question

mysik avatar image

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:

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:

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:

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

Multiplus-IIESSgridct
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11 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Mysik and others,

I've asked around, and this is a known issue that is being worked on.

Thanks for finding and reporting the issue!

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Hi,

Additional to the occuring slow response I'm adding a Video of (relative) stable Loads but somewhat "confusing" fluctuation of grid setpoint:
My settings: Grid setpoint -20 -> Please note that I dont have AC Loads connected. The whole house is on Critical loads. therefore AC Loads should stay on zero.

regards
Andy

grid.mp4 (1.6 MiB)

Any progress on this? I'm facing a similar issue, which might be related to ESS + ET112, where it is back-feeding into my grid and causing the prepaid electricity meter to reset. @Daniël Boekel (Victron Energy Staff)

Are you on one of the tshwane newer smart meters? They are very sensitive and have been causing issues.

Double check what your grid setpoint is in ESS, raising this can help.

Make sure grid feed-in is disabled.

No, I have a 12+ yr old Conlog BEC23 prepaid meter, in George. It allows 40W for 15s or 600W over 1s of back-feed before it will cut-off the grid, which sounds reasonable to me, not very sensitive. The Victron is responding very slowly to load changes, and often feeds in over 500W (I've seen up to 1800W) over multiple seconds (as many as 15) after a load such as a kettle is switched off.

My default grid set point was 50W, but I've tried raising it to as high as 300W, and it still doesn't solve the problem, meanwhile causing loss of efficiency of the ESS. Grid feed-in is disabled.

copy of answer in other topic:


for faster response: have the loads behind the inverters, this gives a faster response than with the energy meter.

having the energy meter as source works for 99% of customers, but in this mode all kinds of grid rules have to be followed also (that's one of the reasons it's difficult to improve the reaction time), when loads are behind inverter ('critical loads'), the inverter can provide power almost instantly.

gyrovague avatar image gyrovague Daniël Boekel (Victron Energy Staff) ♦♦ ·

I'm not sure I follow 100% what you're suggesting. Are you saying that the non-essential loads should all be moved to essential? Problem with that is (I think) then if there is grid failure, those loads could un-desirably use up battery energy unexpectedly (oven, stove, geyser etc.).

From the other thread, I am not sure why you have a grid meter. Your setup does not need one, I asked if this could be affecting response times. Perhaps @Daniël Boekel (Victron Energy Staff) can answer if it is an idea to remove/bypass it and if that could help?

Maybe, I'm not sure. The grid meter has been disabled now in the ESS configuration, but it made absolutely no difference, the inverter response to loads changing (in both directions) is still very slow.


Edit: see here my other post (which was diverted to this thread), where there is some more info about my setup and the issues: https://community.victronenergy.com/questions/61374/victron-ess-slow-response-to-load-changes.html

You could move them behind AC-output 2 and cause that to fail during a grid failure

Oh, I was actually under the impression that is how it already is... but, looking at the installation line-diagram now, I see that it's not, the non-essential seems to be connected to the municipal side after the energy meter but before the inverter.

It's not unusual to do that, in a solar setup you'd really want to attach appliances that you want powered by solar or battery. The rest leave off the inverter.

n-dee avatar image n-dee Daniël Boekel (Victron Energy Staff) ♦♦ ·

Don't know if I understand you - but I have everything behind the inverters (only critical loads) and it is not faster than before. (well smartmeter is there aswell)

regards,

Andreas

My solar installer is saying the same or similar -- he says they actually had worse overshoots when using AC2 on previous installations with multiplus II and quattro, and that having non-essential before the inverter with grid meter worked far better :shrug:


Unfortunately in my case it will require significant and costly rewiring to move the non-essential to AC2, so it's not a quick and easy experiment at all. I would need to jump and commit to it, and if it doesn't work out (as installer predicts) then I've wasted even more money. It's 50m of extra wiring (thick expensive cables too) and multiple hours of electrician labor, so not cheap.


