Adding solar to BMS 12/200

Running a similar setup in the motorhome — twin Fogstar Drift 200Ah lithiums with a Victron Smart BMS 12/200 — and the solar question is one I keep circling back to.

At the moment I've got a Renogy 200W panel feeding directly into a Victron SmartSolar MPPT 100/30, which then goes to the battery bus before the BMS. Works fine on the road, but I've started wondering whether I should be running the MPPT output through the BMS load side instead, particularly once I wire in a MultiPlus 12/1600 over the winter.

The BMS 12/200 is brilliant for protecting the cells, but the manual is about as clear as a British summer when it comes to solar integration — specifically around what happens if the BMS trips and you've still got panels pumping current in.

A few things I'm trying to get my head around:

• Does anyone have their MPPT tail-end connected to the BMS "Load" output rather than direct-to-battery?
• Is the VE.Smart networking actually doing useful coordinated charging when solar + MultiPlus are both active, or is it more "polite suggestion" territory?
• Anyone running a Cerbo GX for full system visibility — worth it for a motorhome rig, or overkill?

The sailboat crowd seem well ahead of us on this stuff — those lads have figured out setups we van and motorhome types are still scratching our heads over.

Curious what wiring decisions others have landed on. Drop your diagrams if you've got them — blurry phone photos of cable spaghetti absolutely accepted.

@SolarRob the solar question that never ends! 😄

Right, so the BMS 12/200 doesn't handle solar directly — it's purely for load and alternator control. Your MPPT needs to connect straight to the battery terminals, not through the BMS. Victron's own SmartSolar controllers will then chat nicely with

@SolarRob worth noting the BMS 12/200 is essentially just a load disconnect and alternator management device — solar needs its own MPPT going straight to the battery terminals. A Victron SmartSolar talking to the BMS via VE.Smart networking is the cleaner approach; the MPPT backs off when the BMS signals high cell voltage rather than relying on any direct wiring between them.

What I'd be cautious about is people wiring solar through the BMS load output — it's not designed for charge current in that direction and you'll likely cause issues long-term.

What MPPT are you currently running or looking at? Sizes matter here depending on your panel array.

@SolarRob hook your MPPT straight to the battery terminals — the Victron SmartSolar will talk to the BMS via the VE.Smart network and throttle itself back when the BMS cries uncle, which is exactly how mine's wired in the garden office and it's been rock solid for two winters.

@DuctTapeDave is spot on with the VE.Smart networking — once you've got your SmartSolar chatting to the BMS it's like they've known each other for years. Unlike my neighbour and his generator, which just argue constantly.

One thing worth adding: make sure your MPPT is sized properly for the battery bank. Twin 200