I have a Victron Setup with 3 Mulitplus2 48/3000, the Cerbo GX, an MPPT, two Fronius Inverters and 2 DIY 48V LiFePO4 batteries.
While using the system with one Battery of 16kWh everything was fine for several months. Since I recently added an identical second battery in parallel, Victron spikes full power into the grid every 30 minutes when the batteries are full. Shortly after that victron begins to recharge them.
The Batteries are equipped with a JK BMS and communication to the cerbo works fine.
I have DVCC enabled and already installed the latest FW on the MP2 and on the Cerbo, but it didn’t help. (So I switched back the servo to V3.33 because I like the old console better:-)
Any Idea where this could come from?
Screenshot from VRM portal (spikes barely recorded):
I’ve seen the same max power spike when switching from Absorption (55.20 V) to Float (54.00V).
The system exports full power into the grid to drop the battery voltage.
Maybe in your case the JK BMS requests a lower charge voltage (CVL)?
Another possibility, if you have older MultiPlus II inverters, there was a problem with the 3.5mm jack for the external current sensor and ESS would behave erratically. On newer inverters they used push-in connectors instead of the 3.5mm jack and eliminated the source of this problem.
I actually had the RCV (Requested Charge Voltage) set to 55.2V and the RFV (Request Float Voltage) to only 53.6V. Now I increased the RFV to 55.2V as well, let’s see if the spikes are gone from now on.
I checked it today and can confirm that the spikes are gone after fixing the too low Float voltage setting. Your very first hint solved my issue, thx again!
