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ciaram-granger avatar image
ciaram-granger asked

ESS with an option to Ignore AC input

Hi All

We have been coming across sites with high grid voltage, where we have some ESS systems installed these sites have PV on the Output side of the inverter. Due to our local requirements for PV inverters the grid voltage is so high that the PV won't ramp up to produce enough to charge the batteries.

We still have some legacy systems that run with the HUB2 v3 Assistant and its great for ignoring the AC input with PV on the output side.

Just checking to see if anyone else is in need/or there is a demand of a Ignore AC input on the ESS assistant when there are AC coupled PV inverters on the output, seen as though HUB2 has been depreceated.



ESS
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5 Answers
Alexandra avatar image
Alexandra answered ·

@Ciaram Granger

If it is grid voltage that is an issue then you can narrow the accepted grid voltages. Then the victron will disconnect and ignore it automatically.

That is the simplest way. Otherwise the generator start stop can be used as well or an an ignore assistant but this removes the ess assistants nice features.

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ciaram-granger avatar image ciaram-granger commented ·

@Alexandra, Thanks for your response. The issue with narrowing the grid voltage is if the grid voltage remains out of range and the system is discharging the battery it won't cross back to the grid once the battery is discharged and fault/shutdown due to low battery.

With the second, the beauty with hub2 is it passing into passthru mode once it hit a SOC point. Im not quite sure this can happen with general flags or any other assistant. I may be wrong on this though.

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Alexandra avatar image Alexandra ♦ ciaram-granger commented ·

@Ciaram Granger

The article that may interest you is https://www.google.com/url?q=https://www.victronenergy.com/live/assistants:ignore_ac_input_using_the_generator_assistant&sa=U&ved=2ahUKEwjtieOG7e3rAhXJTxUIHVDoBN4QFjAAegQICRAB&usg=AOvVaw1sa6iLSUSFok6XCh7_9h77

I have used this in several systems but not with pv on the output.

What I can say is that the two do not go well with each other that the ess assistant battery percentages will be overridden by the ac ignore one. You may have to switch to the pv inverter assistant as you technically have an off grid set up with the grid as your backup generator.

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thomasw-1 avatar image
thomasw-1 answered ·

yes, I am also looking for an option to separate AC-input on demand in ESS mode - in best case externally controlled (e.g. writable Modbus-register to GX) or at least similiar to Hub-2 app in dependency of remaining battery capacity and current AC-out load (avoiding overload situations)

With that option I could solve the the poor zero-feed-in control and the Fronius throttling issues, which are not properly suported by ESS.

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shaneyake avatar image shaneyake commented ·

Your wish has been added.

Modbus Register 33
com.victronenergy.vebus - Switch Position - 33
1=Charger Only;2=Inverter Only;3=On;4=Off

If you set it to "3:On" then it will run ESS like normal, if you set it to "2:Inverter Only" it will disconnect from grid.

You will need GX firmware 2.70 or greater.

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guydusautoy avatar image
guydusautoy answered ·

I think ESS with AC Ignore would be useful to optimise use of PV for loads and battery charging and automatically connect to the grid when battery state of charge is low or loads are high.


It will also almost totally remove nuisance losses of grid and inverter overloads with an unstable grid power supply.

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seriusrod avatar image
seriusrod answered ·

I would sign in for AC Ignore with ESS. In fact I've tried it by adding the general flag and relay assistants, but ESS control overrides it. It should look for external general flag override as other assistants do.

Virtual switch does not address the energy flow, (after the contidion that switched on disappeared) in a non feed-in allowed region.

Nor modulates PV Inverters output.

So there's no satisfactory solution for domestic installations.

EDIT: It's not that ESS overrides it, it's a bug where after some hours, the relay assistants based on conditions stop working.

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Alexandra avatar image Alexandra ♦ commented ·
Ess and ac ignore cannot be used in the same system.

You can add a contactor on the ac in that is signalled by the gx generator function in the gx. That way it is interactive in use you can connect 9n soc or time of day etc.

An ac ignore is rigid in its setup and yes ac ignore and ess are in conflict so cannot be used together. In fact somewhere in the documents it says you should not use the two together.

