question

Brian Brown avatar image
Brian Brown asked

Ignore AC input VS function not working

I have (2) Quattro 48/5000/70-2x100 120V (FW v494) running in split phase. 95% of the time I'm in an off grid configuration but if I don't have sun for a few days (or I'm testing) I'll provide AC via the grid to the AC-2 inputs. I have setup the virtual switch to ignore the AC inputs unless the criteria is met (see configuration). The problem I'm having is I provide AC to the inputs but the Quattro's switch from inverting to AC passthrough plus charging even though the conditions haven't been met. Can some check my configuration to see if I have done something wrong? When I first installed the system this function worked properly. I used VRM remote configuration to download and make a a couple of charger configuration changes then upload. Even though VRM configuration upload didn't require a restart of the Quattro's do they need to be restarted? L1 & L2 Quattro's are configured identically.

virtual switch
l1-config.pdf (298.4 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
@Brian Brown

The system does not always require a restart.

Did you re download the config to check everything uploaded correctly?

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Brian Brown avatar image Brian Brown Alexandra ♦ commented ·
Yes. The above config PDF was printed from a fresh download today. Anything in the config that would explain why it is switching? The battery was fully charged and the AC load was ~400W so it shouldn't have switched to the AC input. I'm using an external SmartShunt for the battery monitor, not the inverter battery monitor. Everything is hardwired networked through a Cerbo GX.
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10 Answers
JohnC avatar image
JohnC answered ·

Hi @Brian Brown

Try changing the entries you have for the times there in VS for "0" (zero) to something realistic, like a "1", or even a decimal point figure. I'm always reluctant to use zeros like this, and in some cases may actually default to no action. Just something to try..

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dunnp avatar image
dunnp answered ·

I suggest using the VS option above - ie "Ignore AC input: VS on = ignore, VS off = do not ignore". That worked on my MultiPlus. I didn't try the "Dedicated ignore AC input" so unsure how it is supposed to work. Phil

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Richard Pearce avatar image
Richard Pearce answered ·

Hi, @Alexandra

I have a similar issue with a Quattro setup on a LiFePo4 battery with Grid connection on AC In 2 and standby generator on AC In 1. I also have 2 signal BMS assistant and utilising DVCC External control direct from the battery BMS (123 Smart BMS)

I also have a Cerbo and Smart Solar dual MPPT. This is grid connected but not set as ESS as I have no plans at present to feed-in.

Within the Cerbo (via Remote Console), I have enabled generator control for the actual standby generator and I have recently setup the Assistant in the Quattro to ignore AC in 2 dependent on SoC (default values for now of 30% start and 80% stop), load and to stop if AC1 is available (so if the generator starts on a timed monthly run up, its output is utilised charging the battery). The General Flag Relay control is set to 'open to start generator' (as it wasn't ignoring AC2 at all when set the other way. Brain got a bit fried with all the double negative implications).

The system is newly connected and this morning the battery fell below 30% and the grid didn't kick in (AC in 2 was not un-ignored). I'm trying to figure out why this is. Is it because i'm also using the Cerbo to start the generator proper via the Cerbo Relay 1 and there's a conflict? Is it because i'm asking it to stop the generator (Grid) if AC1 (Generator proper) is available?

Any thoughts gratefully received.

Regards

Richard

Incidentally, I'm really liking the controls section that opens up in the VRM Dashboard, especially the generator controls, excellent work Victron techs. As a separate item to the above, can i request a second generator control please to either control Relay 2 on the cerbo (and thence via wired pair to an input on the Quattro) or (better still) the General Flag relay as AC Ignore. Can i also request naming options for the second and the trackers on the Smart Solar (to be able to label the arrays).

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Alexandra avatar image Alexandra ♦ commented ·

The smart solars unless you have the RS do not have separate trackers. You have to name the mppts then.

AC 1 is always a priority over 2. If there is any voltage present on ac in 1 ac2 gets ignored

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Richard Pearce avatar image Richard Pearce Alexandra ♦ commented ·

Thank you @Alexandra It is the Smart Solar MPPT RS 450/100.


AC1 is connected directly to the generator. With the generator at a standstill there should be no voltage at all on AC1.

