Batteries not charging

[Meadowlark]

I have had rooftop solar PV for a few years but have recently added two Pylontech batteries and Solis AC coupled inverter.
I would also like to charge from cheap rate night time electricity from the grid.
The Solis instructions and Apps are pretty useless in my opinion and not easy to use or follow. But I thought I had set up "self-use" correctly to do this.
Anyway, the batteries appear to charge from the grid overnight, but it seems that they are instantly discharging back to the grid! The stored electricity is certainly not being used that quickly in the house - unless I switch on the Optimise immersion heater - which immediately starts up and therefore seems to prove my point.
Yesterday and today we had quite a lot of winter sun, but my batteries show no sign of being charged, but the immersion heater kicked in again.
My priority is for the batteries to be charged. The immersion heater should only come on when excess unused electricity is being exported after house usage and battery charge is complete.
What am I doing wrong? Or is there a fault?

 

[SeaGal]

Sounds like you have set the Solis to 'self-use', which is required and correct.

But did you set a 'discharge time' as well as a 'charge time'? - if so that is the error.

This guide summarises the settings well...

Solis Hybrid Inverter: charging from the grid

How to configure your Solis Hybrid Inverter to charge from the grid on schedule.

blog.jonsdocs.org.uk

 

[Meadowlark]

Thanks.

Yes, I mentioned in my original post that I set up self-use.

Discharge time set to 00.00 - 00.00.

I had see that guide too. I followed that as far as was possible, but it's not the same rev software as mine. However the settings are pretty much the same.

 

[SeaGal]

In that case is the grid CT installed correctly and working?

 

[Meadowlark]

It is installed, but how do I determine if it is working properly?

 

[Meadowlark]

Edit:. I have scrolled through the menu to CT Info which shows mains voltage at 240, current at 0, and power at 0, which is what I would expect at present as I am neither importing or exporting electricity. Is this OK? Is there a test procedure?
It is dark here now and the batteries are discharged.

 

[Meadowlark]

Edit:. I have scrolled through the menu to CT Info which shows mains voltage at 240, current at 0, and power at 0, which is what I would expect at present as I am neither importing or exporting electricity. Is this OK? Is there a test procedure?
It is dark here now and the batteries are discharged.

 

[Meadowlark]

Further update. Although the meter CT is apparently functioning, there is nothing plugged into the CT connection on the inverter, where the PV input should be!
Could this be the problem? Apologies for the dumb questions but this was installed "professionally" but not yet working and I am getting nowhere with the installers.

 

[SeaGal]

I have scrolled through the menu to CT Info which shows mains voltage at 240, current at 0, and power at 0, which is what I would expect at present as I am neither importing or exporting electricity. Is this OK? Is there a test procedure?
It is dark here now and the batteries are discharged.

If batteries are discharged, I would expect there to be import from the grid to power the house.

Further update. Although the meter CT is apparently functioning, there is nothing plugged into the CT connection on the inverter, where the PV input should be!
Could this be the problem? Apologies for the dumb questions but this was installed "professionally" but not yet working and I am getting nowhere with the installers.

Is that an Acrel CT meter and you can see data on its LCD screen?

Not sure what you mean by "nothing plugged into the CT connection on the inverter, where the PV input should be" - the CT connection and PV connection are separate and very different (physically and electrically) to each other.

Does the Solis main screen show RS485 working on not?

OK, so not a DIY solar install then = need to put more pressure on the suppliers.

 

[Meadowlark]

If batteries are discharged, I would expect there to be import from the grid to power the house.


Is that an Acrel CT meter and you can see data on its LCD screen?

Yes. Says 700W at present on the sensor screen, but the sun is shining and my immersion heater is heating, so I assume this is export power? As mentioned earlier my immersion heater should not switch on until my batteries are charged There is no sign of them charging.

Not sure what you mean by "nothing plugged into the CT connection on the inverter, where the PV input should be" - the CT connection and PV connection are separate and very different (physically and electrically) to each other.

There is no cable plugged into the CT connection on the inverter.
I think I understand that the CT and PV measurements are different quantities from different places. Are you saying it doesn't matter if there is nothing in the CT socket?
The sensor cable from the Acrel is plugged in to the "meter" connection.

Does the Solis main screen show RS485 working on not?

Not sure how I access that yet....I'll have another look.

OK, so not a DIY solar install then = need to put more pressure on the suppliers.

Yes. Indeed. Tell me about it.
Thanks for your help so far. Much appreciated.

 

[SeaGal]

We have a Solis hybrid, so only one CT connection to the Acrel meter. I _thought_ the non hybrid version has 2 CT connections; one for grid and one to measure existing PV generation, but not 100% sure ?‍ - do you have the solis install instructions at all?

 

[Meadowlark]

We have a Solis hybrid, so only one CT connection to the Acrel meter. I _thought_ the non hybrid version has 2 CT connections; one for grid and one to measure existing PV generation, but not 100% sure ?‍ - do you have the solis install instructions at all?

Unfortunately not.
It's a RAI - 3K - 48ES - 5G
The only documentation I have is what I have managed to glean from the Internet.
But this documentation seems to me to show two sensors.
I now also suspect the CT is either in the wrong place or not communicating to the inverter - as you suggested. Any ideas how I can easily check the RS485? I cannot find that on the on-screen menu.

 

[SeaGal]

My RHI (hybrid solis) shows the RS485 on the graphical main screen and OK or FAIL by it.

But see this posting (figure 4.12)...

Solis RAI 3K AC - no discharge, shows as operational but no contribution to household load?

Hello folks, Noob here though hoping there's a bit more of a knowledge base than some of the other forums! Background - I already have 4kWP of PV on a SolarEdge inverter and picked up the Solis RAI AC-coupled with a view to using 48V of leisure batteries that I originally had for a UPS. The...

diysolarforum.com

It looks like you need both the meter and CT connection

 

[SeaGal]

Also, where are the batteries / what temperature are they at?

 

[Meadowlark]

It seems the problem was simply that the CT clamp was on the wrong side of the meter!! That and a system reset seemed to be required...not sure why but perhaps due to the batteries discharge level being too low?
I think it is now all working as planned. At least the batteries charged in the sunshine today, began discharging when the sun disappeared and there was not sufficient excess electricity to power the immersion.
It is programmed to import from the grid tonight on E7 tariff. Fingers crossed.