ESS manual - DC-coupled PV - feed in excess - incorrect information?

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marekp asked May 21, '23

ESS manual - DC-coupled PV - feed in excess - incorrect information?

I found this statement in the ESS Manual.

https://www.victronenergy.com.au/media/pg/Energy_Storage_System/en/configuration.html

4.3.4. Feed-in excess solar charger power
Set to 'On' to make the solar charger always operate at its maximum power point. The first priority is powering the loads, and the second priority is to charge the battery. If more power is available when those two priorities are met, then that power will be fed to the utility grid.
Please note that when enabling this option, the DVCC charge current limit configured under Settings → Limit charge current won't be active. The solar charger will operate at full power for maximum feed-in into the grid. It's advisable to configure a safe limit on the solar chargers when used with a small battery bank.

In my system when, in ESS, I turn "DC-coupled PV - feed in excess" ON, I still have the DVCC option "Limit charge current" active.

Is ESS manual in error?

ccl ecc

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Answer 1 · 2023-05-21T11:39:46Z

nickdb answered · May 21, 2023 at 11:39 AM

The option and setting remains, it will just be ignored.

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marekp commented · May 21, 2023 at 11:55 AM

@nickdb

The information in ESS manual suggests that CCL option is not active at all.

In reality it is active but only for inverter/charger.

When you have DC excess feeding "ON" and you set the CCL to ZERO, the inverter/charger will not charge the battery, but MPPT will.

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nickdb ♦♦ marekp commented · May 21, 2023 at 11:59 AM

Most ESS systems rely on solar to charge, so the docs are quite accurate in that respect and since the setting is intended to be global (since DVCC coordinates charging across all devices), saying it isn't active seems like a reasonable statement to make.

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marekp nickdb ♦♦ commented · May 21, 2023 at 12:09 PM

@nickdb

But MPPT charger is not the only source of PV charging.

ON-grid PV inverter (connected on the AC side) can also charge the battery. It is doing it through Inverter/charger.

Only DC charging by MPPT charger cannot be controlled by CCL in DVCC after DC excess feed in is turned ON.

Charging by Inverter/charger and ON-grid PV inverter can be controlled in DVCC.

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Answer 2 · 2023-05-21T11:45:55Z

pedaaa answered · May 21, 2023 at 11:45 AM

you cannot remove this parameter, as it is still active for the multis.

Just Solarcharger ignore this limit.

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marekp commented · May 21, 2023 at 12:01 PM

@Pedaaa

The way I understand "not active" is that I cannot select it because is "greyed out".

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pedaaa marekp commented · May 21, 2023 at 12:09 PM

but that is just wording and interpretation.

But i agree somehow. Victron should better explain this detail in the manuals.

As reading through the forums, many many many users don´t understand how this works.

But it is simple indeed:

if DC-feed-in is ON:

MPPT Solarcharger won´t listen to CCL

it will charge with full power, only limited by CVL+0,4V.

Multiplus is limited by CCL and CVL

(so also AC-coupled PV-inverters are limited by this as well)

if DC-feed-in is OFF:

MPPT Solarcharger as well as Multis are limited by CCL and CVL

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marekp pedaaa commented · May 21, 2023 at 12:31 PM

@Pedaaa When one writes the manual the "wording" is everything. There should nothing be left to "interpretation".

It is simple indeed and it should be explained in such a way that there is no room for interpretation.

Exactly like You did it.

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nickdb ♦♦ marekp commented · May 21, 2023 at 12:06 PM

I don't recall victron ever using "active" with that definition, so that would appear to be a misinterpretation on your part.

Even "active SOC" refers to a limit that is currently in use.

Also remember, the moment you disable feed-in, this limit would become active again.

I think you're confusing it with "available" or "configurable".

All just semantics.

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marekp nickdb ♦♦ commented · May 21, 2023 at 12:35 PM

@nickdb If there is a room for misinerpretation that means manual is not well written.

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marekp nickdb ♦♦ commented · May 21, 2023 at 12:54 PM

@nickdb

@Pedaaa

Also it would be nice if this manual showed the current view of the ESS assistant.

It shows it like this:

When in reality it is now this:

and

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ess.jpg (51.3 KiB)

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Answer 3 · 2023-05-22T08:04:13Z

markess answered · May 22, 2023 at 08:04 AM

Yes the Limit Charge Current setting for me just affects the power into the battery coming from the solar inverter through the Victron. The MPPT direct charging the battery is not affected.

So it seems you can't easily fully prioritise export with ESS if you have an MPPT (sometimes required in UK as we currently have some competitive export tarrifs), although I guess this is not really an ESS use case. Solved with Node-RED though.

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Answer 4 · 2023-05-22T09:13:05Z

baxter answered · May 22, 2023 at 09:13 AM

Maybe the wording in the DVCC manual is not misleading for you

"6) DVCC charge current limits are not applied to DC MPPTs when ESS is enabled with Allow DC MPPT to export. This is to get maximum output from the solar panels for export."

https://www.victronenergy.com/media/pg/CCGX/en/dvcc---distributed-voltage-and-current-control.html

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markess commented · May 22, 2023 at 09:26 AM

Yes it is a bit odd wording. If you want max export then you don't want PV going to battery. Shame the current limit is not system wide. I use Node-RED to set battery current=0 if I want to idle the battery.

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