Understanding solar panels

olbas_oil

My daughter has just bought a house with leased solar panels. So she doesn't get any feed-in-tariffs, but she does benefit from the electricity generated, if she uses it. So the first step is to gather some data. The panels are rated at 3.5kW, but are East facing. 
There is an inverter in the roof, and I can see a varying generating figure of about 2kW (clear blue skies just after midday). So I think that means that she could be running a 2kW fire (poor example on the hottest day of the year) without using any electricity from the Grid. 


Down in the garage there is another meter, which I think is called a solar panel meter.


and then the electricity meter (not a smart meter)


1) Electricity generated: I'd like to build up a profile for different times, seasons, weather by recording the Pac from the inverter, but I don't fancy climbing into the attic ten times a day for the next six months. I could fix up a webcam, but there must be an easier way?
2)  I'd like to record figures for electricity consumed from the PV system and from the Grid, when running a washing machine, immersion heater etc. at different times/ weather. How can I see these?
3) What information can be read from the solar power meter?
4) What's the best (UK based) website to explain all this?

Spies

Current clamp around the live from the inverter will give you instantaneous energy, this could then be logged. 

gefnew

A owl meter or onzo will do or an old one supplied by the electric or gas companies.
OWL Wireless Energy Monitor Boxed with Sensor Remote Monitor & Sender Box - W77 | eBay

Reed_Richards

My solar panels were installed with two meters, one which records electricity generation and one which shows instantaneous power.  It's worth searching around for the latter before you invest in extra equipment.  

1961Nick

This monitor from GEO will provide real time monitoring of any meter with a pulsing led.

https://geotogether.com/product/hub-led-sensor/

Martyn1981

For a rough profile you can go to PVGIS and enter the basic info, location, KWp size, orientation, and roof pitch. This will give you a really good guesstimate of average generation for the year and each month.

Of course, PV at any time, and any day, can vary massively from 0% to 200% of the daily average. In the summer I typically get about 50% to 150% of what I expect per day, and in the winter 0-200%.

My monthly gen is typically around 80-120% of PVGIS estimate. Worst ever, and real standouts, were Nov and Dec 2015 with 59% and 55% respectively. Best ever, May 2020 135%.

paul991

a shelly clamp on each live  tail or  any where  you want so  can  monitor  production
usage and import export

olbas_oil

Martyn1981 said:

For a rough profile you can go to PVGIS and enter the basic info, location, KWp size, orientation, and roof pitch. This will give you a really good guesstimate of average generation for the year and each month.

Thank you, that looks like a really useful site. But I am confused by KWp. Is that the same as the 3.51kW Declared Net Capacity on my MCS certificate?

Martyn1981

olbas_oil said:

Martyn1981 said:

For a rough profile you can go to PVGIS and enter the basic info, location, KWp size, orientation, and roof pitch. This will give you a really good guesstimate of average generation for the year and each month.

Thank you, that looks like a really useful site. But I am confused by KWp. Is that the same as the 3.51kW Declared Net Capacity on my MCS certificate?

Hiya. For simplicity I want to say yes, and it probably is, just covering my back in case there is some weird issue with the MCS certificate. To double check, does it say what the rating of the panels is, for instance, are there 14 250Wp panels, which would total 3.5kWp? [Maybe 13 x 270Wp panels to give 3.51kWp?]

Don't worry about the 'p' (for peak), that's just because PV panels are rated at 25degree Celsius, but will generate less if hotter (and more if colder).

QrizB

olbas_oil said:

My daughter has just bought a house with leased solar panels.

Just an aside, but did that go OK? Did she have any problems with the conveyancing / mortgage etc?

I ask because we get a few posts about people wanting to buy out their solar leases to make selling their properties easier, and I think this is the first I've seen where someone has bought a property but kept the lease.

olbas_oil

QrizB said:

olbas_oil said:

My daughter has just bought a house with leased solar panels.

Just an aside, but did that go OK? Did she have any problems with the conveyancing / mortgage etc?

I ask because we get a few posts about people wanting to buy out their solar leases to make selling their properties easier, and I think this is the first I've seen where someone has bought a property but kept the lease.

It did not go well...

The current panel owners did not respond to me at all when I made initial enquiries in December, nor again in May. Emails and phone calls were simply ignored. I had thought that was because I had no formal relationship with them, but in fact the vendor's solicitor also met with no response when asking for the MCS certificate. I think they are a large investment company that collect the FIT payments but don't bother otherwise.

The MCS certificate was required by our lender, and it looked as though the house was going to be unmortgageable. That lasted at least a couple of months, with their solicitor trying multiple times. I'm not sure how they actually got through in the end, but even the agent was pessimistic that it would happen.

On the positive side I was able to trace other houses that had sold recently with solar panels owned by the same company. They confirmed that the company was difficult to reach, but there had been no need to make contact. All readings etc are done remotely. If there is ever a need to do roof repairs, we will have an issue with giving notification, but we'll cross that bridge when/if we come to it.

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