Understanding Solar Panel Meter Readings

[thekingstyle]

Hi all,

We bough new build house with 4 solar panels which are not plugged to the grid. We are wondering how to understand the readings which are on it. For example currently it shows 08.3 kWh unit.
What would that be in Watts? All the calculators ask me to put kWh and time which is confusing since I only have the reading

 

[JohnD]

Watts are volts multiplied by amps

If you are in UK, the Actual* voltage will be about 240v

So 8.3kW (which is 8300 Watts)

Divided by 240 Volts

Is about 34 Amps







*for reasons we need not go into, nominal voltage is 230v

 

[JohnD]

A kWh is a kilowatt-hour. One kilowatt, delivered for one hour.

Or two kw delivered for half an hour

Or 10kw delivered for 6 minutes

Your electricity meter and your bill show kWh.

You either have, or need, a kWh display.

My solar inverter has a button that cycles the display through kW currently being generated, and kWh generated since installation, and some other things.

If yours is not connected to the grid, what happens to the electricty it generates?

 

[thekingstyle]

I'm still confused, sorry.
So out of the reading I'm getting (as attached) there is no way of telling what is the current wattage coming in from solar? Eg. If I can run a 1000w kettle of it etc ?

@JohnD
Everything panels generate either get used or it gets wasted (that's how developer explained it: used it or lose it).

 

[JohnD]

You have not shown the whole of that meter. It might have a button on it. I can see it says "Import" and "export."

There is probably a control panel and display on your inverter.

If yours is not connected to the grid, what happens to the electricity it generates?

?

 

[thekingstyle]

John there is nothing on the right of the meter apart from serial number. and I replied to your question above but it any excess gets wasted if not used

 

[oceansoul]

Generally solar systems will not generate at all unless they can synchronize with the grid. This is to stop them working in a power cut and back feeding the grid. Unless you have a small scale DC battery system (the kind you would have in a camper van etc) then it is probably connected to the grid.
If you attach a photo of the solar connection, inverter and DNO cutout/meter we might be able to assist further.

 

[thekingstyle]

Well, it's definitely not plugged to the grid and it's definitely generating electricity as on a normal bright day my smart meter shows I'm using nothing. I'll have two pcs and two monitors running at that time and few other little things. Obviously when I use more electricity then the panels are supplying it shows what I'm using, but generally it's 0 in day time. I'm wondering how many watts it generates on a typical day.

 

[Why Not Indeed]

Well, it's definitely not plugged to the grid and it's definitely generating electricity as on a normal bright day my smart meter shows I'm using nothing

I think there's some talking at cross purposes here. "connected to the grid" in this context doesn't literally mean on its own export meter, completely separate to your import meter [although it could mean that, you wouldn't have any way of using it locally]. If the inverter output is connected downstream of your import meter, then it is eventually connected to the grid. The inverter will do nothing without a mains "signal" to follow. The behaviour you've described is consistent with that.

get used or it gets wasted

You don't have an export tariff; ie, all the power generated locally beyond what you can use, you are giving to the grid for free and not being compensated for.

All the calculators ask me to put kWh and time which is confusing since I only have the reading

You can only see a cumulative reading on your meter. Record a reading, wait a period of time, record another. Et voila, you have both.

How many meters do you have in total? 8kWh seems a bit low, unless you literally just switched it on this week?

Rayleigh Instruments RIHXE12R MID Certified Single Phase 100A Solar Generation Meter With Pulse Output With Import and Export

<p><span class="rcRedSubHead">This product is no longer available</span></p> RIHXE12R is a compact MID Certified single phase two wire solar generation meter. The cost-efficient design and offers an excellent price-performance ratio.</br> </br> RIHXE1

www.rayleigh.com

"The meter has two registers
000 is the Import Reading - which is what is being generated by the inverter.
010 is the Export Reading - which is what is coming back from the grid

The meter will autoscroll between the 2 readings every 15 seconds."

