SOLIS 5G Hybrid new install - GRID AC strange behaviour

[BlobbyBrown]

Hi
First post on here but have tried looking for the answer, so apologies if covered elsewhere.

Just had my SOLIS Inverter connected today. The Installer didn't really have much experience of SOLIS so walked away this afternoon thinking everything was working OK. I have been monitoring all afternoon and I thought all was OK, until the dinner was being cooked and I saw my main Grid meter spinning (previously it was stationary).

It would appear that the demand for AC on the GRID side, is not coming from the battery and is being drawn from the GRID, once the sun goes down. When there is enough PV power, earlier in the say, then the AC supply is being fed from the Inverter, sourced from the PV.

This is a 6kW Inverter so would expect the cooker hob to be sourced from the inverter.

I was also expecting any overnight demand to come from the battery.

Mode is set to Self Use. What else am I missing to get the Batteries and Inverter to draw from the battery when the PV is insufficient?

What's strange is that the CRITICAL AC Feed from the Inverter is powering my CRITICAL circuits which are on a different Consumer Unit/board, from the battery OK.

Thanks
Rob

 

[BlobbyBrown]

Inverter display showing low PV Power and Consumption going to Backup/Critical Feed but 0W to main House (GRID Feed). Will post similar tomorrow to hopefully show higher PV and House being fed from PV.

 

[rpdom]

Your inverter will produce what it can from the batteries when there is insufficient PV input. There are a few things that can limit that:

1) Limited by BMS - what batteries have you got connected? It may be that you are hitting the max current your batteries can supply. I've only got a 3kW inverter and my 2x Pylontech US2000Cs can supply up to 50A (25A each) which is 2.5kW.

2) Limited by inverter software. There is a Discharge Limitation value on the inverter that would normally be set to 0.0A, but if set to something else it will limit the available power from the battery. Oh, and check the fuses/breakers between your batteries and inveter. No point in setting this to 100A if your fuse/breaker is only rated at 80A.

3) Limited by inverter hardware. Your 6kW inverter has a max input from battery of 100A which is around 5kW. If your load goes over that you will pull from the grid.

If you've got a datalogger connected sending data back to the Solis Cloud servers you can look back at the graphs on the website and see how much current /wattage is coming from the batteries at 5 minute intervals. For a 3kW load, for example, I'd expect at least 63A/3000W from the batteries.

 

[BlobbyBrown]

Thanks.

I'm not seeing anything from the batteries at all for the load demand on the house side, even if it does hit some sort of limit.
Noticed this morning that putting the kettle on drew from the GRID rather than the inverter, whcih may just have been a consequence of the inverter not reacting quickly enough.

Regardless I'd still expect the overnight usage to come directly from the battery rather than the grid and that appears to not be happening.

The attached shows that the PV is supplying the AC Grid Side OK from the PV directly, this morning.

I've also got the default Time of use settings whcih don't seem that intuitive in terms of default setup and looks like you can't have any overlap between Charge and Discharge time slots.

 

[rpdom]

I've also got the default Time of use settings whcih don't seem that intuitive in terms of default setup and looks like you can't have any overlap between Charge and Discharge time slots.

Delete that Discharge time slot! That is sending all your stored battery power to the grid and not allowing it to be used for your load. Set the times to 00:00 for start and end.

Do you get cheap electricity from 22:00 to 08:00? That seems like a long slot for overnight charging.

 

[BlobbyBrown]

Do you get cheap electricity from 22:00 to 08:00? That seems like a long slot for overnight charging.

No, I don't have a smart meter and have not set up either export or have a different rate overnight. Do you think I should set that to 00:00-00:00 too?

 

[rpdom]

No, I don't have a smart meter and have not set up either export or have a different rate overnight. Do you think I should set that to 00:00-00:00 too?

Yes. Those times are only for charge and discharge from and to the grid. They are unrelated to your normal solar use, but if set they will stop the batteries being used during that time.