As you say AC1 has priority, I have no need to include the 'Stop generator when AC1 available'. Ill remove this and see what happens.

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Richard Pearce avatar image Richard Pearce Richard Pearce commented ·

I removed the 'Stop generator when AC1 available' and there is no change.

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Richard Pearce avatar image Richard Pearce Richard Pearce commented ·
I've now ditched the generator start/stop and set the programmable relay instead, one for on and one for off. This seems to be the opposite way round to what one would expect. ie. when set to on the general flag ignores AC. In actual fact, it seems to be that when on the AC is on (not ignored) and when off the AC is off (Ignored). So far i have proven this as working by increasing the load past the setpoint and the AC cuts in after the 5 second delay i have set and drops out after the 60 second delay, so all good there.

I'll now need to wait for the battery voltage to drop and hope the AC kicks in.

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chrichri avatar image
chrichri answered ·

Hi, I would not use VS but assistants and there you can set the charge current to 0 in case you would like to pass through (not ignore AC input).

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Richard Pearce avatar image
Richard Pearce answered ·

@chrichri Thanks but if you're referring to my query, I have used assistants as I have the two signal BMS assistant and therefore am prohibited from using Virtual Switch. I would generally agree that the Assistants seem better.

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Richard Pearce avatar image
Richard Pearce answered ·

This seems to be resolved. I noticed that adding the battery state reporting from the Quattro onto the VRM dashboard showed that SoC was always at 100% so i suppose basing the switching on SoC was only seeing this 100%. I therefore changed to battery voltage for the switching and that has now worked successfully. The input current limit is useful to be able to control the rate at which the grid is used to feed the loads and charge the battery as it allows for the sun to come up and take on the loads and charging rather than set an arbitrary switch off value (which is necessary) and run the grid at full speed to get there when its a short time over discharge and waiting a little can allow the sun to take the reins.

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Alexandra avatar image Alexandra ♦ commented ·

@Richard Pearce

Realised i could have suggested an easier way.

Wire up the relay on the GX to the temp input (set the temp inout to drive the primary relay on and off conditions). Use the generator start stop function from the GX to connect to grid based on conditions and then a manual override it possible.as well.

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Richard Pearce avatar image Richard Pearce Alexandra ♦ commented ·
Ah, thank you @Alexandra , my bad, I didn't make it clear that I'm already using the Generator Start Stop feature in the GX to start the actual diesel generator. I really like this feature with the controls available on the desktop. It would be great if Victron could duplicate this feature so it could be used for the second AC In on the quattro. I think also, as I'm using the 2 signal BMS assistant, I'm not sure if I could also use the Temp input to drive the primary input relay BUT I could interrupt the wiring from the BMS Charge relay into the input I've chosen in the Quattro. Would this interrupt the AC in or simply prevent the battery from charging while allowing the grid to 'passthru'? I think charging only would be interrupted (working from memory).
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Richard Pearce avatar image
Richard Pearce answered ·

@Alexandra Well I thought I had this sorted until today with very low sun and a battery discharging approaching my grid cut-in point of 51.2v for 10 seconds. This came and went as I watched the battery discharge below this and no response from the Quattro. I thought I witnessed this working when I first tested it, but now I'm beginning to doubt myself. It certainly switches the grid on when the load goes above 6688w for 10 seconds and cuts the grid off when the load gets below 2000w for 60 seconds, this is easy to prove. The only way i can prove the ignore AC by battery voltage is to set a level and wait.

The other thing I keep getting is a warning on the VRM Dashboard pop up saying "Warning-Realtime connection disabled due to GX Device Overload" which I am now seeing on and off with no real reason that I can see other than it seeming to show more when the battery is below 51.2v. The Cerbo shares a fairly tight control box with relays and AC cabling close by. I've been unsure if this was going to cause any EMC related issues but couldn't find anything that would indicate it being susceptible.

Again, any thoughts why these might be happening gratefully received.

Not sure if this is significant but last night we had a thunderstorm. The nearest strike was 1/2 mile away and I have a ground rod at the generator and surge protection both on the grid connection and on the output from the Quattro down at the house end (about 30 metres cable away).

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Alexandra avatar image Alexandra ♦ commented ·

@Brian Brown

Sometimes the interference cause by lightning strikes messes with the brains in the inverters and mppts.