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shaneyake avatar image shaneyake Alexandra ♦ commented ·

This is not true. I am running ESS with Ignore AC.

You setup ESS like normal. Then use AUX input to set General flag via assistant.
General Flag then sets Ignore AC via assistant and the system disconnects from grid.

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rainer avatar image rainer shaneyake commented ·

It seems that some people have difficulties using ESS with AC ignore. I would need this combination, whereby AC ignore is switched on for some hours per day only. The power supply from the grid has voltage spikes which destroys some electrical equipment, therefore I want to disconnect from the grid during the time when using electrical equipment that is more sensitive towards voltage spikes.

I can see 3 possibilities to implement AC ignore with ESS:

1) AC input is disconnected with a timer controlled contactor, therefore no Victron equipment used for disconnecting the AC input.

2) Timer sets AUX input. AUX input to set General flag via assistant.
General Flag then sets Ignore AC via assistant and the system disconnects from grid. (proposal in this thread by shaneyake)

3) Generator assistant sets start and end time for the general flag to ignore AC input.

I would prefer to implement the 3rd possibility because there would be no need for additional equipment. Is it working, does anybody have experience with that?

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shaneyake avatar image shaneyake rainer commented ·
2) can be triggered from GX relay. So you don't have to add anything you don't already have. Also makes it easy to monitor what is going on.
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seriusrod avatar image seriusrod shaneyake commented ·

@Alexandra

Yes, I've arrived and deployed that said configuration. But soon after I found this new bug on 48x fw versions that makes that (at least) relay assistants stop working after some time. Hours.

I've also removed the ESS assistant from the equation, in case it created interference, but no. If you try to emulate a VS configuration with assistants with new versions, they work in tests, but after some hours, they stop triggering. Even triggering the AUX relay fails.

That's nasty, as I created an emergency grid contactor trigger and it didn't work and my inverter entered overload several times. During tests it worked flawlessly.

And Victron staff is not interested in such a dangerous issue.

PS: A "manual" or "physical" disconnection from the grid is not feasible, as I need to complement with grid power.

EDIT: I would ask to people that uses assistants like this with newer fw versions (don't upgrade for it) to check if can trigger a relay based on conditions like load or battery voltage, after some time of use.

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rainer avatar image rainer seriusrod commented ·
@seriousrod It seems that the firmware is not stable when the solution stops working after some hours, which is really disappointing. Anyway, I will also try this myself when I set up the system in a few months from now.
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ponzoa avatar image
ponzoa answered ·

I would be really interested to have a feature like this. In my case, I would want ACIn only below certain SOC or above certain SOC but ignore ACIn in the mid ranges.


This would allow my clients to use the grid when the batteries run low, use solar and the batteries between certain times independant of the grid to protect their system, and export power to the grid when above a certain level of SOC, say 95% when working with LIFEPO4 for example.

I'm not sure the AUX In option would allow this.

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shaneyake avatar image shaneyake commented ·
The best way to do this is with the Large version of GX firmware, you can configure this in NodeRed pretty easily.


Else you can use AUX input to trigger ignore AC and connect AUX to GX relay and control that with the generator options.

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Ovidiu Stan avatar image Ovidiu Stan shaneyake commented ·
How can you control the Ignore AC IN within Node-Red? Have you found a way ?
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shaneyake avatar image shaneyake Ovidiu Stan commented ·

Yes, you can change the switch position node.
On will connect AC input and invert
Inverter Only will disconnect AC input.


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seriusrod avatar image seriusrod shaneyake commented ·

Inverter only will also keep the multiplus from charging the batteries from a solar inverter.

Not a solution to me.

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daniel-feist avatar image daniel-feist seriusrod commented ·
I just tried this approach and my battery is still charging using excess PV! PV is ac-coupled on AC-OUT1, not DC though.


Looks like it's deciding to charge (even though Multiplus is in inverter-only mode), rather than use frequency shifting to limit PV output.

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nickdb avatar image nickdb ♦♦ Ovidiu Stan commented ·
@Ovidiu Stan I will reply to you on the duplicate question you have on the modifications section.
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CM avatar image CM shaneyake commented ·
Still using ESS with ignore AC input ?
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