Periodic maximum discharge after battery upgrade felicity LUX-X48100LCG01/LMG01

DIY
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1

Hello,

I recently finished my Solar System with 3 MP2 (one of them is a GX).

In the beginning I had 1 LUX-X48100LCG01 und 3 LUX-X48100LMG01.
They were interconnected with each other and then connected to the MP2GX via CAN.
The battery was/is detected as a Pylontech Battery.

I configured the ESS in accordance with the pdf from @Angie-Felicity.

Everything was working fine, I use a Shelly Pro3EM as a grid meter via Modbus TCP, grid point set to 0.

After one week of operation I decided to go max on the battery so I orderd 4 more LUX-X48100LMG01. Before connecting everything i made sure they all had roughtly the same SOC and were within 1 Volt of each other (Felicity guide sais 3 Volt but that seams a bit much for me).

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Since i have this setup i get eratic/periodic discharge power bursts of 13 kW. So every MP2 feeds into the grid with max power. The SOC of the battery does not matter.

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I thought maybe that was to balance the packs and cells but we had realy nice sunny weather for the last 4 days and the batteries were all at 100% SOC for 2-3 h per day. Is this enought to properly balance the packs and cells withhin?

I then changed the grid meter to the internal sensor of the MP2 because maybe I was getting wrong readings, but nothing changed, I still got max bursts of battery discharge.
These bursts only last 2-10s. I was unable to identify a pattern.

On the remote console i get lots of High cell voltage warnings, but according to other users this appearently is normal when you have a new system and the cells are getting balanced at high SOC.

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I think the eratic bahavior has something to do with DVCC which is forced to “ON” via the Battery BMS.

I only started getting these discharge spikes after upgrading the battery to 8 packs.
Grid meter before the Upgrade:

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Do you have any idea what is causing this?

Thank you,
Hichi

2

So, what I found out is that the CVL changes also randomly periodicaly:

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This correlates roughtly with the discharge spikes I am getting:

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I have now disconnected the new packs.
Since 16:30 CVL is stable at 57,6 V and I got no new discharge spikes.

So, what I think is happening:
The BMS reports a CVL below current charge voltage.
The Multiplus II panics and tries to get CV below CVL by dumping as much energy as possible into the grid.

So my hypothesis is that one of the BMS of the individual new packs is reporting a wrong CVL.

I will now step by step connect more and more packs to identify the faulty BMS and contact the seller afterwards.

Hichi

3

Hi, this is caused by victron recognising the battery as 15 cells by default, you can try upgrading the inverter, or buy smartshunt

4

Hi Angie,

why would victron “detect” the battery as 15 cells? I configured everything per your companys guidelines. Also the CVL is transmitted via CAN bus from your batteries BMS.

So at least one pack is sending wrong CVL value.

I will check if the Multiplus II is on the latest FW.

I have the system currently running on the original 4 packs I ordered in December 2024. I had not a single “power surge” event since recreating the original configuration before the upgrade from 20 to 40 kwh.

I will identify the faulty battery pack and contact the seller here in germany.

6

Hi, as far as I know, some models of victron’s inverters or MPPTs just default to recognizing the battery cells as 15, it’s a historical problem with them, and I’ve heard that upgrading the inverters or controllers fixes this. We have some customers who have also solved this problem by purchasing smartshunt as an accessory.
If you want to upgrade your batteries at the same time, I’d be happy to help you with that as well.