There have been a few odd posts around and where even the bootloader sequence was triggered. But a VE bus restart cleared things up.

Have you tried programming the ac ignore using victron connect and the mk3?

The GX overload may be a vrm upload thing. How reliable is the logging?

Your other option is to try ignore ac using the generator assistant.

I was thinking it might be possible that the 51v set and the 25% soc may not always correspond in your system. So it would prioritise one over the other. It is really simple logic there.

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Richard Pearce avatar image
Richard Pearce answered ·

Thank you @Alexandra, when you say a 'VE Bus restart' do you mean to cycle the power on the VE Bus product, in this case the Quattro? I did a reboot on the Cerbo but tis made no difference.

I've not used the MK3 as I've always had a good experience with the Remote VE Config via the VRM.

The VRM logging seems spot on It is just throwing this warning and stopping the real time view every so often. Its the only system I've seen it on and its not overly complex. One thing i do suspect is the non-isolated tank sender for the fuel. One side is tied to ground which is also earthed and is B-12v connected to the ground side of the Cerbo digital input. I've now resolved to isolate this ground connection to at least eliminate it.

I did try the generator assistant early on and had it not bring on the grid. I might revisit this as I think at the time it was looking at SoC rather than at battery voltage from the BMS.

You are spot on, the battery voltage and SoC don't correspond. The 51.2 seems to equate to 0% probably due to be setting the battery capacity at 80% of its true capacity. I may change this to better correspond.

I'm beginning to think that ESS may be the better way to go but will give the ignore AC another test with the voltage up a bit so I don't have a panic on with the battery getting too low.

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Richard Pearce avatar image
Richard Pearce answered ·

I set the relay to cut the grid in at below 52.2v and back out again at 53.1v and all worked well.

@Alexandra Curious to know if a VE Bus Restart can be initiated automatically or at least with one of the inputs that could maybe be linked to relay 2 on the Cerbo.

I notice a VRM update this morning. We will se if this stops the 'Cerbo overload' warnings.

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Alexandra avatar image Alexandra ♦ commented ·
@Richard Pearce

Sorry, i saw your earlier reply and didn't get back to you.

A ve bus restart theoretically can be done with a relay (i haven't tried). There is on some models a physical switch that can be wired up. The other way is node red.

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Richard Pearce avatar image
Richard Pearce answered ·

Hi again @Alexandra, I'm still experiencing issues with the Quattro not cutting in the grid. It seems to work when I first set it up but fail at some point thereafter.

I am using a third party BMS on DVCC but have not had any issues since re-routing the USB cable (it was causing the whole system to black out due to EMI issues) and adding some ferrite common mode filters. I can only think this would simply shut the whole system down if there was a disconnection or data loss between the BMS and the Cerbo (like it has done twice before addressing the EMI issues) rather than just interrupt the Quattro's tracking of voltage (which continues to be displayed on the VRM ok).

I should also say this Quattro has been back to a Victron repair facility for accidental contact with the Aux terminals to the battery and returned repaired.

If there's any way of looking to see if there a data interruption or a fault log id be grateful to know.

Thanks as always.

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Alexandra avatar image Alexandra ♦ commented ·
A data interrupt between the bms and system? That would log as an error 67.


Not connecting to the grid can be a few reasons.

Is it not even closing the contact?

Usually there is a louder hum before you hear the relay latch. Is the system doing that at all?

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Richard Pearce avatar image Richard Pearce Alexandra ♦ commented ·

I know the sound you mean, however, though not present at the exact time of switchover, at time after, when the Quattro should be connected and charging, there is no increase in sound. The Quattro is silent apart from inverting sounds varying with load. AC1 is available to connect to but the Quattro hasn't connected. If the load goes over the loading setpoint then the Quattro connects to the grid and disconnects when it reaches the upper limit. For this part if the 'ignore AC' it behaves impeccably.


If we get another battery depletion exercise occur, ill try and be alongside the Quattro at the point where it goes below the low setpoint and see if it tries connecting or there is any sound change or contactor clunk.

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Related Resources

Additional resources still need to be added for this topic

VE Configure/Virtual Switch

Ignore AC input using the Generator Assistant