Victron 24VDC + 12VDC system. Resetting only 12V

Been running a similar mixed-voltage setup on my narrowboat for a couple of years now, so this is something I've thought about quite a bit.

The cleanest solution I've found is using a Victron Orion-Tr Smart DC-DC converter between the 24V bank and the 12V side. This means your 12V loads are essentially isolated — you can cut power to just that circuit without touching the 24V system at all. Chuck a simple blade fuse or a small breaker on the 12V output side and you've got independent reset capability sorted.

What I'd be wary of is using a basic resistor or voltage divider approach — it's crude, inefficient, and causes no end of grief when load demands fluctuate, which on a narrowboat (or any off-grid setup) they absolutely will.

A few questions worth thinking through:

• What's actually on your 12V side? Lighting, water pump, 12V sockets?
• Are you running Fogstar or similar LiFePO4 batteries, and if so, does the BMS talk to the Victron ecosystem via VE.Bus or Bluetooth?
• Is the reset requirement for fault-clearing, or are you wanting scheduled cycling?

If it's purely fault-clearing, a Victron Battery Protect on the 12V rail is another solid option — you can trigger it remotely via the programmable input, which plays nicely with a Venus GX or Cerbo if you've got one in the system.

Genuinely curious what's driving the need to isolate just the 12V side — there might be a simpler architecture depending on your specific use case. What does the rest of the setup look like?

Great shout @OffGridTel, the Orion is a solid choice for that kind of setup. One thing worth adding though — if you're resetting only the 12V side, have a look at whether your 12V loads actually need a full reset or just a momentary drop. I've found on my own boat that a BatteryProtect on the 12V rail handles low-voltage disconnection independently without touching the 24V system at all. Means your 24V bank stays completely undisturbed whilst the 12V side does its thing. Victron's VE.Direct comms between the BatteryProtect and your MPPT or BMV makes the whole lot talk together nicely too. Saves a lot of faff!

Has anyone actually done this with a garden office setup rather than a boat? I've got a 24V Victron system feeding my office and I'm considering adding a 12V sub-circuit for some low-draw kit (12V lighting, a dashcam-style security camera, etc.).

My main question is — if the 12V side trips or needs resetting, does the Orion DC-DC just pick back up automatically once power's restored, or does it need manual intervention? That's the bit I'm unsure about before committing to anything.

Also wondering whether a Fogstar lithium pack would even make sense as a dedicated 12V buffer, or if that's overcomplicating things for relatively low loads.

Hey @MelKing83, yes! I've got almost exactly that setup in my garden office. 24V bank feeding a Multiplus, with a separate 12V leisure battery for some LED lighting and a couple of USB charging points I wired in early on before I'd thought it all through properly 😄

The key thing I'd add to what @OffGridTel and @PhilFox99 have said — make sure you're sizing the Orion correctly for your actual 12V load. It's easy to underestimate, especially once you start adding bits and pieces over time. I went for the 24/12-20A and it's been absolutely spot on for a garden office scale setup.

Also worth thinking about where you physically mount it — mine gets reasonably warm under sustained load so decent ventilation matters.

@MelKing83 worth noting that on a narrowboat the physical separation between your 24V and 12V banks actually helps mentally — you're forced to think of them as distinct systems. In a garden office that boundary is less obvious, which can lead to muddled fault-finding when something trips.

One practical tip: label your busbars clearly and document which loads sit on which rail. Sounds obvious but when you're resetting only the 12V side (as the thread title suggests), knowing exactly what's downstream of that rail saves a lot of head-scratching. I use a laminated wiring diagram cable-tied to the enclosure door.

Also consider whether your 12V loads actually need to be 12V — some equipment runs fine on a small Victron DC-DC converter dropping from 24V, which means one bank to manage rather than two.