I'm at somewhat of an impasse it seems. The municipality blames the victron ESS system, so they won't replace my prepaid meter (and they have an exclusivity deal with Conlog anyway). The installer says the Conlog prepaid meter is too sensitive (though the Conlog spec allows 40W/s over 15s or 600W in one second, which supposedly conforms to some standard and sounds quite reasonable to me), and I need to replace it with L&G, but I can only replace it privately with a 4-quadrant L&G, but at great cost (around 400euro, imported from Europe, because the locally South African manufactured ones apparently require some power-line comms grid infrastructure which my town does not have). If I have the system rewired so that non-essential is on AC2, it will cost less than a new prepaid meter (but far from nothing), but it very well might not solve the problem (dead loss if so). If I don't do anything, I cannot use my oven at all (as has been the case the past few weeks since the system was installed). From my point of view, I agree with the municipality, that the Victron ESS overshooting hundreds of Watts for 10-20 seconds is unacceptable and causing the prepaid meter to disconnect the grid pro-actively. If Victron @Daniël Boekel (Victron Energy Staff) can give me more assurance that rewiring to AC2 is the correct solution, I can go that way.

HI

I have two observations/suggestions may somebody can comment on or weigh in on. Would either of these be viable. The first is something for Victron and the second a wiring question.

1) According to the technical spec the ET112 has a maximum response time of 500ms. If Victron adopted another meter with a faster response time they could change this. The Fronius grid meter (Victron have a relationship with Fronius) samples at less than 200ms. My logic is a faster sampling rate would slightly reduce the peak and significantly reduce the duration of the feedback. I was wondering if Victron could not change their software to support the Fronius 63A-1 meter (It also has a Modbus/RS-458 interface. I know that not all meters return the same measurement data and that this isn't as simple as wiring up a new meter) @Daniël Boekel (Victron Energy Staff) would this be a possibility?


2) Could you not rewire your setup as follows (Is this legal and or possible) and would it work

Present wiring:


Proposed wiring


I realize this will proably mean you don't get any benefit of solar for your oven, and its usage wont be part of you reporting. Would it work?


Any thoughts?



grid-par.png (13.3 KiB)

Just put a temporary equivalent load anywhere convenient on the AC2 output and test the response before committing to the expense of permanent measures.

Hi, the easiest and cheapest way to test the AC2 will be using 1 or 2 grill / micro-wave owens, so you can install them easily near your AC2, and having them sucking around 2kW ...

You can borrow them from your neighbors, just for a few hours, during your tests. No costs, no cabling, and a result.

Michel

Great ideas @Phil Gavin and @MichelG, thanks! I have some electric oil fin heaters than can draw 2kW on demand, pretty similar to what the oven on non-essentials currently uses.

Yesterday I removed the smartmeter and configured cerbo in -> ESS -> grid metering to Inverter/Charger.

The speed on load-changes is MUCH (!) better. Only two or three seconds.

regards, Andy

Any news on this?

regards, Andy


@Daniël Boekel (Victron Energy Staff) is there an update on this ? Why is there a difference between the reaction of a CT vs Energy Meter ? It seems it's not the communication and it's ESS how acts differently, in my head it's just a different way to give the same information to the system.

Rob Duthie avatar image
Rob Duthie answered ·

Hi

Remember a CT is a analog device and will be much faster in doing calculations than a digital meter like the ET112 which does have built in delays in the baud rate and in its sending of data out

which can be set in the ET112 configuration software you can set baud rate and DMD calculation time etc to upload the data.

Note: the ET112 is way more accurate (Meter Grade Quality) in measuring values than the CT is, the CT is only average readings, as advised by Victron. And they advise the setting of the grid set points should be greater than -10 around about -50 or +50 as the inverters are not revenue grade type readings as a Fronius inverters etc which are. Standard setting is 50. If read the ESS manual guide it tell you this.

