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flutemaker avatar image
flutemaker asked

It seems that ac2 out is not working in self consumption mode but just pulls power from grid

Up to now I have not used AC2 and the system an ess utilising a multiplus 2 with mppt's and pylontech batteries has worked beautifully. However, having tried out my new configuration with the ac2 now connected to my hot water tank I find that when I switch AC2 on via the VRM switch that I have configured, power is only drawn from the grid to power the heater not from the solar panels or batteries.

Ac1 is not used the ess being driven via the AC in.

I am scratching my head with this as I believed that I thought AC2 out would behave the same way as AC1 and AC power in. Am I wrong in this assumption or do I need to enable something or another in settings?

ESS
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flutemaker avatar image
flutemaker answered ·

Problem Solved and all of my fault.

I had wired the com (-ve) from the Cerbo GX to the positive of the multiplus. I am old and stupid and my eyes are not as good a they were.

I have re tested everything using the switches and the Ess carries on as normal.

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nickdb avatar image nickdb ♦♦ commented ·
Oops :)

Please add the solution to your crosspost on discourse. Thanks

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kevgermany answered ·

That's how it's supposed to work. Idea is the heavy consumers go there and don't flatten your batteries.

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ton-gans answered ·

In Venus O.S. do you have set Self-consumption from battery tot All system loads in ESS?

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flutemaker avatar image
flutemaker answered ·

Thanks for the replies.

Firstly the ac2 is not even pulling power from the panels let alone the battery just straight from the grid. I have a diverter box on my hotwater tank input so that it can be toggled between the household consumer unit and ac2. When on the consumer unit ess works just fine, panels provide power to heat the hot water. However when on the AC2 circuit power for the hot water is only drawn from the grid.

Regarding the other answer, in venus OS settings are set to mode optimised with battery life and self consumption.

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ton-gans answered ·

That's Mode. What setting is: Self-consumption from battery (All system loads or Only critical loads)

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nickdb answered ·

AC1 and AC2 are the same, they are connected via a relay that opens by default on grid-loss.

The inverter can't treat the two outputs differently as they are the same.

If the behaviour is off, it's because your config/setup is off, or you are exceeding limits and the balance is being grid powered.

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flutemaker avatar image
flutemaker answered ·

Thanks Tons-Gans. I cannot find that setting on my cerbo gx. I seem to remember that there is an advanced mode for the cerbo but I cant remember much about it , but anyway that setting is not available.

Re nick db, yes thats exactly what I expected AC1 and AC2 to be exactly the same but up to now I cant find out why they are not.

Currently I am trying to find out about the self consumtion fro battery..


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nickdb avatar image nickdb ♦♦ commented ·
Does the remote console show an ESS state # followed by a number?

What is the state under the inverter show?

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ton-gans answered ·

I think that setting is only there when there is a grid meter in the system. I've got a grid meter, perhaps that's why I have that setting.

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flutemaker avatar image
flutemaker answered ·

Ahh, I was wondering wether this could be a metering problem. I have a current sensor clamped on the incoming mains tails and it works very accurately indeed. I cannot understand wht this would work on ac in yet not on ac2 if they are all connected??

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nickdb avatar image nickdb ♦♦ commented ·

The CT will enable export for parallel loads but the advanced options require a meter.. The ESS/inverter setup would need to be correct to enable any AC OUT to be powered via battery.

It is most likely that ESS is preventing it due to thresholds set, screenshots will show this. Often it is batterylife that is the cause, having an elevated active SOC.

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flutemaker avatar image flutemaker nickdb ♦♦ commented ·
Thanks nick. Im guessing this has to be done in the multiplus itself and not via remote console
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nickdb avatar image nickdb ♦♦ flutemaker commented ·
No, the remote console will show ESS and inverter state on the main dashboard tile.
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flutemaker avatar image
flutemaker answered ·

I have just done an experiment. Without having the water heater turned on which is the only place AC2 goes to when I enable AC2 and the contact is heard opening then the mppts stop and mains ac covers all of the loads- essentially the whole solar system turns off.

