Monitoring a 3rd and 4th battery bank

Been thinking about this a lot lately as my setup is getting more complicated.

Currently running a 24V Fogstar Drift lithium bank on the boat with a Victron Multiplus-II, Cerbo GX and a SmartShunt handling monitoring — works brilliantly. But I'm now looking at adding a separate service bank for the garden office (different chemistry, possibly a cheaper AGM setup to keep costs down), and potentially a third bank purely for the windlass and bow thruster.

My question is: how are people handling monitoring across three or four separate banks in VRM?

From what I understand, you can daisy-chain additional SmartShunts via the VE.Direct ports on the Cerbo, but there are only so many ports available. Has anyone actually done this in practice? Does VRM display each bank cleanly as a separate entity, or does it get messy?

Also wondering whether the VE Bus BMS NG causes any complications when you're trying to monitor auxiliary banks that aren't connected to it — does it interfere with anything?

• Are extra VE.Direct to USB adapters a reliable workaround?
• Anyone using a GX Tank 140 or similar to free up ports for other things?

Feels like Victron's ecosystem is almost too flexible sometimes — there are five different ways to do everything and half the forum threads contradict each other.

Anyone running a comparably complex multi-bank setup on a boat or similar space-constrained install? Would love to know what actually works in the real world rather than what looks good on paper.

Hey @GrumpyWarden, interesting setup! One thing worth looking at is adding additional SmartShunts for each extra bank - they'll all talk to the Cerbo GX over VE.Direct and show up neatly in the overview. You're limited to a handful of VE.Direct ports on the Cerbo though, so if you're running out you might need a USB hub with VE.Direct to USB cables.

The trickier bit is making sure your GX device actually distinguishes between them properly in the dashboard - you can rename each shunt in the settings which helps no end. What's the purpose of the additional banks, starter battery monitoring or full secondary house banks? That'll probably affect which route makes most sense for you.

@NotAnElectrician48 has the right idea with extra SmartShunts — but worth knowing the Cerbo GX can only display two battery monitors natively on the dashboard. Third and fourth banks still show up in the device list, they just don't get the nice summary tiles.

Workaround I use on my narrowboat: Node-RED on a Venus OS large image pulls all the data and I display it on a separate touchscreen. Bit of faff to set up initially but rock solid once it's running.

Also worth checking if your additional banks actually need individual shunts — if they're being managed by separate MPPTs or a Lynx Distributor, you might already have decent data without adding more hardware.

What's the third/fourth bank for? Starter battery? Engine alternator side?

@PanelGraham is correct on the two-shunt limit for native display — but don't let that stop you, @GrumpyWarden.

The workaround is Node-RED on the Cerbo, which lets you pull in additional SmartShunt data and display it however you like. I've done exactly this on my narrowboat to track a separate starter bank and a dedicated EV charging buffer bank.

Alternatively, VictronConnect can see all paired SmartShunts via Bluetooth independently — not elegant, but functional if you're not permanently aboard.

Worth also considering whether you actually need individual shunts or whether your BMS telemetry covers you adequately for the Fogstar banks.

What's the third and fourth bank for — different voltages, different purposes? That changes the answer significantly.

Been down this exact rabbit hole with my own expanding setup. What nobody's mentioned yet is that if you're pulling this into VRM, you've got a lot more flexibility than the Cerbo's local display suggests — you can build custom dashboards that pull in additional SmartShunt data and display it however you like.

Also worth considering whether all those banks need individual shunts, or whether your BMS comms are doing enough of the work already. My Fogstar Drift talks to the Cerbo directly over its BMS connection, so I'm not doubling up with a shunt on that one — saves a slot for monitoring something that genuinely needs it.

What's the fourth bank actually doing? Starter battery, bow thruster, something else? That context changes the answer quite a bit.

@GrumpyWarden this is basically where I ended up when I started daydreaming about adding a second bank to my static caravan setup — the rabbit hole goes deep fast, doesn't it?

Quick question nobody's directly answered yet: are you planning to monitor all four banks from a single Cerbo dashboard, or are you happy with Node-RED / VRM doing the heavy lifting for banks 3 and 4?

Because those are quite different problems. The hardware side (extra SmartShunts) is relatively straightforward. It's the display and alerting side where it gets messy.

Also — what are banks 3 and 4 actually for? Separate loads, separate charge sources, or just capacity expansion? That changes the monitoring strategy quite a bit before you start throwing kit at it.