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tim84 avatar image
tim84 asked

ESS assistant with two-signal BMS support

Hello,

I have a problem with the two-signal BMS support in the ESS assistant.
The two-signal BMS support is described very simple and clear in this document:
https://www.victronenergy.com/upload/documents/Manual-Connecting-other-lithium-battery-systems-to-Multis-and-Quattros-EN.pdf

One signal input is used to allow charging/disable charging and the other input is used to allow discharging/disable discharging.

I selected "Disable charger" on the high-cell/battery full condition. When the BMS activates the input of the Multi, the CCGX shows "ESS #3", which means "BMS disabled charging". But the problem is, that the charger AND the inverter stop working in this case. This doesn't make sense in my opinion, because the battery is full and cannot be discharged, because the inverter is also disabled. So the system locks itself and remains in this state and cannot leave this state.
Then I switched the "Battery full"-input manually and could reproduce this behaviour as long as I wanted: The Multi is in inverter mode and discharging the battery. Then I activate the input and the inverter stops immediately. Then I deactivate the input again and the inverter starts again with discharging the battery.

When I select "Force to float" on the high-cell/battery full condition, the inverter is not affected and not disabled in this case. So this seems to work fine.

The "Battery empty"-input also works fine and only switches off the inverter, whereas the charger is not affected and still works.

I found an entry with the same problem form last year here:
https://community.victronenergy.com/questions/18191/ess-with-2-wire-bms.html
In the first answer from May 27 '19 dunno describes the same problem, which I also observe with the option "Disable charger" on the high-cell/battery full condition, but there is now answer to his question.

Can someone help of the Victron team?

Best regards
Tim

ESSBMS
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4 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Tim84


I'm thinking of this possible issue (aux1 input double assigned):
https://www.victronenergy.com/media/pg/6292-ESS_design_and_installation_manual-html5/en/faq.html

Q9: feed-in may be disabled when a grid code (like the German or Australian grid code) uses the aux1 input to disable feed-in, and aux1-in is used by something else (like an AC-sensor or a BMS), this way feed-in can be disabled. Simply un-check the option in the grid-code settings to prevent this.

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tim84 avatar image
tim84 answered ·

Hello Daniël,

thanks for your answer.
I already read these hints during the installation and also tried it with the Temperature sense input.
But also with the Temperature sense input, I observe the same problem. So your idea is not the solution for the problem.

I already asked my Victron dealer and I also asked a Victron sales manager. But nobody is able to give me a serious explanation for my problem and to help me.
Therefore the community is the last chance for me.

Best regards
Tim

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

do you have a battery connected when trying this? (assuming you're using two switches to simulate the bms input?)

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tim84 avatar image tim84 Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Yes, of course, the battery is connected. Otherwise I could not test to charge and discharge the battery.
Yes, I use two switches/two inputs for controlling charging/discharging as described above.

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Victor Bonilla avatar image
Victor Bonilla answered ·

Hi @Tim84 i have the same problem.

If I choose the option "disable the charger" with Aux1 (battery full charged) the inverter stops inverting.

When the battery reaches 0%, AUX2 empty, the ESS begins to charge the battery, without apparent explanation, with the current programmed in the charger tab, until AUX2 is deactivated and begins to invert again. Creating continuous charge / discharge cycles. I have put the maintenance voltage below 47V, well below the minimum voltage of the battery in disconnection.

1606935788970.png


why doesn't it work as it should? How to program it?

It is simple:

- Full battery, inverter and solar stop charging.

- Battery empty, inverter stops inverting and takes grid consumption.


@cquinones (Victron Energy Staff) tenemos solución a esto?


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Magnus Pernemark avatar image Magnus Pernemark commented ·

@Daniël Boekel (Victron Energy Staff) I can confirm this. Exactly the same thing happens to me. When disable charge is triggered, it also disables discharge.. BUT ONLY WHEN IN BULK. If you reach absorption, it works as expected.

If you disable discharge and allow charge and on a grid connection. Inverters start charging at full power, regardless of ESS grid settings.
1628846212297.png1628846239081.pngAnd the other bug I reported som time ago. If using ESS and your in absorption... when inverter switch to float, they discharge the excess to grid - at full power - regardless of grid setting, causing a massive flow of energy for a brief period.

It would be nice if Victron could focus on the hardware bugs. This bugs would probably be easy to recreate in a lab. These bugs are also a major showstopper for ESS especially in the winter, when battery more easily runs out, and you would like to control the charge your self and not just let the inverter start when ever it feels like it.

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Paul avatar image
Paul answered ·

I tried the ESS assistant in a MP 48 5000/70 with a two-line charge/discharge control and get the message that this can't be combined with ESS (is this for the Lynx system only?).

Using a Batrium BMS with two outputs for too high or too low (cell)voltages, this would be a nice combination however, I chose to go for an ABB 400A tripbreaker with coil that shuts down the battery if something goes wrong.

Since CANbus comms with Batrium aren't perfect at the moment, this will be the only option I fear.


Anyon who knows why the ess/2-line bms assistant is not allowed?


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