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spithost avatar image
spithost asked

ESS System not feeding in grid :-(

I got a 5k MultiPlus II running with a set of 10kWh BYD LiFePo4 batteries (with their own BYD BMS) en two DC-connected MPPT's with a total PV-capacity of around 2400Wp and a Cerbo "running things"..
The Cerbo is updated to the latest firmware (automagically through the internet). The MultiPlus II is on firmware 2623470 and runs the ESS-assistant more or less with the default values of the German gridcode with internal NS protection.
The only thing I didn't let the assistant change, is the type of battery (because of the BYD-specific settings for Absorption and Float).
This time of year I have quite a surplus of PV-energy so I started experimenting with ESS (Optimized with BatteryLife).
For some reason the system is NOT feeding the surplus of PV back to the grid :-(
Only if I set the grid setpoint to a negative value, the system starts to feed back the PV to the grid at the height I set the negative grid setpoint to....
Otherwise, the BMS (I think) switches off the MPPT's so they don't deliver any PV anymore :-(
For some reason it does that when the BMS says (at VRM and in Remote Console) that the batteries are at 99% instead of 100%. I have no idea why it does that but this doesn't bother me too much ;-).
I set the minimum SOC (unless grid fails) at 95% otherwise apparently the system thinks it should feed the loads from the grid, even when there's still enough PV to do that and even enough to charge the batteries.
So not the actual surplus of PV energy is fed into the grid, but the value set with the negative grid setpoint...
So when there's a cloud before the sun and the batteries are still above the minimum SOC (unless grid fails) then the system feeds the grid from the batteries if the PV drops below the value set in the negative grid setpoint....
I probably have some setting "wrong" to get this result, but I can't seem to think of what could be wrong....
If someone has suggestions..... they are more then welcome.

ESSgridsolar
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netrange avatar image netrange commented ·

Setting in the ESS menu ...

Feeding back into the grid from DC PV allowed ? YES or NO ?

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seb71 avatar image seb71 commented ·
Post screenshots with all settings from ESS (including sub-menus).
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marekp avatar image marekp commented ·
@Spithost

Set "ESS>Mode>Keep the battery charged" and see if PV-DC will feed the grid.

PV-DC will not feed the grid unless battery is charged.

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offgridvoltage avatar image offgridvoltage marekp commented ·

Define 'Charged' in this config ? Above minimum SoC ? or BMS charged threshold voltage ? MPPT Float ? I'm interested as needing a solution to same.

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spithost avatar image spithost commented ·
Actually ESS now is working "partly". But as the cause is probably different, I will open a new "case".
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offgridvoltage avatar image offgridvoltage spithost commented ·
@Spithost Did you resove this ?
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15 Answers
marekp avatar image
marekp answered ·

@Spithost

screen-shot-2022-06-26-at-34653-pm.pngIs "DC-coupled PV - feed in excess" set to ON?


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lifeingalicia avatar image
lifeingalicia answered ·

Hi

1656251036477.png

did you activate this ?

1656251256359.png

From my experience Grid set point and SOC play together.

My system multi 3 only loads excess into batteries except if I go below SOC.

I have also limited charge and inverter power but that is because I can....

Hope it helps




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lifeingalicia avatar image
lifeingalicia answered ·

You probably need DC feed in - it has higer losses but sun is free.....

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lifeingalicia avatar image
lifeingalicia answered ·

Dont forget to check Battery mode - this determins priorities

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spithost avatar image spithost commented ·
what do you mean with Battery mode?
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spithost avatar image
spithost answered ·
Thanks for the suggestions, but I allready had this set ;-)

I set it to 2000W (maximum feed-in)
I don't have AC-coupled PV, so I left this off.


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marekp avatar image marekp commented ·
@Spithost

Do you have DVCC enabled and configured?

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spithost avatar image spithost marekp commented ·
That is sort of "set" automagically. I didn't change that.
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marekp avatar image marekp spithost commented ·
@Spithost

Can you show here your DVCC settings?