All that I have done that is different is to enable AC2 to be switched on...

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nickdb avatar image nickdb ♦♦ commented ·
How are you doing this?
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flutemaker avatar image flutemaker nickdb ♦♦ commented ·

I isolate the water heater so that the ac2 in effect goes nowhere. Then, I turn on AC2 via the relay 1 switch on my dashboard...

AC2 clicks in and then power flows in from the mains to cover any loads that are running.

It is as though switching that switch turns of all of the ESS and powers everything via the mains.

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flutemaker avatar image
flutemaker answered ·

I isolate the water heater so that the ac2 in effect goes nowhere. Then, I turn on AC2 via the relay 1 switch on my dashboard...

AC2 clicks in and then power flows in from the mains to cover any loads that are running.


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nickdb avatar image nickdb ♦♦ commented ·

Ok, but you are not switching the AC2 relay, you are switching a contactor that is attached to AC2 before the geyser/loads. (The actual AC2 relay is switchable via an assistant).

Load a screenshot of the remote console when this is happening.

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flutemaker avatar image flutemaker nickdb ♦♦ commented ·
Yes I have programmed two assistants one to open and one to close. You can hear the relays clicking....
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flutemaker avatar image flutemaker flutemaker commented ·
as for loading pictures for some reason I keep on failing in this endeavour. My Safrai browser is probably way out of date. When your looking at the cosole, all of the panels are showing out put as you would exoect, loads fulfilled but the when you operate the dreaded switch then both mppts go to zero and all loads are filled by the grid....
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flutemaker avatar image
flutemaker answered ·

cannot upload pic; parsing effect failed

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nickdb avatar image nickdb ♦♦ commented ·
Yip. Broken function. Have to post it elsewhere and then put the link here, or move to the new forum that is being tested. Links in modifications section.
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flutemaker avatar image
flutemaker answered ·

progress has been made- narrowing down the problem. I delated the scripts that operted the ac2 via the virtual relay switch on the dashboard and installed a script that allows ac2 to be turned on and off due to battery state of charge. This is working spot on.

However, I thought that I would just see what would happened if I switched the virtual relay on when it had NO scripts attached to its function. When I did this the same thing happened as before, all of the mppt's turned off and the ess system ceased to function.

Could it be that when the switch is operated, the Cerbo GK looks for a power meter and when it cant find one (because I am using a current clamp) it causes the multiplus not to see the clamp readings?

I am not the first to notice this untoward functionality; https://community.victronenergy.com/questions/252446/multiplus2-ac-out-2-control.html

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nickdb avatar image nickdb ♦♦ commented ·
If any of this uses virtual switch functionality, that is not compatible with ESS. Installing the ESS assistant requires virtual switching to be disabled, forcing it on will prevent ESS operating.
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flutemaker avatar image flutemaker nickdb ♦♦ commented ·
Hi Nick, VS is disabled in the multiplus config.When I say virtual I referring to the switch that appears int he control section of the Victron dashboard. That operates a switch on the cerbo which is hard wired through to the multiplus.... ( I believe)
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flutemaker avatar image flutemaker flutemaker commented ·
On my set up the cerbo relay 1 and 2 outputs are wired th the Aux 1 and 2 inputs
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nickdb avatar image nickdb ♦♦ flutemaker commented ·

Flicking the switch on its own does not do anything to Cerbo logic. I can flick mine on and off and it has zero effect.

It is more likely the behaviour, or default behaviour, of activating the aux port.

You could test this by switching it externally outside of the Cerbo.

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flutemaker avatar image flutemaker nickdb ♦♦ commented ·
Ive just done it again, toggled relay 2 and it resulted in the mppts going down. I have previously removed any scripts to do with this so nothing should be happening. I think Ill just leave things as they are be grateful that the water heating is working and not use relay 2 again.

I

Thanks for your help

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flutemaker avatar image
flutemaker answered ·

I should have mentioned from the relay ports of the cerbo to the Aux ports of the multiplus.

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