Ess taking energy from Grid opposed to battery

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Glen McDonald asked Dec 9, '18

Ess taking energy from Grid opposed to battery

Hi, we have a three phase ESS system with quattro 5000, BYD 27.2 kw/h

energy meter and external anti-islanding. Fronius Symo is connected on the Output of the Quattro's - the wifi is not stable and therefore were missing data and incorrect percentage of usage but thats seperate issue.

There is a water pump load connected to the AC Input (100m of copper conductors), but the main switch is off.

The issue is : ESS takes energy from the grid particuallary during the night and early morning, while the battery has energy - usually between 65 - 90% The ESS SOC limit is set to 20%.

Enabling the grid meter does not change the issue. disconnecting the grid meter no change.

The grid energy is 0.1 kw/h and perhaps 0.3 kw/h over 24 hours... But we would like to be zero from Grid.

Thank you

ESS

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Guy Stewart (Victron Community Manager) answered · Jan 28, 2019 at 01:12 AM

Hi Glen,

Thanks for making such an informative question.

To address the issue:

The first thing I would suggest is to please update VEConfigure software and ESS Assistants, and Quattros firmware to the latest versions. Remember to save your settings and reload them as the firmware update will return it to default.

Then see if the problem persists. There have been some improvements made to power output in ESS systems.

If you are using the configuration settings for dynamic current limit as specified in the current BYD Victron manual of a flat 47V is very unlikely that is the cause.

From a business perspective:

I sympathise that the customer wants to see zero, but importing 1 kWh per day of electricity, when they are also exporting 80 kWh per day might not be worth the time and cost of troubleshooting it. The ESS system by design does allow for some flow to and from the grid (both ways). While the grid is connected, the Quattros are not carrying the load. They are pushing and pulling in response to the information from the meters and the controls, co-ordinating batteries, inverters, solar and charge controllers from load and generation data.

While the firmware update may fix it, it is no guarantee and it will require further hours, and cost in excess of the purchased grid power for these spikes.

Finally:

Utility Metering is often done on longer sample rate (eg 30 minute average). Your customer may find that after 3 months when they get their bill, there is actually no cost at all for this relatively small import as it was not counted by the utility meter and is totally resolved by an equal effect in the opposite direction within the metering period.

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Schalk van der Merwe commented · Jan 10, 2022 at 12:59 PM

Thx Guy, i can confirm on older firmware, update after 481 SIGNIFICANTLY made it more sensitive and it feeds back less.

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Answer 1 · 2018-12-09T21:57:45Z

Rob Duthie answered · Dec 09, 2018 at 09:57 PM

Have you set the Grid set point to zero in the ESS setting on the CCGX unit? because the standard setting is 50 watts, which it takes power from the grid, I set mine to zero and it takes nothing from the grid etc.

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Answer 2 · 2018-12-19T21:41:12Z

Glen McDonald answered · Dec 19, 2018 at 09:41 PM

Yes, have tried setting the Grid Setpoint at + 100w , 0 w and -100w

there is no change in energy being taken from grid instead of battery.

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Rob Duthie commented · Dec 30, 2018 at 06:59 AM

Also are you using a grid meter installed separately?

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Answer 3 · 2018-12-20T08:39:27Z

mihair answered · Dec 20, 2018 at 08:39 AM

Hi,

The Victron ESS system is a slow negative feedback system. That means it will always lose energy or consume energy to/from the grid when transition states occur. All one can do is to set the ESS, by modifying the grid setpoint, in sense of making the system always feeding the grid from battery or buying energy from the grid. Negative grid setpoint values exports energy from battery and positive values always import energy.

Regards,

Mihai

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Answer 4 · 2019-01-28T00:37:49Z

Glen McDonald answered · Jan 28, 2019 at 12:37 AM

Hi Rob, Yes I have tried the grid set point. At various values, +100 w to - 400w.

The issue persists and the client is very frustrated. I have an energy meter installed.

Most of the time the value consumed from the grid is .1kw/h over 24 hours that starts to add up.

the issue seems is at the highest value during the early evening, 6pm. Yesterday .4kw/h was

taken from the grid, when the batteries would have been between 99 and 95 %.

These are BYD LifePo4 batteries, could the dynamic current have anything to do with the issue?

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Answer 5 · 2019-01-29T06:23:35Z

Rob Duthie answered · Jan 29, 2019 at 06:23 AM

Hi

When you set the set point it will take a few 10 of seconds to respond to the change it is not instant.

I am using a Mulitplus 2 unit which is only single phase. The dynamic current should have no effect.

Need to see a layout drawing to how every thing is connected.

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Answer 6 · 2021-10-23T13:03:05Z

ganderpe answered · Oct 23, 2021 at 01:03 PM

Sometimes my Quattro is flipping out also with the latest Firmware, when it discharges the Battery into the Grid. This happens not often, but still I'd want to have it fixed please.

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If this happens I'm disconnecting the Grid for 10 Seconds then to on again afterwards the quattro works fine again.

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Answer 7 · 2022-01-10T11:08:35Z

Hi Glen

I think it is more an expectation management problem than a problem that can be fixed.

Unfortunately, the installer (not sure if you are a DIYer/friend or full time installer) should have said this prior to the install to the customer. Someone above use a word/phrase that I was not aware of ("slow negative feedback system"), but I normally just use the example of a old-school scale: if i put a weight on the one side, and it is off-center, and the same weight on the other side to balance it, it takes a few up and down movements (like a seesaw) before it balances out. But the problem is how power is used: in these few seconds another load is turned on and then something is turned off, thus it is always playing catch up.

Looking at your consumption graph, it does not look like you need grid. I have customers who it in the same boat. Two Options: 1.Disconnect completely. This will be a problem if you overload and on extreme low solar conditions, as it is unable to get power from grid when you need it. 2.Put in a contactor that disconnect AC input. You can use the relays on MP to control this contactor and re-connect on conditions like overload, low battery etc. Problem is this will prob not work on overload, as it will take up to 45sec to reconnect in NRS097 is selected, less if you select 'other'.

The reality is we re talking about 0.3kWh per day, similar cost of a chappie(bubblegum). Even over a month, it is less than a 500ml coke. Over a year it is prob half the amount as what he would have spent per month on electricity, all in all a excellent system.

The most important: Other systems are worse, they just don't report on this!! Please keep this in mind, as he might be upset that such an expensive system was installed with this result. With other systems you would not have known as this is hidden and not shown on reports and he would have found out once he had to pay the bill.

My last 3ph system was worse (the kWh feedback that occurred). We overcame it but getting permission to feedback, and they allowed a 1:1 price.

I would gladly have a conversation with you if you want if this is a customer and i can help with what works for me, www.baysolar.co.za.

I really hope all the responses helped.

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