I am a Victron installer and I would like some advice regarding a system design.
Equipment:
1x Victron Quattro 10kVA
1x Victron Quattro 15kVA
6x MPPT 150/70
Pylontech US5000 battery bank (compatible with Victron)
1x Cerbo GX (with WiFi modem)
Objective:
I would like to:
Connect both Quattro units to the same DC busbar (same battery bank)
Use a single Cerbo GX for monitoring
Use the same battery bank (Pylontech US5000) for both inverters
Each inverter will supply a completely separate AC installation (no interconnection between outputs)
No ESS assistant (off-grid style operation)
Main question:
Is it possible to use two Quattro units of different power ratings (10kVA and 15kVA) on the same battery bank and same Cerbo GX, without paralleling or synchronizing them via VE.Bus?
Additional questions:
Can both inverters communicate correctly with the Pylontech battery (BMS) via the Cerbo GX?
Are there any limitations or risks when sharing the same DC busbar?
Is any specific configuration required to avoid conflicts?
Would you recommend this architecture, or is it better to separate the systems?
Connecting multiple VE.Bus systems to a single Cerbo GX
Only one VE.Bus system can be connected directly to the GX device’s built-in VE.Bus ports. To connect additional systems, consider the following options:
Option 1: Use an MK3-USB interface
This method allows multiple systems to be visible, but with limited functionality:
Only the system connected to the built-in VE.Bus ports contributes data to the Overview pages.
All connected systems appear in the Device List and are included in VRM energy statistics.
DVCC and ESS control applies only to the system connected directly to the built-in VE.Bus ports.
Additional Systems connected via MK3-USB do not support DVCC control and will follow their own internal configuration for charging/discharging.
There is an option (Settings → System Setup → Charge Control) to enable BMS control of a secondary inverter/charger connected to a GX device via an MK3-USB interface. When enabled, the secondary device will follow the CVL and DCL values provided by the CAN-connected BMS.
Generator start/stop logic applies only to the directly connected system.
For ESS systems, only the system on the built-in VE.Bus ports participates in ESS mechanisms. Others are visible in the Device List only.
Option 2: Use VE.Bus to VE.Can Interface (ASS030520105)
The limitation is the battery bank. Can it do the full over load of the combined system without tripping. You ideally want a bank that stays on and powering everything and the inverter(s) trips if there is a fault.
10kva + 15kva =15kVa (actually technically a short peak of 2x that) amp discharge?
We have a battery installation with a capacity of 2100 Ah, which should be able to handle the different current peaks.
Do you know of any projects or people who have already implemented this type of installation?
If you dig around on the forum, there certainly is a range of installations, this included, as well as ones where additional multis are used purely for charging (DVCC now supports this iirc).
Capacity is different to discharge current. Which is why i being it up as the two often get mixed.
The battery bank has to be able to at least discharge 520A nominal continuous and a peak of 500A for a few seconds without tripping. And the cabling from the bank to bus bar at least equalas the discharge gauges coming off the bus bar. And then it all arranged so that it current shares neatly over it.
Yes i have seen and know of projects similar tp this. As Nick mentions there are quite a few on the forum.