PV+ Grid Voltage Monitor

Merlin139

Today I received a call from my Solar panel installers asking if I was intrested in getting a quote for one of the new Solar PV Batteries and also something called PV+. They claim it can increase PV energy production by upto 20% by cutting out voltage outages!

http://matt-e.co.uk/wp-content/uploads/2014/11/PV-v1-Installation-Manual-v6.pdf

The link shows a PDF which explains what it does. Anybody know anything about them and if so do you think it makes any sense?

I have someone coming to see me tomorrow morning.

Ectophile

It looks like someone's found a new use for the "voltage optimisation" gadgets that have been around for some time.

If your inverter ever shuts down due to over-voltage, it just might help a bit. But the literature says that if your mains voltage ever goes over 253V, then it will shut off anyway. If you never have that problem, then it won't do anything useful at all.

zeupater

Ectophile wrote: »

It looks like someone's found a new use for the "voltage optimisation" gadgets that have been around for some time.

If your inverter ever shuts down due to over-voltage, it just might help a bit. But the literature says that if your mains voltage ever goes over 253V, then it will shut off anyway. If you never have that problem, then it won't do anything useful at all.

Agree .... Looks to me to do nothing other than disconnect if overvoltage conditions exist. The issue is that G83 compliance already covers what happens at the inverter when out of spec voltage or frequency conditions exist ..... Looking at related sales literature there is mention of the unit monitoring the supply voltage and allowing the inverter to 'stay in circuit' longer, however there's absolutely no detail of how it achieves this whilst in no way mentioning that any voltage reduction from the inverter has pretty fundamental export implications ....

We're pretty close to the transformers and therefore towards the top end of the grid voltage specification at various times during the day so would be the ideal target market for the suppliers, yet it's a complete thumbs down from me. I can't see either a benefit or application and therefore wouldn't touch it with a proverbial barge pole ... if we're lucky DaveF will provide a professionally based thumb orientation too ..

HTH
Z

zeupater

Merlin139 wrote: »

... They claim it can increase PV energy production by upto 20% by cutting out voltage outages! ...

Hi

So in reality there's one question to ask yourself in order to justify whether it's worth expending any further effort in researching the device, this being :- How often has your inverter shut down due to grid overvoltage conditions ? ... Even with our relatively high grid voltage, ours has never done so, although it has disconnected and temporarily entered grid condition monitoring mode when low voltage 'out of spec' conditions existed due to supply issues, but that's to be expected ....

HTH
Z

Martyn1981

zeupater wrote: »

Hi
How often has your inverter shut down due to grid overvoltage conditions ? ...

One of mine shut down several times a few years ago. In total I suspect I lost 30 mins. I seem to remember it was a very sunny Sunday afternoon when demand on the grid can be very low.

That probably works out at less than negligible over the 4 years of that system.

@Merlin - if you do, or were to get regular problems with overvoltage, then the DNO has a responsibility to fix the problem. they also have a responsibility for the system to be able to cope with approved SSEGs (small scale electricity generators) so your PV (or the neighbours) is not an acceptable excuse, and the costs fall on the DNO.

Mart.

Merlin139

Thanks for the imput guys.

I will now have questions to put to the salesman this morning.

I spent a good hour trying to find anything I could about it, but it was another language to me.

Will have to see some real proof of any benifit to part with money! Even then not before running it by people here who know what they are talking about.

Dave_Fowler

From what I can see, the only function of the unit is to isolate the solar PV inverter from the grid when the mains voltage rises above 253 volts. From the description of the unit, there is no suggestion that it does any voltage optimisation, but that it is purely a detector circuit which detects the mains voltage followed by a switch which isolates the inverter whenever a higher voltage is detected.

My inverters (Solar Edge and Mastervolt) are rated for a maximum input of 264V and 265V respectively, and there is likely to be a reasonable safety margin above that too. I think it would be highly unlikely that the mains voltage would rise above these figures, and if it does, I think the DNO would be responsible for damage done to residential properties.

In my opinion, the Grid Voltage Monitor would be a waste of money.

Dave F

Merlin139

Thanks Dave.

Merlin139

Salesman turned up this morning and gave me a bit of information regarding the PV+ system and is going to send me a no obligation quote.

He could not show me a picture of it but did say he had one fitted in his house. His was part of a test that the company did in 2014. He has a SolarEdge system and he showed me a graph showing the increase in production of around 20%.

All I saw was a very similar graph to the one I have on my SolarEdge graph on my system.

Then I saw a graph that showed production from the inverter that had big increases and decreases in production during the day. I see this many times on my SolarEdge graphs and had always put this down to clouds coming over but he said its due to the Inverter going into panic mode and shutting down to protect itself then starting up a few seconds later.

The price the company is quoting for customer who's PV they installed is £895 fully fitted. Replaces on of the Red Isolator switches by the inverter. About 10x6x3 inches. New customers will have to pay £1295 fully fitted.

Stated the product has been around years in Europe and is used widely on the continent. He claimed it would increase my production by around 800 kWh.

I would think the obvious test would be to have 2 identical systems on 2 house next to one another without shading and see which performs better. With or without PV+.

He also quoted me for a Tesla Powerwall battery. 7KW storage. Will last for 4200 cycles. ie. fill up then completly discharging. If not totally discharged then it does not count as a cycle.

Said that Tesla quote the price of the battery at £4000.

Also SolarEdge will only allow this battery to be fitted to their system. £4895 fully fitted by my supplier which is Save Heat Energy Renewables Ltd

I have looked on google and can find a price of around $3000 in may of 2015 before Tesla received all the orders for the car so no idea what the price would be now.

Merlin139

Found this on You Tube which shows what it does.

https://www.youtube.com/watch?v=BJ73ZQMU3Xk

zeupater

Hi

Mains here is currently 244.57V whilst we're generating, which isn't unusual for this time of day and as mentioned earlier - we don't have our inverter cutting out due to overvoltage, because it doesn't happen - if it did the inverter would display an event code ..and.. our remote monitor would sound an alarm ..and.. a log entry would be available to see on the remote monitor ..and.. the software used to interrogate the inverter status includes log event history viewing - despite all of this, there are absolutely no overvoltage event entries ...

Anyway, just seen the YouTube demonstration on the link provided and found the contents of the open 'test' unit (if that's the one we're discussing) a little interesting in that voltage manipulation does seem to take place (coil), but it did make me wonder how a manufacturer of devices designed to manipulate AC voltage would technically be able to conduct a test regime where abnormally high voltages would be, let's say, so common that a high metered generation differential (20%) can be demonstrated and a voltage seemingly so predictable to be captured rising during video commentary ... maybe I'm just a cynic ...

HTH
Z