question

Glen McDonald avatar image
Glen McDonald asked

ESS system uses grid energy when before the battery.

Hi, I have asked this question previously - but after 12 months the issue is continuing.

The system is 3 x Quattro 48/5000 setup in 3 phase. After the batteries have been charged by PV for the day, often the BYD LifePo4 batteries are between 75 - 100% - the system is operating in ESS mode as expected, the house output loads are low, perhaps 1200w or 1500w is drawn on Phase 2.


Please see 2 images below:


We obviously expect the load energy to be drawn from the battery, instead it is taken from the grid supply? this could occur for 5 or 10 minutes.

The Carlo Guzzi grid meter is balancing the phases, ie -719w on L1 and +785 on L3

Im well familiar with the operation of ESS systems and settings, but this one has me confused.

I have tried the "switching off the grid meter" I have tried lowering the Grid set point to 0 and even -20w. But day after day the problem continues.


The image below from VRM Portal shows 0.4kw/h per hour from battery! this should be near zero, as the battery are fully charged.

Is this simply an error in the VRM display calculations, that could be proven by taking readings from the Household grid revenue meter?

This issue is obviously annoying.


Thank you for your consideration with this matter.

Glen McDonald

Elementary Solar


ESS
l2-uses-1200w-from-grid-instead-of-battery.png (293.5 KiB)
screen-shot-2019-11-22-at-103510-am.png (129.0 KiB)
l2-uses-1200w-from-grid-instead-of-battery.png (293.5 KiB)
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2 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @GlenOmata

Did you figure it out yet?

If you want help you also need to post AC-use graphs, could very well be there is a load on phase 2 that is to big to be handled by that inverter, and so the other phase is helping to compensate.

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Janek Plathe avatar image
Janek Plathe answered ·

Hi Glen,

Just found your question and unfortunately I don’t have an answer. I actually posted an similar question here yesterday, maybe you have a look and if it seems familiar to you we liase our efforts.

In my case I see almost the entire day „grid consumption“ in VRM being recorded with 0,1 or more kWh per Hour. Only seldom I am completely on battery... and this even if battery is full and no overload on inverter.
I have sometimes the feeling the gridmeter telling the GX how much to compensate is to slow or wrong, especially if larger or varying loads are existing (I.e washing machine).

It’s especially annoying if you actually feed valuable kWh from the battery into the grid for nothing during winter :-).

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Hi @SeemannJanek

Are you by any chance using an ET340 grid meter?

if so: see Q9 here:

https://www.victronenergy.com/live/energy-meters:start#faq

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Janek Plathe avatar image Janek Plathe Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Hi Daniel,

Yes, I use an ET340.
and after I found another older Thread with the same symptoms it seems to be the issue with the VRM calc algorithm - hoping for a fix in future. Would be a pity to buy an EM24 just to solve this problem.

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ Janek Plathe commented ·

Hi @SeemannJanek

The problem is with the way the ET340 works, the dashboard uses the figures straight out or the grid meter, so we cannot change this unfortunately.

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