Hi all
It seems at the moment its impossible. I think the problem is not just a fzsonick problem. it its
a problem with all batteries they have an own bms with internal dc/dc converter.
the situation
Offgrid!
6x Multiplus2 5000 48 / 3 phase, newest software
on AC out Fronius Symo 15 Firmware 35020, MG50, NormalPowerChangeGr Ramps are set.
3 FZsonick Batteries 600 Ah 48V connected to GX with rs485 modbus rtu
Cerbo GX v3.3
Setup Fronius and Multi:
https://www.victronenergy.com/live/ac_coupling:fronius
Datasheet of FZsonick
The BMS of the 48TL200 battery is equipped with an integrated charge regulator, basically a DCDC step-down (Buck) converter. The battery accepts any voltage between 54 and 59V, and regulates the charging current and the charging voltage to the optimal levels. Recharge current is limited by the BMS to 40A therefore there is no need to limit the current at the rectifier level. To charge the battery, a simple DC power supply can be used. In any case the BMS is fully compatible with any typical rectifier used in the telecommunication market.
If the BMS detects that the SOC of the battery is below 100%, the charge phase is automatically started. This is indicated by the blue LED which will turn solid on while the display of the battery alternatively shows all the charging parameters (voltages, current).
Different Settings
Multiplus
Charger
- Absorbtion Voltage 54.20V
- Float Voltage 54.20V
- Charge Current 40A
ESS Assistent
Cut-Off Voltage
- 0.005 C = 40.00 V
- 0.25 C = 40.00 V
- 0.7 C = 39.00 V
- 2 C = 39.00 V
1. Problem
The FZsonick Batteries have an internal BMS and DC/DC Converter.
They have a delay of 15 seconds before to start charging.
When the sun rises and power comes from the modules, the Multi regulates with the frequency control to the point that 0A flows to the batteries. However, the batteries do not switch to charging mode. If I help with a normal 48V power supply on the DC side, the batteries start charging mode and the Multi regulates the frequency down so that the Fronius can supply more power.
After that i can disconnect my normal power supply. and the batteries are chargeing from Multis with Fronius.
Update 2024/04/18: There are different firmware version of the battery avaliable. One of them is optimized for solar applications and have no delay. If everybody have this problem you must change the firmware.
2. Problem
If the load increases for example 2000W. that works if the fronuis deliver 5000W. But if the load of 2000W will be interrupted. The Multi sends 53Hz to the Fronius and the power goes down to 75W. Thats in the most cases. In some cases some Multis are complaining with "Overload" and "Low Battery" => No frequeny Change ! No messsages in the GX. I must power of the Multis to restart them.
3. Solution ?
Perhaps the Problem is the Multi don't know how many current the batteries can use for charging.
A solution perhaps can be: Chargeing only with the half of the maximum charing current for example 20A and if some load will be interruptet than can the rest of the current send to the batteries and the multis can regulate it down to 20A.
Have everyone the same situtation ?
Extended discussion in german:
Thanks
Thomas
