PV+ - anybody heard of this?

[oldsalty]

Guys, don't get sidetracked into the same old VO conversations - I think we all know our opinions on those (at least in a domestic environment anyway), this PV+ unit is pitched as something different....I for one would like to know exactly how this is supposed to differ from VO and how it's compliant to be installed between the SSEG and the grid....I've already decided on its actual value

VMT for all your input guys. Guess I will be leaving my GBP895 in the bank then?

 

[Gavin A]

I am still not convinced Gavin, because although I take your point that certain combinations of generated power, kettle power and voltage could work as you describe, most times when voltage is high will be bright sunshine with good output from the panels that has a good chance of covering the kettle.

I'm not arguing it's a major impact, just that there is some truth to it.

 

[matthunt]

Hi Guys, sorry not been on in a while as been rather busy! what question do you require answering about the PV+ unit first?

 

[SibertSolar]

Ok, I'll throw a question in - is the PV+ unit wired between the grid and the inverter's AC output?


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[matthunt]

Ok, I'll throw a question in - is the PV+ unit wired between the grid and the inverter's AC output?


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Yes the PV + is connected between the grid and the inverter, but not between the meter and the inverter

 

[SibertSolar]

Ok, thanks, and is the unit manipulating the voltage/supply that the inverter senses and synchronises with? Also, how is the PV+ unit different from a VO unit?


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[marc8]

PV+ not sure if it will be cost effective

 

[Gavin A]

Yes the PV + is connected between the grid and the inverter, but not between the meter and the inverter

to be clear, is the inverter backfeeding through the VO transformer?

IT looks like it may not be, and is simply taking the place of a henley block / distro board to make for a neater installation, with the VO unit only operating on the supply (from combined solar and grid) to the house consumer unit rather than the actual PV circuit itself.

Hopefully that's the case otherwise it would invalidate the G83 or G59 protection settings on the inverter which are designed to protect the local grid from over voltage caused (at least in part) by the PV generation.

 

[matthunt]

Gentlemen, the best way to look at the product is like a G59 relay, if the grid reaches statutory limits then the device will switch the inverter out of circuit but on the grid side and not the inverter side.

 

[Gavin A]

Gentlemen, the best way to look at the product is like a G59 relay, if the grid reaches statutory limits then the device will switch the inverter out of circuit but on the grid side and not the inverter side.

have you got G83 type test approval for that? There's no mention of it on your website.

Also can you explain what the point is in doing that rather than simply feeding the inverter in on the grid side of the VO unit? I suppose you save the transformer losses for self consumption, but then the voltage at the house side will be higher than if the PV was connected to the other side due to the resistance in the transformer (when the house is exporting).

The manual and wiring diagram don't really make it look like it works in that way.

To satisfy my curiosity would you mind just confirming directly that the PV is backfeeding through the VO unit to export to the grid?

If you actually have managed to produce a decent unit that serves a proper purpose and integrates well with PV without invalidating the G83 type test approvals, then it could be worth us having a look at. I gave up on Vo a few years ago due to the level of unsupported rubbish being spouted about it, and rubbish build quality and support from the units we tried.

 

[GreenE4u]

Hello Gentlemen, This is my first time on this forum so apologies if I over step the mark. As Matthunt pointed out " look at the product is like a G59 relay, if the grid reaches statutory limits then the device will switch the inverter out of circuit" The important words are "if the grid reaches statutory limits."

Given that the Solar panel system has to comply with the strict requirements of the grid, how can such a relay improve the performance of the solar panel system? Where does the 25% increase in performance all these companies selling the device come from? Is there any hard facts?

Having had a 4kW system in operation for 7yrs and taken readings of the performance of the panels and system over the period, I fail to see the benefits of adding such a device. As such I think it is a waist of money.

 

[Bruce076]

I have heard of this (unfortunately).

I discovered some unscrupulous salesman had sold one of these DC PV+ units to my elderly mother, ripping her off to the tune of £2,500. After 6 months her FiT readings were slightly lower than the same period the previous year. I simply put this down to the panels maybe needing a clean. Before installation she was told by the salesman her FiT readings would double!

I'm personally seeing that the firm involved is reported to Trading Standards for this disgusting example of gross miss-selling.

My advice would be avoid at all cost in a domestic situation.

 

[Rob Latta]

I saw one of these last week from a family member. £3000 if the offer was taken up now, because they were in the area doing other installs and VAT is currently cheaper. £4000 if taken up later because VAT will go up after April to 20% on solar things

This was their sales pitch

• Our inverter is close to end of warranty (5 years). All the time it's being subjected to spikes in voltage which cause stress and it has to give off those spikes as wasted heat.
• They will install a "power saver" which will reduce or eliminate the spikes, thus protecting the inverter from all that stress that's lowering it's life expectancy
  
• Something about our voltage being over 250V but the power saver will also cause our voltage to drop to 220V which will save money on appliances
• They will provide a 10 year guarantee for it and for our existing inverter. Replacement would be with a high quality inverter. I asked what the current cost of such an inverter would be today and they said £2500
  
• The power saver will make more electricity go back into the grid and increase the revenue from the feed in tarriff by 40% (£300 per year)
• It will make more electricity available for our appliances and decrease our electricity use by 30% (£200 per year)

After listening to the pitch my family member tried to buy it. If I hadn't suggested we get the advice of a relative in the energy business they would have bought it.

Some web research leads me to conclude they were selling what's known as PV+ which is approximately £700-£1000 fully installed (although that would be without the inverter warranty extension mentioned above) according to random websites I see selling it and a posting on the Money Saving experts forums (I tried to link them but it wouldn't allow me to)

 

[Clodbuster]

Rob Latta,
I had a very similar sales pitch yesterday and, blow me down, I could get a discount as they had installers in the area.

I listened to the salesman who tells me that all panel arrays have a protection so if one panel goes over the rating for that panel (in my case 240w) then the inverter shuts down THE WHOLE array for 15 minutes so I lose all generation for that period. This may happen 4 - 5 times per day. This “PV Plus” irons these spikes out preventing the inverter shutting down so you record greater generation. He said between a minimum of 25% to a possible 40% depending on season etc.

Cost is £4000, at my current generation and return about 7.5 years to recoup.

Anyone able to corroborate that the panels are shut down so frequently?

 

[LeeH]

Sounds like snake oil to me.

Never seen mine shut down, you can see the generation on a graph online.