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ET112 + Current Transformer - AC Loads reading

It's been a known fact that ESS system with ET112 as grid meter is responding very slowly to high load change and that the same system with CT clip is responding much quicker.

On the other hand ET112 is much more accurate in terms of energy usage calculations.

I thought it will make perfect sense to use both... CT to get fast responds and ET112 to get accurate grid usage readings. So I've wired up my system like on the diagram below:

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I've noticed that after connecting CT to Multi I'm getting fast responds to load as expected but, on the VenuxGX diagram my AC Loads has not been calculated correctly (the actual load is about 800W), the meter settings is set to Settings-->ESS-->Grid Metering-->External Meter

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Correct diagram, but AC Loads inaccurate

So to get accurate AC Loads readings I had to set Settings-->ESS-->Grid Metering-->Inverter/Charger, and now I'm getting accurate readings on the AC Loads, but the diagram is incorrect:

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AC Loads correct, but wrong diagram

Is there a way to use both ET112 and CT clip and set this up to show correct diagram with correct AC Loads readings?

mysik asked
mysik commented ·

3 Answers

Victron ESS + ET112 = slow response

Hi,

Recently I've installed ET112 grid meter on my system (which was using CT sensor previously) and I've noticed that the Multi is very slow on response to load. Currently my system looks like this:

[image]

The grid set point is set to -10W. The multi needs a good 15-18 seconds to stabilize after large load kicks in and another approx 15s to stabilize after load drops off. Check the video from VenusGX (the load is switched on at about 16s of the clip and switched of at 43s of the clip):

Is that how it should be? The difference in the load is just about 1.4kW, why is it taking so long to handle that?

Previously I was using CT Sensor extended with Cat5e cable to over 25m long, the system looked like this:

[image]

The response to load was pretty much instant. I've recorder video using the same load as on the previous one (load switched on at about 10s and switched off at 23s of the video):

The system need seconds to stabilize

Also you can see a clear difference on the Grid use graph from VRM portal:

[image]

[image]

As you can see, with CT sensor the system is very close to grid set point, with ET112 grid meter it is way off and hardly ever stay close to set point. The situation is even worst during cloudy day when PV power is fluctuating (you cen see it on my other youtube video).

Is it normal behavior? It looks like Multi can handle this load easily, the problem seems to be in the feedback from the grid meter (or algorithm when ET112 is in use). Is there anything I can do to improve this reaction time??? Please advice.

Kind Regards

mysik asked
Maciek commented ·

13 Answers

Wiring for ESS

I've read through all the ESS documentation and wiring diagrams and read everything in the forum and watched several training videos about ESS and wiring for ESS and still have some questions, hopefully you all can help me get things sorted out!

When running ESS with no grid feed option and prioritizing PV to run essential loads (AC OUT 1) is a current transformer needed and what is the best method for isolating the essential loads?

Currently, all the loads are in one service panel before the inverter. I have divided the panel so my critical loads are on one side and non-critical loads are on the other side. I have a breaker interlock on the breaker receiving the AC OUT from the inverter and manually throw it when I need to power the side of the panel with critical loads, which is 120V as I am using a 120V Multi. Essentially, its more-or-less a combination of a UPS system and backup system intended for rare grid failure, but I want to use ESS to export as much PV as possible to reduce the Grid AC loads during the day (and charge the batteries.) Generally the system will use Grid AC at night and only use battery consumption when no Grid AC is available limited to a 50% SOC. My current configuration/setup is obviously not an optimal situation as I am not setup to back-feed the grid and have no intention to do so, but currently this 'manual' procedure is what I am doing until I better understand ESS and wiring for it.

When designing for ESS, is it appropriate to move all the critical loads out of the main service panel into its own subpanel and leave the non-critical loads in the main panel and/or should I be utilizing a current transformer? Also, is there a reason to use AC OUT 2 at this point, if the non-critical loads remain in the main service panel, as they don't 'need' to be utilized when Grid AC is not present. However, I would like the option to still use non-critical loads. Therefore, are ALL the loads supposed to be after the inverter on AC 1 and AC 2?

