I assume your top picture is from your solar app? In most cases they measure the current flow from a CT clamp on your meter tail and these aren't very accurate. While it's not impossible that your smart meter is incorrect it's far more likely that your solar app is wrong.

My solar app always reads at least 10% low.

Yeah that’s correct.

I guess that is possible, I also have monitoring of the car charging (16kw to the car) which would leave 14kw for the rest of the house that whole day which we use around 8-12kw a day but that’s not including that we generated 4kw so should be like 8kw so still seemed over what it should be. 
 

The solar fed from CT’s will not be that accurate as mentioned. It also generally doesn’t record continuously but just sample every few minutes. 
On your usage chart, just check that these are smart meter readings and not estimated - that can happen from time to time. 
All electricity meters are calibrated and have to be within tolerance to be in service. 

Just giving an update for anyone that may still see this thread.

2 weeks on and it seems our useage from the Ovo app is pretty unchanged and on somedays even more useage than history. (Started solar from 7th March, some days seem to report correct around 1-5Kw, especailly if we were away for the weekend) but still feels the ‘smart’ meter is not recording only the electricity from the Grid

Feb:
 

March:
 

Report from the Solar app:

As mentioned above some will say this is less accurate, Ovo says for March we have spent 417.46Kw but the solar app is reporting 207.26Kw bought from the grid (just under half of what Ovo says, which is quite a difference and not a minor clamp inefficiency)

Do you have pictures of your meter and clamp positions @Caol ? Your export figure looks high also unless your batteries were full on those days. 
You could also check any detail from the OVO feed for spikes in usage at specific times of day on the ‘high’ consumption days - for example 16th March

Not to hand sadly. The high export days on the 10/11th March seem about right (we were away for the weekend)

For these dates it’s pretty comparable and what I’d expect for the +/- mismatch

Solis: 10th 3.77, 11th 1.88

OVO: 10th 4.11, 11th 1.96

Do you have a feed of usage every 30 mins from your meter? If not it might be worthwhile. I was thinking more in the detail of a particular day of a mismatch and looking at what times the additional usage is occurring 

Yeah we have the 30min reporting form the smart meter enabled to try track whats going on.

Looking on the 13th March

Solis: 4.65 (from grid)

OVO: 11.53

Meanwhile yesterday (20th) look pretty identical so I’m confident its not a clamp issue:

 

Ok that’s useful. There are significant times when your consumption looks more than your generation/self use and the evening peaks are all from the grid rather than solar or battery. You can see the difference between the green line and the orange. 
There’s a lot of detail there so when I get chance I’ll look closer but I’m now wondering if there’s something else amiss like the battery demanding power from the grid if it’s at its lower limit

We do have a EV car but when I plug this in, it seems to match on both. But yeah curious why OVO is reporting quite a considerable difference. People have always said that Smart meters have been charging extra so I don’t know actually know if there’s truth there given the 3rd party monitoring as without it would be hard to dispute against Ovo to say you’re overcharging us and probably have been since we’ve been them (plus however many other customers etc)

All meters are independently validated - they are not OVO’s as such and so have to be calibrated separately. You can do a check if you can turn most things off and just turn on a known load for a certain time, checking meter readings before and afterwards. 
There are some strange looking pieces .. as I said, your export level is a bit high if I compare to others I’ve seen. There’s also an early peak which suggests it’s import to charge the battery which is why I’m wondering if there’s some setting which is making the system charge from the grid more often than usual. 

Yeah I know around 0830-0930 there will be a spike for when we turn the coffee machine on which is often quite accurate.

The graphs also look like we charge the battery from the grid for 5/10mins or so, I was assured this is impossible for the battery to do when it was installed as was 1 thing I had asked. I could try see if this is still the case though

That might help. If you look at 13th, there is a spike around 5am which looks like it’s battery demand (charging from the grid). Generally the batteries have a limit at 10% of their charge when they stop supplying but also if the charge drops below 10% they can ask for a charge from the grid. The level is to stop problems with the batteries and is quite typical. The level is adjustable and so you might want to check what it’s set at. It’s usually called ‘Cut Off’

Yeah agreed. I know batteries generally want to be kept in that 20-80% range (similar to EVs) but was assured the setup is not possible for power to come from the Grid to the battery but yeah will try ask about it :)

Just giving an update for anyone that may still see this thread.

 

2 weeks on and it seems our useage from the Ovo app is pretty unchanged and on somedays even more useage than history. (Started solar from 7th March, some days seem to report correct around 1-5Kw, especailly if we were away for the weekend) but still feels the ‘smart’ meter is not recording only the electricity from the Grid

Feb:
 

March:
 

 

Just looking at this again, bit by bit, while I appreciate that the above detail is not complete, if I add all the March figures together I get 193.13 kWh which is close to the 207 you have from the solar app. Not sure where the 417 kWh comes into it?

Yeah sorry. I added there and got that too. I got the number from the app, I had subtracted March 1-6 away from the total, think total must’ve included Gas Kw usage too