I have a smart meter and cheap electricity from 02:00 to 05:00, so I set it to charge up during that time if the next day isn't going to be sunny.
[edit]
I've just noticed that Optimal Income is set to STOP, an dthat disables the Time Of Use Charge Discharge settings completely. So you don't have to worry about that - you haven't just wasted a load of money by charging your batteries from the grid and then giving it all away for free.

SeaGal's suggestion of the CT clamp being incorrectly fitted is the most likely cause. It should be on the Live supply wire from the grid - either just before or just after the meter, with the arrow pointing towards the grid supply. If the arrow is pointing the wrong way the inverter will get import and export the wrong way round and you'll see funny readings like the ones you've got. You can unclip the sensor and put it back the right way, or there is a setting on the inverter to say it it reversed.

 

[SeaGal]

Welcome! The issue to me looks like the CT clamp is not positioned correctly - i.e. not measuring grid import or export.

The image of the Solis screen from last night is not showing any house usage from the grid. Hence, the Solis won't try and export any as it doesn't think you are using any power.

Has the 'so-called' installer added the CT clamp between the Solis ac-grid connection and your CU, rather than between CU and meter/DNO supply?

 

[SeaGal]

Additional observation. I think my assumption in my post above is likely correct. In your image from this am when you have 3kW+ of PV generation, the screen is showing all of that going to the house and none being exported.

Unless your house was using _exactly_ the same amount of PV being generated, then I would expect some grid export.

Get the installer back to rectify.

 

[BlobbyBrown]

Welcome! The issue to me looks like the CT clamp is not positioned correctly - i.e. not measuring grid import or export.

The image of the Solis screen from last night is not showing any house usage from the grid. Hence, the Solis won't try and export any as it doesn't think you are using any power.

Has the 'so-called' installer added the CT clamp between the Solis ac-grid connection and your CU, rather than between CU and meter/DNO supply?

CT is on the main cable between Main Meter and CU on the thick brown/LIVE wire.

I do howver suspect the CT to be at fault here though as I'd expect demand to be picked up by the CT and it isn't even registering on the data as being Power drawn from the grid.

Installer did blow the original Eastron SDM120CTM Meter (by connecting the CT tails to the LIVE without isolating first) which we replaced with a OBD115 meter and new CT. I do have a replacement Eastron ordered.

 

[SeaGal]

SeaGal's suggestion of the CT clamp being incorrectly fitted is the most likely cause.

@rpdom... you been going 88 miles an hour in your DeLorean again? ?️

 

[BlobbyBrown]

Additional observation. I think my assumption in my post above is likely correct. In your image from this am when you have 3kW+ of PV generation, the screen is showing all of that going to the house and none being exported.

Unless your house was using _exactly_ the same amount of PV being generated, then I would expect some grid export.

Get the installer back to rectify.

Yes I was observing this too and was a little concerned about that much power going into the CU and not being utilised/exported. I thought there was a different fault with the inverter

 

[BlobbyBrown]

Dodgy CT Clamp perhaps?

Light on KWH meter is flickering so it is registering something.

 

[SeaGal]

CT is on the main cable between Main Meter and CU on the thick brown/LIVE wire.

I do howver suspect the CT to be at fault here though as I'd expect demand to be picked up by the CT and it isn't even registering on the data as being Power drawn from the grid.

Installer did blow the original Eastron SDM120CTM Meter (by connecting the CT tails to the LIVE without isolating first) which we replaced with a OBD115 meter and new CT. I do have a replacement Eastron ordered.

Not familiar with an OBD115... I thought the Solis only supported Acrel (which I have) and the Eastron. Does the OBD one show anything on its screen?

If it does, guess its not compatible with the Solis, if it doesn't then faulty CT clamp likely. Though I'd want to get the installer to rectify this with approved / supported power meter.

 

[BlobbyBrown]

Not familiar with an OBD115... I thought the Solis only supported Acrel (which I have) and the Eastron. Does the OBD one show anything on its screen?

looks exactly the same as the Eastron, but it could, as you say, just be an incompatibility somehwere. I've checked baud rates etc and all match up.