Is it best to have two dedicated breaker panels, one for critical loads (AC1) and one for non critical loads (AC2) and just use the main service panel as a distribution point for the Grid AC and the placement of the current transformer. Trying to understand the best configuration taking into account the ESS and Multi's capabilities. Below are several threads I've posted relating to this subject. Thanks in advance for an insights or suggestions and thank you to those who have already commented in previous posts, I look forward to your suggestions.

Schematic below

[image]


How do I setup ESS setup for PV priority

Automatic transfer switch

How does Multiplus II w/Cerbo ESS prevent AC backfeeding?


duswami asked
lifeingalicia answered ·

5 Answers

Multiplus new CT brought and added however still not charging batterys

Hi I have a multiplus 5000va ive had this system installed by an electrical contractor for the past 6 years. Until recently I had no problems. its the old Carlo Gavazzi meter with the three terminals on the bottom for monitoring via the mbus usb cable. What happens is it constantly dropped pv inverter from the ccgx. So I tried everything which failed, brought a new CT sensor wired it in today and the pv is back. however it still does not appear to be charging my batteries from the sun.


I will test this further tomorrow but any ideas what's happening?

Dale asked
Dale answered ·

2 Answers

Can I extend the CT clamp wiring

My installation of the MP is some distance away from the incoming supply and being a grid parallel ESS installation I need to install the CT clamp in the incoming supply I have a cat 5 cable installed between the two locations, can I extend the wiring on the CT clamp?

elliot330 asked
elliot330 commented ·

2 Answers

VRM & remote console - PV CT sensor data disappearing & reappearing after a GX reboot

Another issue now, the PV generation data on the VRM portal & the PV 40A addition in the remote console keeps disappearing in both. The only way to get it to come back is to reboot the Multiplus in the remote console (GX side) and wait for it to reappear, only for it to disappear again an hour or so later. One day I might have a fully working system as expected. Please see the below video.

https://youtu.be/a0QXKCuvZn4

Jason - UK asked
Jason - UK answered ·

1 Answer

Multiplus 2 5kVa 48v GX, issue with AUX1 with CT sensor & ESS - Round 4

So I have been going round in circles with this issue from shortly after I got my Multipllus II GX 5kVa 48v unit. I connected a CT sensor to AUX1 as per the Victron instructions, set the dip switches to 1,2,3, set the CT sensor in the assistant in VE configure 3 as per my arrangement with PV on AC1 out and set it to AUX1, as how I had connected it. All was fine for the few hours before the option to download the Remote VEConfigure files had disappeared from the VRM portal. Found some info about how a firmware update was required, which I did and form that moment ESS stopped working.

After 2 days and 3 posts on this Victron Community page, @Rob Duthie came to may aid and between us, we worked out that it was the sensor was the issue. I has assumed that after the firmware update it had removed all assistants, that stopped the CT sensor form working correctly after the firmware update. I unplugged the CT sensor form the AUX1 and ESS started working again. Brilliant, I thought we knew what the issue is and I'll fix another day.

I ordered another 40A CT sensor assuming the sensor was damaged or I did something to it to prevent it from working correctly, reconnected it to AUX 1 as per the instructions, set up the current sensor in the VE Configure 3 app, uploaded the file and then restarted the system, but again ESS stops working.

Maybe I am missing something but if I have following the instructions to the word, can some one help me and shed some light on why ESS is not working when I connect the 40A Victron CT sensor to either AUX1 or AUX2? Am I doing something wrong?

I have now connected the sensor to AUX2, of which I still have no reading for the PV input as I did before the firmware update but at least ESS is working. Could I potentially have a faulty unit? 2 weeks of having this unit running and a 50% down time, I am quickly losing faith.

[image]

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The reason for not not trying AUX 2 previously as first I did not know the issue was with the Multiplus II GX unit and also I had other uses for AUX2 already wired in.