 

[thekingstyle]

I think there's some talking at cross purposes here. "connected to the grid" in this context doesn't literally mean on its own export meter, completely separate to your import meter [although it could mean that, you wouldn't have any way of using it locally]. If the inverter output is connected downstream of your import meter, then it is eventually connected to the grid. The inverter will do nothing without a mains "signal" to follow. The behaviour you've described is consistent with that.


You don't have an export tariff; ie, all the power generated locally beyond what you can use, you are giving to the grid for free and not being compensated for.


You can only see a cumulative reading on your meter. Record a reading, wait a period of time, record another. Et voila, you have both.

How many meters do you have in total? 8kWh seems a bit low, unless you literally just switched it on this week?

Rayleigh Instruments RIHXE12R MID Certified Single Phase 100A Solar Generation Meter With Pulse Output With Import and Export

<p><span class="rcRedSubHead">This product is no longer available</span></p> RIHXE12R is a compact MID Certified single phase two wire solar generation meter. The cost-efficient design and offers an excellent price-performance ratio.</br> </br> RIHXE1

www.rayleigh.com

"The meter has two registers
000 is the Import Reading - which is what is being generated by the inverter.
010 is the Export Reading - which is what is coming back from the grid

The meter will autoscroll between the 2 readings every 15 seconds."

Hi ,


Thank you for such a lengthy reply. It makes a lot more sense now, however I still don't 100% get it

I was told by developer that I'm not connected to the grid, but I cant really verify that. If I was and Im giving all the energy for free due to not having a tariff could I possibly change that?

What you mean by how many meters do i have? There is only one meter and I have 4 panels. It is switched on all the time, however the reading was taken around 3:30 and there was not much sun at that time. What should it be?

So if I take a reading and then in one hour take another and then average it and use the calculator it will show how many watts it generates? Or should I go in the loft and check what the inverter is displaying assuming it has a display lol.


As for the meter you are exactly right. I have the export figure too as per attached. (Both taken as the same time)

 

[JohnD]

Everything panels generate either get used or it gets wasted (that's how developer explained it: used it or lose it).

This is almost certainly wrong. It goes to the grid.

 

[StephenStephen]

Do you have a display on the inverter itself? If so, this could almost certainly show you the current output in kW of the solar.

Do you have an electricity supplier?
Your solar is connected to the grid unless
your electricity system is not connected to the grid (ie; if you don't have an electricity supplier).

It sounds as though your excess generation goes to the grid, but you don't get paid for it. If you want to get paid for it, you might need the installation to have been MSC certified, which, from what you've said, I suspect it is not - check with the developer.

Do you have a smart meter? That would tell you how much excess generation you have at any one time (though I don't always find mine dependable).

To be honest, I wouldn't think 4 solar panels would generate enough excess to be bothered getting paid for.
It would make sense to shift your electricity usage to sunny times.

 

[bernardgreen]

A solar panel in sunlight is like a battery, it would supply power if a load was connected to it, With no load connected the panel would have a voltage but with no current flowing it would not be producing any power,

When there is no sunlight the panel is like a flat battery

The load could be ( and often is ) an invertor converting the DC from the panel into AC at 230 Volts for the house.

The invertor and the load(s) it is supplying with 230 Volts AC determine how much current ( and hence how much power ) is taken from the panel,

If there is a grid connection then the amount of surplus ( not required by the house ) power fed to the grid would ( or should be ) be set by the invertor to be that which uses up all the power the panel can supply that moment in time. That will depend how bright or dim the sunlight is,

 

[Why Not Indeed]

If your export figure hasn't increased in 24h and that's your only meter then either:

- Instantaneous generation hasn't exceeded consumption in the last 24h
- Inverter is switched off

We still don't know how long you've had these panels or what size they are, so can't really say if 8kWh of export is a big number or not.
To find out what you can get paid, google "smart export guarantee" and see what tariffs are on offer. Be prepared to be disappointed.

 

[Why Not Indeed]

This is almost certainly wrong. It goes to the grid.

If it goes to the grid and the OP gets nothing for it, then from his POV, it's wasted.