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Are my lights supposed to flicker when my Multiplus switches off grid


Basil Katakuzinos
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So when i have load shedding and eskom goes down, i notice a significant dimming in my lighting(To me it appears as if they turn off completely even if only for a split second). My frezer compressor also makes quite a noise during this time. I think i can rule out DC wiring as the problem because the inverter was feeding the loads before the grid went down anyways (No sudden change in DC current).

Is this normal, am i being overly observant and critical?

Inverter is a Victron Multiplus II 5kva with 3xUS3000C 

I will try record a video of the change over happening tomorrow. 

 

EDIT

My lights also flicker slightly every +-30 mins... not enough to be irritating or to effect anything, but it is enough to notice

Also my lights are all incandecent GU5.3 Low voltage lights (I will change them to GU10 eventually, just need to finish with exams first!)

Edited by Basil Katakuzinos
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18 minutes ago, 87 Dream said:

Basil, what voltage is the Eskom grid providing? Also what output voltage is the Multiplus pushing out? To test the Grid voltage you can use a Multimeter & push your terminals into a plug point. 

I have had this phenomenon on a couple of sites before getting to the source of the issue. You need to align the Grid & inverter output voltage. 

I cannot speak for the settings on the Victron Multiplus, but on Voltronics machines there is an option to choose between 220, 230 & 240 volts. The Eskom grid will be supplying a certain one of these maybe even 245V odd volts it's not perfect. But if you align the inverter output to this then the dimming effect is significantly less. 

In the case of the Voltronics, this issue came across because when grid or utility is the primary source the inverter is merely a conductor. However, when the grid is lost through loadshedding, the house voltage changes to the higher or lower voltage. Which the case may be. This change over is presented when your lights either dim or brighten. The instantaneous almost blackout is more pronounced if this voltage is different. If you align these voltages this effect is barely noticeable or to a much less pronounced degree. 

This happens because for your lights or appliances to keep the power the same wattage. If the Voltage is dropped or lifted the amps need to change to keep the power output constant.  Power(Watts) = Voltage X Amps. 

 

87

Have them matched to within 6 Volts, As close as i can get as eskom voltage changes depending on load on transformers, i can also see sudden voltage changes occur (10V) as the transformer/voltageregulator taps move up and down on their windings which i think is cool.

Edited by Basil Katakuzinos
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17 minutes ago, 87 Dream said:

Wow, then you are already as close as you can get. It solved my issues. I can't talk for the Victrons of this world. I'm an Axpert whisperer, Blue power is like unicorns to me 😂😂😂☺️

87

My best guess is that it is those pesky Low Voltage light transformers, once i change a few zones to GU10 ill be able to confirm.

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  • 2 weeks later...

So... removed basically all of the loads except a computers,  a tv and 8 lights... this change over seems rather significant to me, as if all the lights are going off and then coming back on. I also notice obvious brown outs (very small during eskom). I am hoping someone with a victron (perhaps @Sarel?) could tell me if this is normal. I have attached the video of the power going out recorded on a selfie camera at 30fps. Excuse the messy view, i just left the camera proped on my desk waiting for load shedding.

Recording was at 30fps and the flash appears to be 2 or 3 frames so thats 0.1 seconds, 100Miliseconds!!!

Edited by Basil Katakuzinos
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Nope, cannot imagine that being normal. That being said, there are so many things it could be…. Can you start by sharing the details of the system please.

  • What exact model Victron
  • do you have a GX
  • do you have any assistants loaded
  • if so what are they
  • Are you on the vrm portal
  • if so can you add me please

Many more questions but lets start with this.

on appearances only, it seems that the inverter is either switching from one source to another or there could be a large load spike of short duration. Any chance that something else may be powered by the inverter that are plugged in somewhere? What are tha battery cable size and length between the bank and inverter?

 

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46 minutes ago, Sarel said:

Nope, cannot imagine that being normal. That being said, there are so many things it could be…. Can you start by sharing the details of the system please.

  • What exact model Victron
  • do you have a GX
  • do you have any assistants loaded
  • if so what are they
  • Are you on the vrm portal
  • if so can you add me please

Many more questions but lets start with this.

on appearances only, it seems that the inverter is either switching from one source to another or there could be a large load spike of short duration. Any chance that something else may be powered by the inverter that are plugged in somewhere? What are tha battery cable size and length between the bank and inverter?

 

 

Thank you for your response!

I have tried to answer your questions below

Victron Multiplus II 5kva + 3 X Pylon US3000C (They are connected via 70mm2 cable that is about one meter long) 

Inverter is connected to BMS via CAN BUS and i can see the battery in the settings page.

running ESS Assistant( I will screenshot the settings pages below.) I also have DVCC enabled.

I have a Venus GX

Load was a consistant +-800 watts when change over happened, i suspect the fridge was on also. 

image.png.6fbddadf08619bc13535259b853985b5.png

Towards the left of the graph below we can see the instant the power from eskom tripped, I can see a massive spike in current but do not know what to make of it.

image.thumb.png.c34a2b66a7cfde77414924654d1bfd9a.png

Here is a graph of the DC Side from the perspective of the inverter, i am hovering my mouse exactly over the time where the AC IN disconnected

image.png.ff2823e2fb482a22bc3f62c3ebad1f25.png

Edited by Basil Katakuzinos
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AC in Voltage looks ok. Dont know about that spike tho. DC side and AC side shows same spikes as current drawn from the battery about once per hour, refrigerator maybe 🤔 

On my system: Voltage from Utility side 243V and drops to 230V on battery. Now my Utility supplies very little current normally, just a few watts. But the inverter output Voltage rises to whatever the Utility provides and falls to the set voltage with no Utility present.

411F473A-DCD1-4409-93DE-AD503185CFD1.thumb.png.f3ab8676ca869a10d8a45dd572077c9b.png

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Just a thought. Add a load like a kettle while lights are flickering and see what happens? I postulate that the flickering happens under low load conditions.

The control loop in the inverter cannot instantly change and under certain conditions oscillate a little. If you change the load, especially if the load on the inverter is low, it should stabilise if I am correct. Let us know.

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