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cocodanila avatar image
cocodanila asked

Excessive noise while charging via new Multiplus-II 48/5000/70

Hello community,

I am running a 3xMultiplus II 48/5000/70 configuration, monophase, all 3 in parallel, all on latest version 508 but the issue was also in 506 etc. I am running dynamic ESS, but was manifesting in simple ESS as well

Symptoms are similar as in this post https://community.victronenergy.com/questions/139719/multiplus-ii-quattro-ii-noise-vs-original-multiplu.html?childToView=141060#comment-141060.

What I have notice it is happening mostly in the morning when solar power is in the area of 3-4 times the load and equal with my setting of pushing into the grid (2-3KW of power). Out of the blue (but some how in sync with sudden change in output or in solar power) even enough power in the battery to feed the grid and the load, the inverter start pulling from the grid and start charging the battery and the load with 2-3KW, and making that horrible noise. The status of invertor is flicking from bulk to passthrough and back and registering a message of overcharge. If you put the system in inverter mode is stabilize back. I've notice sometime, if changing grid setpoint might stop the noise and stabilize the system, but this is not working all the time.

I was wondering if someone else has the same issue?

PS: yes same cable length on input and output, but no change!!


Multiplus-IImultiplus in parallelseplos
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Alexandra avatar image Alexandra ♦ commented ·
What batteries do you have. Do they have DVCC control on the system? How full are they when this is happening?
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cocodanila avatar image cocodanila Alexandra ♦ commented ·

Bateries are 3 Seplos on CAN, with Pylontech in between them. DVCC is active now, with current and charging tension limit with sharing all 3 parameters active.

SOC it does not matter I think, same symptom anywhere in between 30% (my bellow ESS limit to 70-80%)

Today, some more info: all went fine at sunrise up till the PV power was close to double the load. I had to keep it on inverter until PV reach 5 times the load. It struggle for a while (like 2-3 minutes) but went quite at the certain time

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Alexandra avatar image Alexandra ♦ cocodanila commented ·

A short note on parrallel setups, they can be temperamental. Experience is needed to get them right. Cable length can be the same but connection resistance can also have an effect. When inverting do all the inverters pull the same amount from the battery an when grid connected share the load equally?

I am going to repeat what is often said and annoys the heck out of people. Since it is not a supported battery instabilities are to be expected.


That being said, are the seplos 15s batteries like the pylontec?

Does this happen at all if feedback is switched off?


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cocodanila avatar image cocodanila Alexandra ♦ commented ·

Tried in the past with only one battery; all the same. If I set them in inverter mode only, this thing do not happen. It is actually the way that I stabilize them, but then in the summer I will not be able to export.

Only one thing I have not tried: if happens with only 2 inverters in parallel!!

I will look for measurement maybe tomorrow, as today we passed the critical point (but because of a very sunny day today, I will store enough not to be fully depleted tomorrow)

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

Again today, I was not at home when happened, but again when PV is near 2-2.5 times the load and coming out of bypass is doing like that. In the graph you can see it struggling for 10 min and then went normal. More and more is looking like a firmware error. How Can I officially report this?


https://betavrm.victronenergy.com/installation/333558/advanced

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Alexandra avatar image Alexandra ♦ cocodanila commented ·

@cocodanila

I can pass it on.

Is it AC coupled PV

Have you tried it with no battery communication with the system. To rule out the interaction there.

It is not an officially supported battery, so that will be the first thing that is pointed at.

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

No, it is DC couple with MPPT RS 450/200

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

And not tried without comms; I had some tentative trouble shooting with local tech representative in Romania but no luck. I am not actually in support to them but maybe because of that is also the lack of interest to find what is the issue. It is really puzzling, BMS is still in control (no change in CCL, CVL) MPPT is still in external control mode. I still believe that has something to do with firmware .... I have seen something similar with and error introduced at 483 solved with 486, but also I might do something stupid as I build the system reading the technical manuals

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Alexandra avatar image Alexandra ♦ cocodanila commented ·
There was another post somewhere on the forum where even if DVCC is forced off the seplos still messes with the inverter and system control.

Remove the BMS cable reset the system to no BMS control and test.

Sorry but with no official support it will take your time and energy to work out.

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

It is working like a breeze with a 2 in parallel configuration!! I had a hunch that the one starting serial HQ2222 might be the issue. I've ordered a replacement and see if is a 3 issue or simply an inverter issue

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

It is not working with a spare, just purchased a new one :(

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cocodanila avatar image cocodanila Alexandra ♦ commented ·

Today, it happen again ; system started with bypass, PV charging the battery until reach something like 2.5 the load. I guess that this is normal, the inverters are doing some calculations/averages before switching into different mode. Then when reach something like 2.5 times the load for a while (I guess like 5 min), it is starting disconnecting the main (Dynamic ESS is off) and I guess some software bug is happening as is starting charging from the main and the PV in the same time, although there is no need from main. I have a strong vibe that instability of the system would be until 5 times the load and then will stabilize. I will let you know, I have to wait 15 min from disconnecting the main (just started again!!!). Meet you at PV 3.5K!!!

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cocodanila avatar image cocodanila cocodanila commented ·

Yes, at 9:40, when connected back to the main, struggle for 30 secs, but then stabilize. Tried to push is over the edge with the load, but stable rock solid. I think we are done for today.

Notice also in the past that the system stabilize more quickly when dynamic ESS is off. IF is it on sales or auto takes sometime, but also I have not invested too much time in study the issue.

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3 Answers
cocodanila avatar image
cocodanila answered ·

Bateries are 3 Seplos on CAN, with Pylontech in between them. DVCC is active now, with current and charging tension limit with sharing all 3 parameters active.

SOC it does not matter I think, same symptom anywhere in between 30% (my bellow ESS limit to 70-80%)

Today, some more info: all went fine at sunrise up till the PV power was close to double the load. I had to keep it on inverter until PV reach 5 times the load. It struggle for a while (like 2-3 minutes) but went quite at the certain time

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manta avatar image
manta answered ·

You cold login to your Seplos battery and lower down the max charge current for each battery, in the range of something like 70A.
Canbus will communicate this with your Multiplus DVCC settings. This would likely solve the issue. At least you can try.

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cocodanila avatar image
cocodanila answered ·

It is already limited from 200 to 100, and on top DVCC is limiting the overall at 250 (for 3). Control now is in Victron, Seplos is doing only the protection part

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