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kalito avatar image
kalito asked

Multiplus II ESS grid changeover Issue, resetting appliances

I have a Multi II with a 7.4kWh lithium and 4.3kWp PV and Smart Solar 250/100 coordinated via CerboGX on ESS with self consumption and battery life optimisation


I’ve noticed that when there is grid interruption there is an output break of sorts lasting millisecs. The ledTV, AV system, satellite TV decoder (reboots) and fridge all see the break. These devices have surge protectors I must add (could they be reading the millisecs changeover as a surge?).


When grid is restored the same thing happens. I didn’t have this with a Voltronics inverter. Sometimes even with stable grid sometimes it happens. With grid around this is preceeded by a humming sound from the multi. I cannot speak to the quality of the grid. We are coming from 12hr load-shading in last year or two so supply is meant to be stabilising. Quality issues on frequency affecting Multi?

To stop this annoying ke I switch off AC supply to the multi. But I had needto switch it back on and noticed this issue when there was a 5hr grid interruption. Anyonecare to explain this?


i can run offgrid but do need grid to support load when batt goes below 20% as set in ESS. if off I do get wuite low at times. System can be viewed here:

https://vrm.victronenergy.com/installation/87104/share/80d299b4

ESS
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Kalito,

I am running my house from the MultiPlus-II with ESS.

There is a perceivable flick of some LED lights when the grid drops and resumes, but my computers, internet and other appliances are not interrupted. I am not using any surge protectors, as I found they did cause some issues during change over.

One thing you might wish to look at adjusting is the grid disconnection voltage setting. If the grid voltage sags before the grid is disconnected, the voltage might drop to 190V, then 0V and then snap back to 230V from the Multi and this might be the cause of the issue.

https://www.victronenergy.com/media/pg/VEConfigure_Manual/en/grid-settings.html

In my grid outages are sudden and do not suffer from and voltage sag, but I know in other grids this can be an issue.

So try adjusting that setting, raise it to 220V or something quite high to the normal operating voltage of the Multi and then see if that helps.

I would also remove the surge protectors, if nothing else at least temporarily to test your hypothesis to see if they have any impact.

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kalito avatar image kalito commented ·

Hi @Guy Stewart (Victron Community Manager) thanks a lot I think you have just explained what is happening. The inverter side loads have much better supply than grid and I actually do not need the surge protectors. They certainly do see the changeover and interpret it as a surge. Will implement your suggestion and I will also remove the surge protectors and monitor.

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kalito avatar image kalito commented ·

I interestingly observed the same issue even with the surge protectors removed. This however also led me to notice that we been having very poor grid voltage.

Reading into your comment say Grid is set to 190-260V and reconnect say 197 on low end, did you mean to increase the low or higher voltage range?

If the voltage drops between the set range the Multi shouldnt fret. Is that a correct view? So would setting the lower voltage low say 180V fix the issue you think thereby giving the Multi a wider voltage tolerance?

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seb71 avatar image seb71 kalito commented ·
Reading into your comment say Grid is set to 190-260V and reconnect say 197 on low end, did you mean to increase the low or higher voltage range?

Increase the low voltage limit.

But I would also decrease the high limit to 253V or less if it's now set at 260V (setting for 230V nominal grid voltage countries).

If the voltage drops between the set range the Multi shouldnt fret. Is that a correct view? So would setting the lower voltage low say 180V fix the issue you think thereby giving the Multi a wider voltage tolerance?

You said that the grid is interrupted completely (possibly after first dropping to a lower voltage).

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Paul B avatar image
Paul B answered ·

Also make sure the the UPS option is ON if its off the the transfer speed is slower and you can see a flicker.

As Guy says controlling the disconnect and reconnects can also help

another is make sure week AC it turned off under charger (this may also have a effect)


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kalito avatar image kalito commented ·

Thanks @Paul B I've both weak AC on and UPS turned off. I will make the changes as suggested. However, raising the disconnect to 195V and reconnect to 200V just shows how bad grid is as it does disconnect several times when the grid does its thing. I have sheduled charging set for 6pm and its a pain as the higher settings mean frequent disconnections from grid. It is the cold season where I am and heaters are on in the hood disrupting utility voltage. I have reported the issue seems its a bigger supply issue so guess have to live with it.

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kalito avatar image
kalito answered ·

@Paul B @Guy Stewart (Victron Community Manager) @Seb71 here is the voltage behaviour when grid is disconnected and reconnected to the Multi. The Sony AV system and the fridge see this drop the fibre router and set-top box reboot.


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