question

Thanks again Alexandra, I appreciate the comments. I am also concluding that the trouble is a reluctance of the batteries to 'wake up' but have no knowledge as to how 'wake up' is signalled. (Thus my email to Pylon, but no answer.)

Disconnect from grid will prevent export of power and the house will run from batteries but . . .

I have previously tried setting zero feedin and am pretty sure it made no difference, because if the batteries won't move from 'idle' then presumably the power has to go somewhere. However, export was permitted at the time of posting. I have now turned it off again to check.I'll watch what happens.

In the hope that it might help here are the graphs from today.

To me they clearly show unwanted feed in of solar power. If you combine this unwanted export of solar power with the power cost of running the system then it would seem the best thing to do is to disconnect the ESS system outside of summer. Such a pity.

David

Just for clarification what do you have measuring the grid use and feed back is it ET112 or similar?

Just checking as I know the ferrite cores are slow to react etc. so avoided that and went for a ET112.

I some times see a bit go back to the grid but not 200W and how long have you been running ESS? as mine took a while to settle after it was set up.

Your ESS setup page is set for "Total of all phases" which is only appropriate if you have a 3-phase setup, maybe that is the problem.

The internal CT is actually faster than an external meter so I doubt that is the issue. However it might be the response time of the Modbus connection to the Solaredge. If this is connected on the AC-Out it will actually work OK without any data at all from the PV inverter (though you will not see the generation figure separately, it just looks like a negative load), you could try that.

@sharpener That part of the set up puzzled me as well but the Victron ESS guides states 'For single-phase systems, this setting has no effect and can therefore be ignored.' I have just gone to change it and it and I get some pretty scary warnings. Have you done this yourself, can you provide reassurance. I don't have the knowledge (or confidence) to overule Victron's guidance.

Thanks very much for the feedback, it is all helping - although the eureka moment has yet to arrive.

David

Mine has always been set to Individual Phase. I have just had a look, I think the warnings in white on black apply only to a 3-phase setup. I don't think you will come to any harm if you change it but it is a bit of a long shot, if the solaredge is on the AC-Out I would try disconnecting its modbus to begin with.

This simply an update on the above. I explored all the suggestions above but little if anything changed (but many thanks for trying to help). That included turning off Modbus, which I expected to result in a loss of communication between the Cerbo and ac coupled Solaredge inverter, but no, eveything continued as before! Presumably communicating over the LAN.

Three weeks ago I sent a message to the Victron dealer via the reseller asking if the situation above is normal and expected. Disappointed to have received neither acknowledgement nor reply. I must assume that whilst the ideal is to use available PV power to power the ac loads, then charge batteries and then export to the grid is the ideal the Multiplus cannot in fact achieve this when surplus power after supplying house loads is low i.e. <200W.

Over winter, ie the next 2 months, this makes no difference as it is very exceptional for PV power to exceed the house base load. Over summer, i.e. April to September these extra 'loses' should not matter as PV energy will exceed the house demand. It is the shoulder 4 month period in between when this will show up. Pity, but heh hoh, everything else seems to work fine and as expected.

It's all a learning curve.

Do you have any AC loads at all on the input side of the multiplus? Where is the input fed from?

Oops @Gazza I missed your comment. No loads at all in input side. Uk National Grid is collected to ACin. House load is connected to ACout1 (including the Solaredge PV Inverter. This to allow house to function as normal in case of power cut (unlikely as that may be).

You mention 2 x Multi II 48/10000 which I take are in Parallel. My understanding is that Parallel is only supported upto 48/5000 and that the 8, 10 / 15KVA units don't accept parallel setups (something I hope is solved shortly via firmware). If this is the case, could this be what's causing the lag?

Have you tried the uk pylontech email: service.uk@pylontech.com.cn

Thanks for continued suggestions - always very much appreciated.

1) There is only 1 x Multi II 48/10000, sorry for that confusion.

2) At the beginning I did email Pylontech. As reported by others I recieved no response or acknowledgement from them. Has anyone had any joy on that front?

I think I just need to accept things as they are, perhaps a future firmware update may help. Several details of the Multi operation seem mildy strange. In the evening when the grid is 'passed through' with minimal background load and no battery charging, often you hear an acceptable low intensity hum, on other occassions under apparently identical load conditions the mains hum is very loud. When this happens the difference between ACin power and ACout power is much greater. Something (some grid parameter?) seems to cause some internal algorithm to start working overtime for no obvious reason. But that's another subject!

All the best

David

I'm not surprised to read what @ajmacleod reports and also suspect that AC coupled PV makes it harder for the system to control import/export.

Regarding comments from @1234enough I can confirm that the readings for V, I and P are inconsistent. The Smart meter on the grid supply reported an export kWh figure which was roughly consistent with the power display on Victron over time. The current reading is the most suspect and at lowish power is usually recording a current 2x or more than you would expect from a simply V I = P calculation. No idea how the unit determines the power if the current reading is so far out.

I did experiment with grid set point and disabling feed in (as shown above) but these changes had little, if any, noticable effect on the lack of battery charging.

When I eventually succeed in moving to a 'time of day' tariff and start to charge the batteries at night I can only hope that the ESS system does discharge the batteries during the day rather than taking in the expensive daytime grid power. At least then I have the option of disconnecting the grid during daytime as a last resort!

Regards and thanks to all.

There seem to be some similarities to this thread https://community.victronenergy.com/questions/147417/simple-grid-connected-multiplus-ii-4810000-and-pyl.html.

Perhaps break the problem into three parts:

• Disconnect the PV inverter completely (AC and all data connections), does the system then work correctly as an ESS, charging at night and discharging by day? Does it keep it at a constant grid setpoint? This setup is like the above link, and needs to be sorted first.
• If OK re-connect the Solaredge AC (but not the data) at a time the house loads are more than the PV output, so it should simply reduce the apparent load. Does it still keep the grid setpoint constant as the sun goes in/out?
• If yes, the problem is with the speed of response of the solaredge data. Maybe use an ET112 instead, I have a Multi 5k set up like this with dumb PV inverter, works fine. But perhaps the problem is a peculiarity of the Multi 10k as you and @NetZeroDude both seem to have similar issues?

Thanks @sharpener on all counts. The other thread is very interesting and useful. Gives me more hope that if I do succeed in moving to an Eco 7 tariff (it is taking forever) then it my set up should work.

Your logical approach re ESS noted, and will be used if needed when Eco 7 ESS finally set up. I have previously explored the solaredge data delay theory to no avail, but not as rigorously as you suggest. Superficially the PV readout on the Touch Screen display is realtime in that the readings fluctuate constantly as expected with varying cloud cover. However, as I cannot view the Solaredge and Victron displays simultaneously, I would be unaware of consistent time delay of several second which, if present, could confuse matters. This still does not, in my head, account for the refusal of the system to start charging the batteries when there is acontinous PV power excess over AC loads of 150W to 200W.

I did not fit a changover switch as shown in @NetZeroDude thread and advised by you, but have been considering it. Now thinking I should do that - thanks. Your time responging is appreciated.