I have the same setup running all the latest firmware updates (need to check yours?) which has a lot of improvements regards to readings in power etc. And i have not noticed any lack of speed of the readings which appears to be around a second. I have mine set to zero grid set point, which works OK in my application.

And i have zero feed in and all export when i have surplus PV power. Also mine is running over a wireless RS485 link as well.

Regards

Rob D

NZ

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If I can see a load measurements that I have on the GX screen are from ET112, so the system knows that there is a change in the load, it is just not reacting fast enough.

It pretty much looks like ET112 is sending data to VenuxGX, but Multi is lagging behind. So from what I can see the problem is more in VenuxGX or/and Multiplus settings or comms between them. If ET112 would be a problem then you would not see the load on the VenuxGX screen and that is not the case.

I can confirm the behaviour. When I switch on the 2000W load, the correct measurements of the load and the grid usage (from ET340) are shown on the Remote Console after about 2-3 seconds. BUT it takes another 10 seconds until the ESS regulation has compensated this load to the grid setpoint.

Maybe the quite slow regulation speed is intended this way?

Maybe @mvader from Victron can bring some light into this?


Regards

Rainer

Hi, contacted mvader already with this some time ago. (but not as prezise as you do)
Answer was that it is not (and willl not be) worked on this.
I hope that with more people reporting he will change his mind.

peternielsen avatar image
peternielsen answered ·

@Mysik @RainerB did you find a solution to this, what is the reason one cannot use CT sensor on each grid phase ? Is there a benefit using the Energy Meter, i can see you @Mysik changed from CT-> Energy meter, why ? Can ESS not work with 3 x CT sensors and do the same as an Energy Meter ?

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Hi, unfortunately I did not find a solution for this. I am still using my ET340 energy meter and it is still slow.


Regards

Rainer


Rob Duthie avatar image
Rob Duthie answered ·

Hi All

I am running a ET112 with Mulitplus2 and Fronius Grid tied inverter and 10 kw Pylon tech battery pack, and my ET is wireless linked to the Meter board to my raspi controller, and i have no issues of slow response at all. I have set my feed to zero feed for the Victron but the Fronius injects what it likes etc. But the meter response is very quick in flipping from supply load and battery and grid within a couple of seconds, no delays anywhere at all.

But being in New Zealand we don't have silly lines, or power retailers company's restricting or penalizing you for injecting power like other countries do. You need to protest your rights to the solar movement. They are are being a bully boy.

Rob D

NZ

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matthias-roetzer avatar image
matthias-roetzer answered ·

Hi all,

I've seen this slow response to load and PV inverter output jumps as well in cases where the multiplus II does the grid measurement. I was then curious how it would behave in off grid mode and good thanks in this case the response is ultra fast.

@Daniël Boekel (Victron Energy Staff), nevertheless this is a nasty issue, glad to hear that Victron is working on it!

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jacola avatar image
jacola answered ·

is there maybe a way to simulate the CT Sensor, to take advantage of the much faster response handling ? I guess the "correct" way would be that victron addresses this in the software, but i am willing to read my meter, do my own control loop and provide split second setpoints, even by simulating a CT sensor, as long as the multiplus follows my wishes quickly ..

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jacola avatar image
jacola answered ·

Same problem here but with a "twist". I have an ET340 and poll it from an ethernet based linux controller approx. 5 times per second. ESS IN "EXTERNAL" mode, i want to control it via setpoints.
Ialso read the relevant modbus registers showing the actual production values for the multiplusses from the venus GX approx 5 times per second.
I calculate the needed setpoints with those 200ms intervals, so i could update the setpoints via modbus/tcp 5x per second, but the system then behaves very erratic and sometimes even the AC load side is not showing on the display any more.

So now i have reduced polling and setpoint calculation and setting (via mb/tcp) to about once every 1.2 seconds. i can see that despite writing back those setpoints every 1.2 seconds via mb/tcp, they freqently are ignored/dropped (but modbus write is acknowleddged) ! maybe that gives a hint.


