Using MultiPlus via MK3-USB as a generator-charger alongside with existing a 3-phase Quattro system

DIY
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1

I would like to verify the proper architecture for the existing setup (3× Quattro 48/10000-3phase system in EU, 4× SmartSolar MPPT 250/100, 30× Pylontech US3000C via Pylontech LV HUB, Cerbo GX)

My interest is to connect 1 phase 230V Backup Generator as Battery Charger - but connected to existing system as follows:

Single-phase 10kW Diesel Generator connected to a dedicated MultiPlus-II (configured “Charger Only”) - connected to a USB port on the Cerbo GX using an MK3-USB interface as secondary VE.Bus instance. Its DC output connects directly to the existing 48V DC busbar. All charge parameters for Pylontech batteries will be pre-configured in the MultiPlus via VEConfigure.

Will CERBO recognise MULTIPLUS as charger? DVCC control CCL and CVL to this secondary MultiPlus-II alongside with 4 MPPTs and 3 Quattros?

Is this setup fully supported in Venus OS as a clean solution for charging a shared DC busbar from a 1-phase generator in a 3-phase Quattro system?

Thank you

4

Use the genset on the Quattro assigned to L1. Beforehand, set “switch as a group” to off.

5

Dear Karl,

Thank you for reply. Please after seting it as you advise, in case GRID fails and my systems starts generator and switch to acin-2 (only on quattro1)

Will system remain as 3-phase system in case AC-OUT?

Thank you

6

My configuration is on snapshot. You mean to switch L2&3 floating ?

Thank you

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7

What does the complete installation look like in terms of the wiring (connect the network to Acout 2 and the generator to Acout 1)? Please take photos of the system and its wiring!

Do you have an electrician to help?

8

Floating means the phases can swap around, don’t do this if you have three phase devices like pumps.

This is the setting Karl is referring to

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It is also unrelated to your set up. Don’t do any of that.

From what i understand you have an inverter separate to your main system.
So your three phase is always inverting. Nice.

So yes, but it would not appear in the main screen but definitely under devices.
But still program it correctly

9

Is this running as an ESS?
If so you cannot change switch as a group.
You can control an independent multi via dvcc as a charge source.

10

Hi Johny,

perhaps this helps a little.

Generator and ESS is well discussed here

Other solution is to use a PSU, search for Eltek Flatpack in this forum

11

Thank you… This is exactly what I’m planning to do…

  1. I don’t want to touch the running 3-phase QUATTRO system with ESS (removing “switch as a group” would remove assistants) - I understand that I have the option to buy a 3-phase generator with a perfect sine wave to connect to AC-IN 2.

  2. I want an independent charger, but under the supervision of the current system (GX + Quattros).

Please, could you confirm if this option is acceptable: 1-phase generator → MultiPlus → existing DC bus (3 quatros, 4x MPPT, 30x pylontech), connected to Cerbo with a MK3-USB cable (of course proper configured only charger for pylontech battery?

  1. There is also another option, I think… (1-phase generator → AC-DC inverter (4x Eltek Flatpack2 380/3000 HE) → Victron SmartSolar MPPT RS 450/200). This 3rd option is more complicated (and more expensive), but I think it’s more native to the Victron system.

I will prefer option 2… if I get approval.

12

Dear Dirk,
youre great…thank you…your link exactly explains and confirms my plan…one picture says all…

Screenshot 2026-09-22 at 21.43.56
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13

Yes, the additional information that followed confirmed the second solution, as Dirk pointed out in the link.

Good luck with your setup!