Second Victron ESS as Backup-System

Q&A and troubleshooting
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1

Hello,

I have a fully functioning ESS system with 3 phases from Victron, everything works great in stand-alone mode.

I still have 3 Victron Multiplus and a BMS lying around. My question is, since I don’t have any more space, I would like to build 2 Victron ESS without solar as a 3 phase system with batteries.

My idea was, if possible, to add the 2nd system and when the batteries in the 1st system are full, to use the excess current to charge the 2nd system. Is it possible to program and install it like this?

Regards

2

A comment from me on another topic
But the function principle is nearly the same:

For you the system A should also be a ESS with Meter.
On top of this vou would need a second Hager SFT440 (or something else) to switch the Input if the two systems to the grid (if system A fails or while maintenance).

3

I’m doing exactly the same in my setup

You may see it in other thread

4

Hello again,

my plan would be for everything to run fully automatically. As soon as the primary ESS has 100% battery, the solar power should be used to charge the secondary ESS. The rest is in the picture. What would the programming or wiring for the AC side look like?

ESSVIC
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5

Just upgrading the batteries on the existing unit makes more sense.

6

Sorry i am not stupid ESS Primary hast 100kWh storrage thats the maximum and i will not throw away 3 good Multiplus Inverter / Charger

7

Did you write that you’re at max anywhere ?

8

I have also no more space, and i have still only 2 Years old Multplus 24/3000/70 + 5 BMS + Gerbo GX. thats the reason i am asking to combine 2 ESS systems, and how wir

photo_2024-12-13_18-26-41
photo_2024-12-13_18-26-41576×1280 121 KB

ing must look like

9

I’m using NodeRed where in primary ESS I’m detecting solar excess, sending mqtt message to secondary ESS, where switching to “keep batteries charged”

Once on primary ESS battery falls to less than 95% SOC - toggling secondary ESS back to “optimized without BatteryLife”

10

Sounds good can you tell me more :slight_smile:

11

Here is a video, where I’m covering slightly part of excess solar usage https://youtu.be/RQNFCH41R9k
I’m sending signal from first GX to second GX where by reacting on it I"m changing to “keep batteries charged”