Will get him to swap it out. It is almost as if the inverter isn't seeing the demand come in.

Kettle is still drawing from the grid rather than the inverter as PV KW has dropped down since this morning. When it was at 5kW it didn't draw from the grid.

Thanks for your help, so far I'll report back.

 

[SeaGal]

Keep us updated. Looks like baud rates etc. are OK, as the Solis is reporting "RS485 OK", so it is seeing and communicating with the power meter. You say 'light on meter is flickering'... does it not have an LCD screen to show grid power / voltage etc?

I'm not near my Solis at the moment, but do I remember there is a configuration setting for Acrel vs. Eastron? If so, maybe that is set incorrectly?

Yes, I agree, your Solis is not seeing any grid usage - the stripy yellow arrow on the Solis screen between meter and the grid pylon is showing 0.00kW.

Hence, your kettle will be powered by PV when the sun is out and the grid when the clouds come over

 

[rpdom]

@rpdom... you been going 88 miles an hour in your DeLorean again? ?️

Well, my Fiesta, perhaps... I did put "[edit]" to show that I had edited the post later.

do I remember there is a configuration setting for Acrel vs. Eastron?

Yes, that's what it has.

 

[BlobbyBrown]

Keep us updated. Looks like baud rates etc. are OK, as the Solis is reporting "RS485 OK", so it is seeing and communicating with the power meter. You say 'light on meter is flickering'... does it not have an LCD screen to show grid power / voltage etc?

I'm not near my Solis at the moment, but do I remember there is a configuration setting for Acrel vs. Eastron? If so, maybe that is set incorrectly?

Yes, I agree, your Solis is not seeing any grid usage - the stripy yellow arrow on the Solis screen between meter and the grid pylon is showing 0.00kW.

Hence, your kettle will be powered by PV when the sun is out and the grid when the clouds come over

Meter set in Inverter is set to "Eastron 1Ph Meter", if I change to "1Ph Meter" then I get a RS485 Fail problem, so for this type of meter it's communicating with the inverter OK. There is another setting for the "Acrel 1PH meter", which is a different setup altogether.

The LCD is showing a minus(-) Wattage value which I presume means it's from the Inverter, rather than from grid?

When i put the kettle on the figure doesn't change but my main supply meter starts turning (old disc spinny one). I'd expect it too?!

 

[SeaGal]

When i put the kettle on the figure doesn't change but my main supply meter starts turning (old disc spinny one). I'd expect it too?!

Me too. The odd thing is that if the meter or the CT clamp was faulty I'd expect a zero value, rather than showing a specific value - what wattage is it showing? And does that value change with amount of sunlight?

Putting the kettle on should, of course, change the figure unless the kettle's power is not being routed via the wire the CT clamp is on.

If the power meter is showing a value that changes with the sun and putting the kettle on doesn't change that value, then double check the meter is where it should be. I know you said it on live between meter and CU, but do you have any other connections between those two, like I have for night switching of economy 7 or similar?

 

[BlobbyBrown]

If the power meter is showing a value that changes with the sun and putting the kettle on doesn't change that value, then double check the meter is where it should be. I know you said it on live between meter and CU, but do you have any other connections between those two, like I have for night switching of economy 7 or similar?

No, simple single feed setup, no Economy 7 , single reading analogue old style spinning supply meter

KWH LCD Value is changing under load. At the moment all roof is being fed to the CU - all 6kW, so Kettle is not drawing additional from the grid.

From my tests last night the LCD value goes negative when excessive more than PV is being demanded and at that point the GRID meter is spinning, so conclusion is still the inverter is not reactiing to the negative demand and filling that with KW from the Battery.

What's sllightly inconsistent is that the Critical AC feed to the second board for my Backup circuits are all being fed from the battery by the looks of it when the PV is low.

So comes back to the Meter demand comms with the Inverter.

New Meter arriving today so will be able to update shortly