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spithost avatar image spithost marekp commented ·

here it is ;-)1656332434535.png

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netrange avatar image
netrange answered ·

Feed back to the Grid ... when Gridsetpoint = 0 and DC Feed Back ON ... only if Battery is full !!!

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lifeingalicia avatar image
lifeingalicia answered ·

did you solve it ?

check this

1656319031192.png

And within the ess assistant is battery mode

https://www.victronenergy.com/upload/documents/Energy_Storage_System/ESS_design_and_installation_manual-en.pdf

4.3.1 and 6.2


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spithost avatar image spithost commented ·

The settings from paragraph 4.3.1 and 6.2 are set to Optimized (with BatteryLife).
For some reason, the system "swings" between the SOC-point of 95% (discharging from around 99% from the batteries with -1500W set in the (negative) grid setpoint) and then charging the batteries again with PV to a point and using the grid to power the loads :-(.
I have no idea why it uses the grid to power the loads, because there's more then enough PV to cover the loads AND charge the batteries....
If I'd know a way to let the system NOT use the grid for the loads, during the charging of the batteries with PV, it would be working the way I'd like and would expect of ESS...

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wkirby avatar image
wkirby answered ·

Do you have the "Use Aux1 as disable FeedIn signal" box set?
You need to un set this box if Aux1 is being used for something else. If Aux1 is closed then FeedIn will be disabled, unless you clear the box.

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marekp avatar image marekp commented ·

@WKirby

But he sais:

Only if I set the grid setpoint to a negative value, the system starts to feed back the PV to the grid at the height I set the negative grid setpoint to....

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wkirby avatar image wkirby ♦♦ marekp commented ·
Hej Marek.

Yes, I did notice that, but just want to make reduce all of the possibilities.

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marekp avatar image marekp wkirby ♦♦ commented ·
@WKirby

I just wanted to make sure that I understand this as I know that do not know everything. :)

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spithost avatar image spithost commented ·
I don't use Aux1 for anything, so I thought this wouldn't be of any consequence? I guess Aux1 will be open, when it's not used?
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wkirby avatar image wkirby ♦♦ spithost commented ·
OK, then this is not relevant for you. Just was to close all the possibilities.
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sfstar avatar image sfstar commented ·
Thank you for this info.

It was the cause of my issues (with the no feedback situation) due to having enabled silence fan assistant (defaults to aux1).

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lifeingalicia avatar image
lifeingalicia answered ·

Just thought - do you use external CT? If so try turning it....

If not - sure phase is on phase and neutral is on neutral.....??


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spithost avatar image spithost commented ·
What's CT? I have the wires connected as they should be. I once had them different and the whole system went nuts :-D


So, since then, I'm VERY carefully that phase is on phase and neutral is on neutral ;-)
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Joe avatar image
Joe answered ·

Did you find any solution? Just suffering the same,
Was opening a new thread but then found this one exactly describing problem.

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Stan avatar image Stan commented ·
What kind of system do you have?

I have MP2 + on-grid inverter + 250/85 + ET340 + cerbo and it worked on the first shot.

In my system I just updated all FW, set ESS assistant and allow DC grid feed with max value and that is it.

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pvmaker avatar image pvmaker commented ·

I have the same problem, my MPPT450/100 is set to 0W power for unknown reason, while another MPPT150/100 is feeding in excess power as expected. This does not make sense to me. Earlier the same day both mppt's where feeding in excess, maybe it is related to the battery soc.

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pvmaker avatar image pvmaker pvmaker commented ·
I was able to fix my problem by resetting both involved MPPT chargers in the system and by NOT setting an aborption or float voltage. I guess this conflicted with the required remote control of the voltages via the cerbo. Excess is now feed into the grid as expected.
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offgridvoltage avatar image offgridvoltage pvmaker commented ·
@PvMaker Can you please elaborate more on your solution ?.... This may be a fix for a very similar dilemma.... What was your exact process and order of resetting the MPPT's and and removing the charge/float values etc ? Thanks ;)
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pvmaker avatar image pvmaker offgridvoltage commented ·

Sorry I can't. This only happens once at the very initial setup on a self-planned and self-installed three phase system with a DIY battery. Setup was quite overwhelming because everything was new to me. All I remember (as already mentioned) is that factory resetting the MPPT's and starting over helped solving the probem for me.

