question

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seriusrod asked

High grid usage since v500

I've been noticing a high grid usage since version 500 of the MP2 fw.

My system is setup in a ESS zero feed configuration and with a setpoint of 0. The normal grid consumption interval is between 70 and 180w. The house consumption is not that high, normally at 450w, so the grid power usually is a 1/3 of the total consumption.

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Also with this problem above, I also noticed that the system always overcharges the battery. I have 14s/13kWh of lithium configured at a max. voltage of 56.8, but it continuously gets charged to 57.4v. I guess that the only thing that prevents it from overcharging it's the BMS that kicks in at 4.09S for balancing.
Configuring DVCC to 56v has no effects. DVCC seems totally inutilized. Current limiting also doesn't work.

Is there any way of opening an issue for this kind of bugs so we can trace them and know if they are being followed or addressed by Victron technicians?

Is there a way of rolling back the MP2 fw to a well-known version?

My system: MP2-5K / 14s-13kWh-57v Lithium / BMS not integrated / Smartshunt / MPPT 150/80 ve.bus connected / Fronius 5K integrated.

EDIT:

When the Max.Charge voltage is set to 56, the battery gets charged up to 56.7. That seems in line with the numbers I got when I had the voltage set to 56.8.

20230417-voltage-56-but-charges-to-567.jpg

Also I've noticed that when the charge is completed, the grid setpoint offset seems to normalize.
So it seems to me that may be a problem with the ESS charge algorithm mapping. There was plenty sun available during the charge, the system was throttling the Inverter and Charger, but at the same time getting energy from the grid to charge the batteries.

EDIT:

That's insane... no one?

20230419-095042-from-grid-without-necessity.jpg

ESS
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2 Answers
seriusrod avatar image
seriusrod answered ·

I'm starting to think that the culprit is the SmartSolar mppt, when it has grid export enabled even when it is limited by the watt limit below.

Leaving only the inverter feed active or in rainy days, there is no problem in the system.

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seriusrod avatar image
seriusrod answered ·

Those problems still persist after upgrading the Cerbo to v3.0. They appeared after I moved from 2.92 to v3 betas.


Some days ago I experienced a dangerous situation when I was offsite and I started to receive alert messages about the battery being charged at more than 58v while max voltage is set at 56v. The system was still charging at 50A at this voltage.

photo-2023-06-07-10-12-02.jpgAnd the grid setpoint is still crazy. For it to being near zero, I have to have it configured at -80. If not, it goes up to 300w. It is related to sun production as it calms down when production stops. My grid plan costs 38cts€ per kWh.


It's a shame that I've been asking for support from Victron and my posts are all still unanswered. I thought Victron was a reliable choice. A real shame.


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