ESS 1: -44/ -160/ -230 2: -24/ -804/ -801 3: -33/ -684/ -641 BAT: 69.0,49.8new setpoints should be -146,-811,-682

ESS 1: -62/ -160/ -146 2: -31/ -804/ -801 3: -28/ -684/ -641 BAT: 69.0,49.8new setpoints should be -128,-804,-686

ESS 1: -54/ -160/ -128 2: -27/ -804/ -804 3: -28/ -684/ -686 BAT: 69.0,49.8new setpoints should be -136,-807,-687

ESS 1: -48/ -160/ -136 2: -32/ -804/ -807 3: -36/ -684/ -687 BAT: 69.0,49.8new setpoints should be -142,-802,-679

ESS 1: -28/ -160/ -136 2: -24/ -804/ -802 3: -42/ -684/ -687 BAT: 69.0,49.8new setpoints should be -162,-810,-672

ESS 1: -21/ -177/ -162 2: -25/ -812/ -810 3: -49/ -663/ -672 BAT: 69.0,49.8new setpoints should be -187,-818,-645

ESS 1: -5/ -177/ -187 2: 2/ -812/ -810 3: -25/ -663/ -672 BAT: 69.0,49.8new setpoints should be -203,-844,-668

ESS 1: -1/ -177/ -203 2: -13/ -812/ -844 3: -23/ -663/ -668 BAT: 69.0,49.8new setpoints should be -206,-829,-670

ESS 1: -10/ -177/ -203 2: -29/ -812/ -844 3: -28/ -663/ -670 BAT: 69.0,49.8new setpoints should be -197,-813,-665

I have high power pumps (11kwh 3P), when they come up they run for several seconds and then switch off. This causes complete instability of the victron stuff, said simple - it cannot follow at all and usually i have to feed the pumps for many seconds from the grid, then when multiplusses finally are up to produce, the pumps switch off and i feed the grid.

I would be more than happy to see this getting fixed. Maybe those observations help - i guess it's not the ESS regulation or meter speed (because both is not having an influence here in my system), it seems to be loss of set setpoint values, eventually, and very slow responses from the multiplusses to GX

Johannes


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christian-dorst avatar image
christian-dorst answered ·

I have the same problem with EM24 in 3-phase-setup with Multiplus II here.

https://community.victronenergy.com/questions/54038/multiplus-ii-ess-mode-1-latency-and-limits.html

Sunny greetings

Christian

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n-dee avatar image
n-dee answered ·

Same Problem here (with EM24) - System needs approx 10 seconds to compensate

Additionally:
1) Grid setpoint is never reached (regardless of setting) but fluctuates around setting.
2) Fluctuation of setpoint is as high as +-1500watts (if load kicks in) so that even water warming (set to -500w) kicks in (after load ends and ESS goes to e.g -1000w) and drains battery.
3) In Austria feed in from Battery in the night is actually forbidden but due to the points above this is not configurable.

Seems as ESS function is technically not mature. I'm hoping for improvements in future firmware releases.


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hello,


please see attached picture with reaction time in a ESS system.


laurentiu

answering-time.png (107.6 KiB)

But ESS function with CT clip looks muuuuch better than when it using grid meter. That what I still don't understand, especially that using grid meter you have more accurate information and this data is available on GX device because it is displayed, it just look like the system is not using it or is poorly tuned to use it.

rainerb avatar image
rainerb answered ·

Hi,

I have a Multiplus with ET340 meter and my ESS system needs about 15 seconds to compensate a 2000W load. Is this a normal time span or can I increase the speed?

What is the recommended baud rate for a ET340 with about 5 meter cable length?

Thank you.


Regards

Rainer


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stxshadow avatar image
stxshadow answered ·

This looks exactly like my system with an ET340 System. I even did not know that i can respond fast with a CT Sensor. Do you know if 3 Phase setups are possbile with the CT Sensor ? It would be a very nice option for me then.

Thx

Jens

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