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Paul B avatar image
Paul B asked

Multiplus 48/5000 with PV installed 4.5Kw output hz keeps changing and shutting PV down (Work around Solution found as well) firmware v 433

Hi All

This issue maybe present in earlier firmware versions as well but I have not tested these.

This will only affect you if you have a grid connection and are turning the AC! IN off by using assistants to turn off the AC1 In INPUT , if you are using a generator then I do not think it will affect you as well.

Having some wild Freq/Hz movements every 14 sec 49.9 to 53 Hz

Multiplus 48/5000 230 Volt (firmware 433)

ESS installed

5000 PV grid tie

4500 watt panels

venus GX (Firmware 2.22)

VE BMS

10 Kw battery bank

current SOC under 30% so full amps of 70 is no problems

There should be NO reason that the Hz should be increased to shut the PV down


Assistants installed

ESS

General Flag (Ignor AC on AC1 in) (used so the Venus Genarator autostart can be used)

Program relay (turn AC1 in relay on) (used so the Venus Genarator autostart can be used)

Program relay (Turn AC1 in relay off) (used so the Venus Genarator autostart can be used)

AC Current Sensor connected to AUX 2 (Serial numbers are ok I tied Temp sensor first and it still had same issue so moved to AUX 2)


and the hz fluctuation still occurs 50 to 53 then back to 49.9 then up again every 14 sec (there abouts)


I have tried removing all assistants except ESS and it stopped doing it ( is this a hint)

but the VRM display then showed no AC loads


Further testing

Now have ESS installed and AC current sensor only and its not doing the freq Fluctuations. holding 50hz

have now added back general flag as well

Still no Hz movements (yes AC1 in power is disconnected by mains switch though not by turning ac1 relay off) (still no freq movement) Hmmmmm

Have now added the two relay controls back as well. and now I have found the issue

1. the issue of Frequency moving up to my PV cut off of 53Hz

well this happens when you use the Generator autostart to stop the generator thus in my case OPENING the AC1 IN relay. then the Issue OCCURS the Freq is unstable and moves 50 to 53 hz every 14 sec

CAUSE of issue

Now there is still Voltage on the AC1 IN relay but its turned off in the inverter so no ac in power but the voltage is still THERE and I think the inverter is still trying to sync to that Hz Freq signal

short term solution turn the incoming MAINS off

IF I manually turn all input OFF TO AC1 IN The fault or ISSUE goes away


further update and a fix

move the Assistant General flag to position one and the ess to position 2 and this stops the issue











MultiPlus Quattro Inverter Charger
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2 Answers
Paul B avatar image
Paul B answered ·

Further update and a fix

move the Assistant General flag to position one and the ess to position 2 and this stops the issue

2 comments
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boekel avatar image boekel ♦ commented ·

Interesting find!!

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offgridsolutions avatar image offgridsolutions commented ·
just this exact same problem as had to set up the ignore ac as ESS was still allowing power from the mains when a hair dryer was running, but not with a 9kw shower!!
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assyntdavid avatar image
assyntdavid answered ·

@Paul B you are a star!!

I have been grappling with this for days in an extremely similar situation. I was about to pose a plea for help/explanation on the forum when a slightly different search brought up your post which I had missed. I had found another post from June 2022 regarding a Quatro with unstable mains and generator inputs and PV where Victron Service had said the issue was due to 'frequency shifting' which was done because "As long as some AC input is present, the units keep "getting ready" to connect as soon as voltage is within limits. This means that to prevent overvoltage on the output, the PV inverters are shut down by periodically raising the frequency."

Except this makes no sense when the Ignore AC is a software controlled flag holding out the only possible mains input, and any switching on of the mains is also under software control. So why do this constant frequency shifting process???

I never thought of reordering the Assistants, but yes, you are spot on, the problem here appears to have vanished. For a variety of reasons cutting off the mains connection during the daytime makes my system work so much better. And if needed it is so easy to allow mains in using the VRM dashboard or a Widget on the phone. You've brought a beam of light to a dark winters day!

Many thanks,

David

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