Solar and Powerwall just installed - some issues - anyone had something similar?

diveleader

On Monday my Powerwall 2 (with non backup gateway) and 5.5kWp solar was fitted.
That evening it all worked as expected.
The following morning was also fine, but I encountered issues circa 11am, when the PW was fully charged.
At this time, the solar output (measured by the Tesla App and Gateway) started to read approx 100% higher than it should. ie reading 8kW. The inverter read correctly (4.4-4.8kW). The app also did not detect any house loads under 2kW.
The CT clamps are in the correct place and facing the right way.
I stopped the PW and restarted and all was working fine again.
I also informed the installer of the issue.
Yesterday, the unit worked fine with no problems at all.
This morning, with the PW battery @ 74%, it registered as being on standby (ie not charging). More weirdly, as the Solar output grew, this was being 
reflected 100% in the home usage. For example, 1.1kW of generation and 1.1 of home usage!
Increasing load in the house does not alter the home usage at all!!
The PW is not charging, and does not contribute to load in the house (If I increase home load to that greater than solar generations, then the deficit comes from the grid)
I have spoken to the installer and they suspect a faulty gateway and have logged a request with Tesla to investigate.
Attached pic shows PV and home usage overlaying each other exactly, as the solar day progresses. And Tuesday's spikes in PV generation (system is 5.5kwp)

Anyone had a similar issue?
Any idea how long Tesla take to look into this?

Looks like I'll be using my bedroom AC from the grid tonight.

Petriix

Are you *sure* that the CT clamps are correctly installed? Could they have been plugged into the wrong sockets on the controller? It looks like your house usage is being added to what it thinks the generation is. 

JKenH

I had a similar issue when my solar and battery (not Powerwall) were first installed. The installer came back and moved the clamps and all was well.

diveleader

Thanks for the comments. The installation electrician is coming round tomorrow AM - so we will see whats amiss (hopefully)  

diveleader

Update.
The installer visited this morning and checked all off the Powerwall / Gateway connections. All appeared fine. Tesla pushed an update to the Neurino module in the Gateway.
It now appears to be working correctly, time will tell if it continues to behave itself. I will keep you posted.

Grumpy_chap

@OP - congratulations on getting the solar system installed and it sounds like TESLA resolved the commissioning issues quickly. 

I wonder if you would be willing to share more about your experience of the purchase / installation process and also how much power is generated in different weather conditions?

I have a 6 m x 6 m direct south facing roof and considered investigating options for solar power based on generation, storage and hot water (so similar to what you seem to have installed). 

I found it hard to assess between different companies, how do you identify the reputable from the cow-boys? 

I did like the TESLA option (and trust the brand), but found even that confusing.  It seemed to me as though you needed to place an order online before they would come out to survey and quote, which seems wrong.  Also, when I did an on-line assessment it gave an indicative cost of £50k, which is absurd.

Do I need planning permission?

Does any electricity provider have to take and pay for the excess generation, or will I need to change tarrifs?  (Only recently signed a new tarrif.)

diveleader

Grumpy_chap said:

@OP - congratulations on getting the solar system installed and it sounds like TESLA resolved the commissioning issues quickly. 

I wonder if you would be willing to share more about your experience of the purchase / installation process and also how much power is generated in different weather conditions?
I will give you my initial impressions, but I'm sure more knowledgeable persons on here can also assist.
The installation was performed in under one day. (Scaffold was put up previously by the contractor). 4 fitters, onsite for approx 8 hours. The Powerwall was put in a detached garage, the Gateway and Solar inverter were fitted in the under the stairs cupboard. They were very neat and removed all debris, rubbish etc.

16x350W panels on my SSW roof. During the 30+ degree weather they seemed to peak at 4.88kW. However today, with showers followed by sunshine, I am seeing closer to 6kW.

I have a 6 m x 6 m direct south facing roof and considered investigating options for solar power based on generation, storage and hot water (so similar to what you seem to have installed). 

That's bigger than my roof! So you should get more panels than mine. At this time of year I'm generating more than I can use. This will change as the days shorten. 
I fitted an electric unvented water heater (we have a gas combi). to use some of the surplus. However, once you are on the Smart export G'tee, then it is more cost effective to heat your water with gas (if you already have it) than with solar PV, as you can get paid a higher rate for export than the cost of the gas. So, in hindsight, I wouldn't have gone down this route. (That said, our combi used to take a long time to get hot at the taps, so it may help my decision somewhat).

I found it hard to assess between different companies, how do you identify the reputable from the cow-boys? 
I had three local firms round and asked them lots of questions, this helped me to make a gut feeling on who seemed to be most professional etc.

I did like the TESLA option (and trust the brand), but found even that confusing.  It seemed to me as though you needed to place an order online before they would come out to survey and quote, which seems wrong.  Also, when I did an on-line assessment it gave an indicative cost of £50k, which is absurd.

Look for Tesla approved suppliers and contact them direct (that's what I did).
https://www.tesla.com/en_GB/support/certified-installers-powerwall

Do I need planning permission?
I don' t think so. You will need permission from the DNO is you are going to go above 3.88kWp though. Your installer will sort this out.

Does any electricity provider have to take and pay for the excess generation, or will I need to change tarrifs?  (Only recently signed a new tarrif.)
I think you can use a different supplier for your SEG, however, how they access your smart meter data I do not know yet.

Grumpy_chap

Thank you @diveleader.  Some very good information there.

Can you tell me, is this part typed the wrong way round?

diveleader said:

During the 30+ degree weather they seemed to peak at 4.88kW. However today, with showers followed by sunshine, I am seeing closer to 6kW.

Petriix

He's talking about the peak generation. Resistance increases with heat so, in prolonged direct sunlight in hot weather, the panels produce lower peak power. When it's cloudy (and even more so when it rains) and then the sun comes out, the system will generate at a higher peak rate.

Obviously you will generate more if the sun is out all day, but heat will reduce the output. Solar is more efficient in the spring when the days are cooler.

joefizz

Petriix said:

Obviously you will generate more if the sun is out all day, but heat will reduce the output. Solar is more efficient in the spring when the days are cooler.

Yeah, the panels data sheet should give the efficiency coefficient (drop off per increase/decrease in degrees C from standard).
When I put my solar extension on above the garage roof I put it on an angled frame to increase airflow to try to reduce the temperature of the panels. I also made sure the solaredge inverters were either in good airflow/shade or were well heat sinked but thats a different issue.

You can see this yourself if you have a flexible panel for a caravan/motorhome etc just play around with different placements/airflow in the same light.