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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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9 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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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.

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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