Jason - UK asked
Jason - UK answered ·

1 Answer

PV Inverter output CT compatibility

Good day

I was wondering if it would be possible to use a generic CT on the output of a (non-fronius) PV inverter in an AC coupled ESS system.

I do not mean in conjunction with an energy meter. I mean plugged straight into the Aux input 1/2 plug in the Victron Multi/Quattro inverter. Obviously you would have to change the CT ratio in software (whereas with the victron CT you can do that with DIP switches) and you might lose some resolution depending on the ratio of the CT, but ultimately it should be doable, no?

Is my thinking flawed?

Look forward to hearing your answers!

-HB

hanno-bisschoff asked

0 Answers

Current Transformer for MulitPlus II - can the cable be extended and what is the maximum cable run?

If I implement the Current Transformer (CT) recommended for the MulitPlus 2 and install it at the Grid interface point. What is the maximum cable distance?

I looked up the specification for the Current Transformer YHDC.com SCT013 100A:50ma shows this CT model is terminated at the measuring interface in a 10-ohm resistor to achieve a 1% accuracy. Another poster measured the MulitPlus 2 input resistance at 40ohms, I'm yet to confirm this.

With such a low impedance required for the CT would indicate the wiring Extention could be very limiting or the cable size (mm2) would need to be increased.

What is the recommended loop resistance of the CT wiring to keep the calibration of the CT in the Victron implementation?

Can the CT be calibrated in software?

Or has anyone else successfully increased the CT wiring over any distance?

Thanks in advance for any info.

raymiller asked
raymiller commented ·

1 Answer

Cytrix-ct 120 never disconnects.
Hello,

quick question about a cytrix-ct 120 on my t5 from 2012. Yes it’s supposed to be euro 5 and not working but considering the alternator is sending 14v all the time, I don’t think it’s euro 5.
The - from both batteries are linked together.

The + goes through the ct and a fuse. It was closed all the time so I thought it was broken and bought a new one. I changed it yesterday and didn’t started the van, so no alternator/euro5 questions. 5 min after I mounted it, it closed again, I discovered that with a solar panel or charger on the 2nd battery side, it closes to charge both batteries.

My problem is that it doesn’t open after that, when the dark comes or when I disconnect the charger, my 2nd battery empties in the 1st one.

It is supposed to cut after 3 min after being under 12,8v but it never happens. This morning I was at 12,6 on both sides.

What could I do ?

Thanks.



yopyop64 asked
yopyop64 commented ·

2 Answers

Multiplus-II + ET112 + Current Transformer

Hi

I have recently switched from the CT to the ET112 and noticed something odd

I have a Multiplus-II 3kva + ESS + 140Ah 48v Li-Ion + Batrium BMS (CAN-Bus) + Cerbo GX + PV on ACin

Everything is working fine expect I have noted the following oddity

I was uing the CT and could see the MP2 quickly adjusting to the PV lows and spikes during cloud movment and demands on the ACin during normal operation mode, but since switching to the ET112 I was able to see the MP2 is now really very slow at adjusting the inverter power output and charging, so much so that I can see 1.8Kw export happening from the battery when the sun comes out for 5+ seconds and importing while charging due to the cloud covering up the sun, this is very odd becasue with the CT it was super quick to change and keep the grid at Zero import or export.

I think because the metering has been moved to the Cerbo GX this now has to tell the MP2 to adjust I just wasnt expecting it to be so poor at controlling it with such a slow delay

Everything is working fine just really slow, I'm not runnign anything extera or doing anything extra with the cerbo gx, it is however in superuser mode running v2.52 (came out the same day the cable arrived to pulg in the ET112 so unsure if its a v2.52 related or just expected behavoiur) and i have node red connected to it, no perf issues though and only 1 flow (your charge at night flow) connected to it. Top is not showing any processes that would slow this device down.

Is this expected behaviour when using a ET112 or any Grid meter?

Regards

Mark Boys

Noisy Boysie asked
jgd-ess commented ·

2 Answers

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