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gazza avatar image
gazza answered ·

Optimised (with Battery Life) has it's usefulness, with lead acid batteries for example. However, the OP is using BYD(Lithium).
I would personally use Optimised (Without Battery Life) since this simplifies the control of minimum SOC, less algorithmic interference.

As an additional settings check.... In Settings>System setup what is "Battery monitor" set to? Try forcing it to the BYD CAN bus? instead of Automatic.

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biggun-benny avatar image
biggun-benny answered ·

Hey @Spithost,

Dont know if got this fixed, but I'll just post what fixed it for me. Maybe it'll help others :-)

So, I also have an ESS system that simply just regulated the pv production to accommodate my loads. In seemed to insist on not feeding back to grid. It was proveable by turning on my oven (increase the house load) then the pv production raised by the same amount.

I have all the settings correct and I observed the same thing with the grid setpoint. Setting it to a negative value would make it feed to grid. So grid feeding was definitely possible.

Looking through the firmware changes notes for my MPPT RS 450/200, I saw no changes that would change anything related to grid feeding. However, updating to fw v3.11 did the trick. My system is now happily feeding surplus pv back to the grid :-)

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larsea-dk avatar image
larsea-dk answered ·

Also very interested in knowing what wrong. When my battery is not full, the system will not feedin excess. I have set my max charge current to 60A, which works when feedin excess is inactive, but once activated, the system charge current is not respected. Serious issue, that the Victron charge with a way higher limit than set!!

I actually expected more of Victron, but maybe they are just not ready for on-grid systems yet which can feedin to grid.

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spithost avatar image
spithost answered ·

Ow.... I didn't realize this issue seemed still open. MY problem was fixed last year actually... With me it was just a stupid mistake. Apparently one of my MPPT's was switched by wire from the BMU of the batteries. When they were full, the BMU switched of one of the MPPT's with the "full stop" wire ;-) and thus switching of that MPPT. Then the remaining one was covering the loads but not having enough to feed the grid, the system didn't :-(
When the wire was removed and the switching of the MPPT's was taken over by the Cerbo, everything worked like a charm. After charging the batteries the excess power is now fed to the grid as ESS was designed to do. So.... if one of you has comparable "problems", please check first, if one (or more) of the MPPT's is hardwired to the "stop charging"-wire of the BMU and (if the MPPT's can be managed by ESS through the Cerbo or alike) remove that wiring and test...

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offgridvoltage avatar image offgridvoltage commented ·

@Spithost Thank-you ;) Can you please explain your solution in more detail ? What is the 'wire' you're referring to ? My LiFePo4 units are connected to the Cerbo via Can Bus cable only.... is there a separate wire you're referring to ? Or part of the Can Bus comms ?

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spithost avatar image spithost offgridvoltage commented ·

It's a separate "wire/cable" (just two leads) between batteries and MPPT. It switches from closed to open or open to close (I'm not sure anymore), when the battery is full. I think every MPPT has such a provision for systems without a Cerbo GX, to be switched of by the batteries directly, when tey are full.
In this way, the battery forces the MPPT to stop producing power, which then can't be fed into the grid.
When I removed this wire, the Cerbo GX took care of the surplus power and fed it into the grid.

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larsea-dk avatar image
larsea-dk answered ·

So it will feed in after your battery is finished charging? Or will it feed into grid after the max charge current for your battery was reached, which I expected when buying the system.

But yes, mine is another issue since I have to much PV power and MPPTs power compared to what my battery can handle. So I would feed in excess to protect my battery from too high chsrge currrent (system respecting my max charge current even at low SOC).

18a9ddc6-6329-40d3-8b53-8ccd722ef587.jpeg


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