PV+ Scam?

Rackabello

Martyn1981 wrote: »

Hiya, and thanks for posting that, clearly looks like a scam given the mark up, and TBH probably not worth having the kit anyway.

Inverters (most of them) should shut down if the grid voltage hits 253V (you say the inverter was showing 246V, so it's a bit high there, but it does vary across the country and also depending on the day and time etc.). the shutdown is for safety reasons to prevent PV pushing the grid voltage even higher as it should be operating at between 216 and 253V.

I've only noticed one of my inverters shutting down about 3 or 4 years back when the voltage hit 253V (Sunday afternoon, when demand is low). It restarted about 10mins later when the grid voltage had dropped back down.

It may have happened more, but certainly not anything that is impacting annual generation here, and typically grid voltage is in the high 230's.

Perhaps the 468 he noted was the DC side voltage suggesting approx 16 panels (if they are 30V each and on a single string). What does that mean ..... nothing, just the PV system doing what the PV system does, taking in DC leccy at a certain voltage and amperage, then changing it to AC at a grid similar voltage.

Lastly, another check you could do is look at section 5 of the PV FAQ's (see my autosig) and see what the annual PV generation guesstimate for your Nan's system is, then divide the total figure from the TGM (total generation meter) by the number of years the system has been operational, and see if the numbers are similar.

Please come back and chat/check all the numbers as it would be useful to see how all of this, and my speculation(s) fit together.

Hey,


I've finally managed to get the information from her about generation and the panels. There are 16 panels, and it's a 4kWp system, says test voltage is 250, and angle is 46. I'm pretty sure the panels are south facing. According to the generation calculator she should get 4240kW, but according to the meter reads (from paper statements) she generated 3291 between 19 August 2016, and 30 August 2017.


What would your thoughts on this be?


Thanks

Rackabello

Fl4sh wrote: »

I too had a call.from.these and an engineer turned uo today. I too.was told they had taken over the customer database from my supplier who went bust. Promised.to.sort out any problems i had with system....yeah right...went onto loft twiddled with inverter and came back with photo of readings also totalling over 400..280 on one set of panels and 188 on other..said they should both read 240 volts and so i needed a pv+ optimiser. Sent him.packing as wanted £2995 for the priviledge!!.
With a bit of research it seems that each oanel generates approx 30v of dc power..i have 16 panels.so thats approx 460..this then gets inverted to 240v ac so he was blagging me. To further allay my suspicions i spoke to afore who manufacture the inverters and he confirmed that they are aware of this scam
Don't fall.for.it!!!

Wow, sounds like the exact situation we had. I'm glad they left without your money! Interesting that the manufacturers seem aware of this scam, I feel like they should be getting that information to their customers if they know it's happening.

Martyn1981

Rackabello wrote: »

Hey,


I've finally managed to get the information from her about generation and the panels. There are 16 panels, and it's a 4kWp system, says test voltage is 250, and angle is 46. I'm pretty sure the panels are south facing. According to the generation calculator she should get 4240kW, but according to the meter reads (from paper statements) she generated 3291 between 19 August 2016, and 30 August 2017.


What would your thoughts on this be?


Thanks

Hiya. My first thought is that 3,291kWh sounds a bit low, but it will depend on exact pitch, orientation and shading. If south facing and no shade, then closer to 4,000kWh would be my gut reaction.

Have a look at the PV FAQs section 5 and get a guesstimate of generation from PVGIS.

The 250V figure also sounds right to me, assuming 16 standard panels, then they are most likely about 30V each, so 16x30V = 480V. Next I'll assume the 16 panels are in two strings of 8, which will halve the voltage (and double the amperage) so if that's 250V DC, then most likely fine.

If however it's 250V AC, then again suggests grid voltage is high and close to the 253V that will cause the inverter to shutdown. If grid voltage is high and normally high, then it's the DNO's responsibility to sort out the issue, even if there are SSEG's (small scale electricity generators (PV etc)) on the line. The inverter might display all of this info, depending on type, so it can be checked, perhaps with some tentative button presses?

Rackabello

Martyn1981 wrote: »

Hiya. My first thought is that 3,291kWh sounds a bit low, but it will depend on exact pitch, orientation and shading. If south facing and no shade, then closer to 4,000kWh would be my gut reaction.

Have a look at the PV FAQs section 5 and get a guesstimate of generation from PVGIS.

