Shunt question, mostly about VRM presentation

Q&A and troubleshooting
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1

Hi all. I’m trying to put together a system and I need some non-victron components in the mix and I’m wanting to use smart shunts to get data into VRM.

here’s the jist of the build:
stack of lifepo4 batteries
third party charger for those batteries on 110v
second third party charger on 110v but setup for generator. ie, usually unpowered but gets turned on sometimes.

The mains goes down a lot.

I’m thinking of putting in 3 shunts. A shunt from battery to my loads, a second between the battery and the main charger, and a third to the secondary charger.

Cerbo GX at the core of the system.

MPPT/Solar also charging batteries.

I just don’t know how the multiple shunts will present in VRM and if it’ll give me the data I want. A key part of this is getting a VRM notification when the mains goes down, ie that shunt stops getting power.

unfortunately, victron doesn’t offer up 110v AC chargers that suit, the largest (with ve.direct) being ~500W. And the EMxx AC sensors are more expensive than the shunts.

Thoughts? Anyone have something similar with multiple shunts they might share a screenshot of their VRM page for?

Thanks.

2

@syadnom
As a question. What role is each shunt playing?
Is one for SOC or all as DC meters? Or one for main SOC and the rest as meters?

You can have them all show on the main vrm screen (one if it is the battery monitor in the usual box.) the rest as boxes near the bottom of the page or as has dc system box. It depends on how they are configured.

3

MPPT>Shunt>Battery, so state of charge and consumption on this one. ‘normal’ configuration.

Charger1>Shunt>Battery, basically just charge metering and some notification if it loses volts on the charger side.

Charger2>Shunt>Battery, same as charger 1, but role is ‘is there a generator running or not’ and ideally send a notification when it stops. indicating fuel is low. This isn’t an auto-start generator, this is for when I have to send a tech to the site and hook one up.

4 
flowchart TD
    subgraph System1[Electrical]
        G1[Grid] --> C1[Charger 1]
        C1 --> S1[Shunt 1<br>DC Meter]
        S1 --> S3[Shunt 3<br>Battery SOC]
        S3 <--> B1[Battery Bank]
        C2[Charger 2] --> S2[Shunt 2<br>DC Meter]
        G2[Generator] --> C2
        S2 --> S3
        S3 --> L[Loads]
        M1[MPPT] --> S3
        P1[Solar] --> M1
    end

    subgraph Communication["Communication"]
        S1 <-->|VE Direct| Cerbo[Cerbo GX]
        S2 <-->|VE Direct| Cerbo
        S3 <-->|VE Direct| Cerbo
        M1 <-->|VE Direct| Cerbo
    end
5

Is this what you are describing?
i am not sure about the shunt when used as a DC meter is able to alert you the way you want it to, i have never tried it like that.

6

yeah, that’s basically it.

obviously I can just hook the stuff up, but I really love the monitoring that I have on all my solar sites.

This one is slightly different in that it’s a mains powered site but with 1000+ outages this year, so I’m going heavy on battery and a couple of solar panels. adding the AC component with victron is a real hassle especially when I want to be able to charge from generator at >1000W.

7

actually, that’s incorrect. here’s the layout. ie, shunt3 isn’t in series with shunt1 or shunt2. I don’t think it needs to be that way.

Screenshot 2024-09-12 at 3.55.30 PM
Screenshot 2024-09-12 at 3.55.30 PM814×730 40.9 KB

8

You wont be able to have an accurate SOC connected like that.
See the shunt install manual connections for SOC. It has to be the only thing by the battery negative. Nothing can be connected inbetween. It will have to be a DC meter only.
Or all sources of charge connect to one side of one shunt.
I have yet to work out how to do that in the mermaid diagram…might add a bus bar.
As a side note. The cerbo only has 3 ve direct to ve direct ports for connections. So one will need to be ve direct to usb or you could use a can connected mppt.

10 
flowchart TD
    subgraph System1[Electrical]
        G1[Grid] --> C1[Charger 1]
        C1 --> S1[Shunt 1<br>DC Meter]
        S1 --> Bus[Bus Bar]
        C2[Charger 2] --> S2[Shunt 2<br>DC Meter]
        G2[Generator] --> C2
        S2 --> Bus
        Bus --> S3[Shunt 3<br>Battery SOC]
        S3 <--> B1[Battery Bank]
        Bus --> L[Loads]
        M1[MPPT] --> Bus
        P1[Solar] --> M1
    end

    subgraph Communication["Communication"]
        S1 <-->|VE Direct| Cerbo[Cerbo GX]
        S2 <-->|VE Direct| Cerbo
        S3 <-->|VE Direct| Cerbo
        M1 <-->|VE Direct| Cerbo
    end
1 Like
11

ah, yeah, that makes sense. I need all my ‘extra’ shunts to be on the load side of the SOC shunt for it to accurately show SOC.

12

Correct, since you wanted them to measure your charge sources.