, IE a 5000TL on a 4KWP system, of course it should never "max out", however, it takes more power to run a larger inverter also its start up voltage is normally higher, so it may well produce less KWH's per year.

Because the weather is not constant, we do get peak days, and peak times of the day also, therefore if an inverter peaks on the odd occasion, it will probably be working at it's optimum (sweet spot) most of the time, so over a full year producing you more KWH's.

 

[finewine]

Hi Guys, I have a SMA 3600tl-20 and have seen my output peak at 3685w and never higher. ANyway, out of interest I just logged in as an installer on my Sunny Explorer and saw I could change the output from 3680 to 3740w so I did just to see what happens? Well, the inverter turned off and then came back on. Anyway, its not sunny at the moment but do you think I will see the peak output go up to 3740w now or should I change it back?

 

[Earthstore]

Your inverter is set at 3685w to be compliant with the G83 rules, so by changing it you really should have G59 approval from the DNO.
G83 means as it is limited, an installer can fit a system then tell the DNO that it has been installed, over 3680w or 16A you need to have approval from the DNO first, which they may insist on some upgrades.

I do except that it is only a little over, but it is still over, also you may find that it trips out, doubtful, but possible.

I hope this helps.

 

[Rodnay]

I am indeed: Hampshire, 40 deg roof, 10 degrees east of due south.

Happy to wait a bit but the consistent peak value did make me think there was a ceiling somewhere. I've now gone back and looked at the inverter log files and the DC peak wattage from the panels appears to be roughly 3700 watts so perhaps it all makes sense for the time of year.

I have seen the Aurora PVI-3.6-OUTD peak slightly above 3800W on many occasions and different installations you will have losses through your Inverter plus the power ratings of your panels can be slightly higher or less than what they are rated at plus you have losses through your dc cables too. This is with GS83 settings too

 

[Gavin A]

Hi Guys, I have a SMA 3600tl-20 and have seen my output peak at 3685w and never higher. ANyway, out of interest I just logged in as an installer on my Sunny Explorer and saw I could change the output from 3680 to 3740w so I did just to see what happens? Well, the inverter turned off and then came back on. Anyway, its not sunny at the moment but do you think I will see the peak output go up to 3740w now or should I change it back?

this is why we change the installer password. Not that 60 watts is going to make any difference, but we've put our names to the fact that the inverter is limited to 3680W, but it's not really if the customer can just log in and change it themselves.