The 250V figure also sounds right to me, assuming 16 standard panels, then they are most likely about 30V each, so 16x30V = 480V. Next I'll assume the 16 panels are in two strings of 8, which will halve the voltage (and double the amperage) so if that's 250V DC, then most likely fine.

If however it's 250V AC, then again suggests grid voltage is high and close to the 253V that will cause the inverter to shutdown. If grid voltage is high and normally high, then it's the DNO's responsibility to sort out the issue, even if there are SSEG's (small scale electricity generators (PV etc)) on the line. The inverter might display all of this info, depending on type, so it can be checked, perhaps with some tentative button presses?

I've had a look at that generation calculator you link and it came up with 4230, but I didn't see anywhere to input shade factor. But it does seem a lot higher than what we're getting.



Oh, and I think I may have misred the documents. 250 is the test voltage. The V in array perameters is 600, and under string test is 490, and A is 2.1, if any of that means something to you. I'll see if I can get someone to check the actual current voltage again, but that won't be till tomorrow now.

I'm also a bit confused, as there seem to be two lots of surveys for the solar panels. The first estimates the output (using SEM) at 3820, and the second at 2297. Both say 5 degrees from south, and the first (higher estimate) says a shade factor of 1, and inclination of 47 degrees. The second has a shade factor of 0.6, and inclination of 46.



With regards to it being the DNO's responsability, how would we go about getting it resolved, if it is consistantly that high?

Martyn1981

Rackabello wrote: »

I've had a look at that generation calculator you link and it came up with 4230, but I didn't see anywhere to input shade factor. But it does seem a lot higher than what we're getting.



Oh, and I think I may have misred the documents. 250 is the test voltage. The V in array perameters is 600, and under string test is 490, and A is 2.1, if any of that means something to you. I'll see if I can get someone to check the actual current voltage again, but that won't be till tomorrow now.

I'm also a bit confused, as there seem to be two lots of surveys for the solar panels. The first estimates the output (using SEM) at 3820, and the second at 2297. Both say 5 degrees from south, and the first (higher estimate) says a shade factor of 1, and inclination of 47 degrees. The second has a shade factor of 0.6, and inclination of 46.



With regards to it being the DNO's responsability, how would we go about getting it resolved, if it is consistantly that high?

Obviously I'm making lots of guesses here, but is there a fair bit of shade? That will affect generation. Also I'm not an electrician, but that string test figure of 490V jumps out at me, I might be completely wrong, but could mean that all 16 panels are on one string, which means all panels will be impacted by shade on any one (or more) panels.

Sorry to make guesses, but hopefully you can see why 490V might be significant as most panels are around 30V each.

Can you note the inverter make and model and post on here, that way we can have a look at the specs and see if that gives more info.

Regarding the grid voltage, first, don't rush to conclusions just coz some bod on the internet had an idea, I might be completely wrong. So, see if the inverter displays the grid voltage and if so, just see over time what it says. Mine has hit 253V, but is generally in the high 230's to low 240's. You could also get a plug in power monitor that are useful for seeing how much energy items consume, like the telly, fridge etc, as these will also tell you the current grid voltage, mine was about £10 from Maplins (so bit too late for them), but they are widely available (I think).

What's your initial feelings about shade, are there houses nearby that block the sun part of the day, trees, chimney etc?

Edit - Sorry, forgot - the DNO's (10 of em I think) are responsible for the local grid. You should be able to get the name from local advice sources, such as energy bills etc as they are the ones to report powercuts too. You can just ring them and report that the voltage is high, but ...... before you do that, and they try to get rid of you quick, make sure it is high, and consistently high. Although the UK is technically a 230V country now, voltage is more like the old 240V, so they won't be interested in anything under 250V (I suspect), and even then will want you to argue that it happens a lot. If they accept there's an issue, then they will probably want to monitor it for a week or so to see, and if lucky can make some minor local alterations to address it.

Rackabello

Martyn1981 wrote: »

Obviously I'm making lots of guesses here, but is there a fair bit of shade? That will affect generation. Also I'm not an electrician, but that string test figure of 490V jumps out at me, I might be completely wrong, but could mean that all 16 panels are on one string, which means all panels will be impacted by shade on any one (or more) panels.

Sorry to make guesses, but hopefully you can see why 490V might be significant as most panels are around 30V each.

Can you note the inverter make and model and post on here, that way we can have a look at the specs and see if that gives more info.

