Ampy 5235a Electricity Meter

[JonCottPV]

Hmm.
I am very much obliged for your responses.
It seems to be something that is within my ability to understand.
But I am completely flummoxed by this apparent zero export.

Does it change everything if I mention that a Tesla Powerwall was installed at the same time?
And I charge my EV about 4days out of 7? Its only a Citroen c-zero so no big demands.

Cheers
Jon

 

[JohnW2]

... But I am completely flummoxed by this apparent zero export.

As you have been told. it's possible that there is no export. That could be simply because you are using all of the PV-generated electricity yourself but, as you've also been told, it's also possible that your house's connection to the network is such that no export would ever be possible. However, the daft way this FIT business works, you get paid for 'exporting' (at someone else's cost), even when export is not possible!

As also explained, the other possibility is that the 'check meter' you have has not been programmed to actually record export as well as import.

Kind Regards, John

 

[Lectrician]

If you’re charging a battery I reckon there is every likelyhood of ZERO export. That’s the point of them!

 

[JohnW2]

If you’re charging a battery I reckon there is every likelyhood of ZERO export. That’s the point of them!

Don't most people charge EVs at night, when there's 'unlikely' to be any solar power generated that could be exported, even if the charging wasn't happening?

Kind Regards, John

 

[ban-all-sheds]

Does it change everything if I mention that a Tesla Powerwall was installed at the same time?

Durrr...

Of course it does. FGS.

The current generation of Powerwall is a 13.5kWh module, and the whole point of it is to store as much of the energy produced by your PV system as possible.

If you are storing the output from your panels you can't also be exporting it.

November generation was 52kWh, December 24kWh and Jan 35kWh.

If we assume the same amount per day each month that's 1.73/0.77/1.13 kWh/day.

i.e. 12.8%/5.7%/8.4% of the battery capacity.

Now we have no idea what your usage is, but should anybody be surprised if it's more than a few kWh/day, and therefore everything your PV panels generates gets used by you?

No.

We've had days of back-and-forth because you just can't think.

FGS.

 

[Lectrician]

Don't most people charge EVs at night, when there's 'unlikely' to be any solar power generated that could be exported, even if the charging wasn't happening?

Kind Regards, John

Not the car battery, the Tesla.

 

[ban-all-sheds]

The other thing you can do with a Powerwall is to charge it from the grid at cheap rate overnight, and thus be able to use cheap-rate electricity during the day.

 

[JohnW2]

Not the car battery, the Tesla.

Indeed. It was only when BAS clarified that I realised what the Tesla was doing. I guess I was not far off when I wrote ...

As you have been told. it's possible that there is no export. That could be simply because you are using all of the PV-generated electricity yourself ....

!

Kind Regards, John

 

[Lectrician]

Typical half story.

 

[JohnW2]

Typical half story.

Indeed, but I wouldn't criticise the OP too much, since he clearly didn't realise the relevance of having the Tesla installed, and quite probably did not realise exactly what it was doing.

Kind Regards, John

 

[ban-all-sheds]

You mean he spent £7K-ish on something when he didn't know what it did?

How bizarre.

 

[ban-all-sheds]

Are you suggesting that if he had sat down, and thought through the fact that his panels generate electricity which he can sell when he isn't using it, and that he has installed a battery which will store the electricity when he isn't using it, he wouldn't have realised that if he is storing it he couldn't also be selling it?

 

[JonCottPV]

Thanks guys for all shades of helpful responses.

I'll leave it there.

BTW The original issue was the 70% increase in electric bill when doubling pv generation.

Cheers

 

[JohnW2]

BTW The original issue was the 70% increase in electric bill when doubling pv generation.

I understand that. Did you start the EV charging at the same time as you had the Powerwall installed? If not, how/when were you previously charging it - were you perhaps using cheap night-time electricity (with something like an E7 tariff)?

Kind Regards, John

 

[JonCottPV]

Thanks John for asking.
We've had the EV since Oct 2013. Bought secondhand. Charging off a commando-type socket installed by the pv supplier.
We moved in April 2014 and had a chargemaster/polar chargepoint installed.
We dont have economy 7 though we have toyed with the idea. We work part-time from home. So it might end up costing a lot more for our daytime activity. About 8000 EV miles a year since then. All from home charge.
The Powerwall was intended to charge from pv and discharge for our general consumption including EV charging. Obviously not much in the winter months. It is also showing unexpected signs of poor efficiency ie about 20% loss between charge and discharge.

Cheers