Regarding the grid voltage, first, don't rush to conclusions just coz some bod on the internet had an idea, I might be completely wrong. So, see if the inverter displays the grid voltage and if so, just see over time what it says. Mine has hit 253V, but is generally in the high 230's to low 240's. You could also get a plug in power monitor that are useful for seeing how much energy items consume, like the telly, fridge etc, as these will also tell you the current grid voltage, mine was about £10 from Maplins (so bit too late for them), but they are widely available (I think).

What's your initial feelings about shade, are there houses nearby that block the sun part of the day, trees, chimney etc?

Edit - Sorry, forgot - the DNO's (10 of em I think) are responsible for the local grid. You should be able to get the name from local advice sources, such as energy bills etc as they are the ones to report powercuts too. You can just ring them and report that the voltage is high, but ...... before you do that, and they try to get rid of you quick, make sure it is high, and consistently high. Although the UK is technically a 230V country now, voltage is more like the old 240V, so they won't be interested in anything under 250V (I suspect), and even then will want you to argue that it happens a lot. If they accept there's an issue, then they will probably want to monitor it for a week or so to see, and if lucky can make some minor local alterations to address it.

Shade wise there is a house the same height, with chimney around 6ft or so away on the side of the panels, so there could be a fair amount of shade. Especially if you think that any shade would affect all of the panels. The chimney on her house is on the north side of the panels so shouldn't cause any problems.



The inverter is a Fronius IG TL. I had someone take a look at it and get some readings today. Weren't able to find anything like an average AC voltage, but got a few other readings. The max AC voltage was 255.8, and max PV array output was 579.
At the time (coming up to 2pm) the AC output was 395-421, and the max AC voltage today was 249.8.



From my understanding that all does look on the high side, but due to potential shade problems it might be that the panels aren't really underperforming. What would be your thoughts?


I do have one of those plugs to monitor power useage. Can't remember if it shows grid voltage, but I'll see if I can pull it out and we can give it a test, though that probably wouldn't be until the weekend. Thanks for all this info though, we'll keep an eye on voltage and hopefully get something sorted about it if it's causing problems.

Martyn1981

Rackabello wrote: »

The inverter is a Fronius IG TL. I had someone take a look at it and get some readings today. Weren't able to find anything like an average AC voltage, but got a few other readings. The max AC voltage was 255.8, and max PV array output was 579.
At the time (coming up to 2pm) the AC output was 395-421, and the max AC voltage today was 249.8.

From my understanding that all does look on the high side, but due to potential shade problems it might be that the panels aren't really underperforming. What would be your thoughts?

I do have one of those plugs to monitor power useage. Can't remember if it shows grid voltage, but I'll see if I can pull it out and we can give it a test, though that probably wouldn't be until the weekend. Thanks for all this info though, we'll keep an eye on voltage and hopefully get something sorted about it if it's causing problems.

Hi again, and thanks, I think that helps, but again I apologise for guessing a bit here.

So, the AC high shows it has gone over 253V, so that might shutdown the inverter if it is set up with the latest UK regs, but that will depend on when it was installed. The inverter will then keep checking grid voltage and switch back on when below 253V.

The AC at time of checking of 250V suggests that the property is at the high end, but of course we need to be careful that it wasn't just a freak coincidence, so keep checking if you can. If it is consistently around 250V or more then you should contact the DNO and see what they can do.

I've had a look for the inverter specs, I think I've found them [URL="file:///C:/Users/Martyn/Downloads/42,0426,0074,EA%20(1).pdf"]here from page 128 onwards[/URL], I'll assume it's the 3.6kW model.

Now ...... I'm speculating here, but I can't see 'the usual' line that states how many inputs, and how many MPPT inputs the inverter can take, so I'm assuming it can only take a single string. Also I note that the MPP voltage 350-700V, which again suggests to me that these inverters are designed for a single string as two strings would mean that voltage would be around 250V, so too low.

Again, sorry for guessing so much, but I'd conclude that the system is a single string install (nothing wrong with that) but it does mean that any shade on a panel or two, will impact all 16 panels. If it had two strings and say two panels that get shade in the morning, and two others that get shade in the afternoon, then you'd split the system into two strings of 8, so only 8 are impacted in the morning, and the other 8 in the afternoon - in order to minimise shade impacts - does that make any sense?

So, some shading might be worse than it would at first appear. Retrospective changes can be made, but they'd be costly, and I'd think the decision is borderline as it's performing around 75%.

Hopefully someone with a better understanding of the leccy side of all this can help, and advise if they think I'm reading the inverter specs correctly and making the right assumptions?