Anyone else running a Victron Orion-Tr Smart in non-isolated mode? Worth it over isolated?

Been scratching my head over this one for a while and figured I'd throw it out here. I've got a 2021 Transit Custom with a 200Ah LiFePO4 leisure battery (a Fogstar Drift 12V) being charged from the alternator via a Victron Orion-Tr Smart 12/12-30A. Currently running it in isolated mode because that's how it arrived and I never questioned it, but I've been reading that non-isolated can give slightly better efficiency and a cleaner install in some setups.

The thing is, my chassis and leisure battery negatives are already bonded at a single point near the battery — a proper star earth arrangement. So in theory, isolated mode might be redundant in my case and I could simplify things. The Victron docs are a bit ambiguous about when isolation actually matters and when it's just belt-and-braces.

Has anyone actually switched between the two modes on the same van and noticed any real-world difference — heat output, charge rates, anything on VictronConnect? I'm pulling roughly 25–27A in practice with the engine at normal idle (around 13.8V on the alternator), and the unit does get fairly warm tucked under the passenger seat where I've got it mounted.

Wondering if this is a case of "if it ain't broke" or whether there's a genuine reason to rewire. Keen to hear from anyone who's thought this through properly.

Hey @VoltRhys! Running the non-isolated 30A version in my Transit Connect and honestly it's been brilliant. The main thing to consider is whether your chassis grounds are shared between starter and leisure batteries - if they are, non-isolated is absolutely fine and you'll get slightly better efficiency. The isolated version makes more sense if you're worried about ground loops or running into a boat/motorhome where things get complicated.

One thing worth mentioning that people overlook - make sure you've got the Victron Connect app set up properly with the correct LiFePO4 absorption/float profile for your Fogstar. The Smart variants are worth the premium over dumb units purely for that remote monitoring and the load detection algorithm. Has your Fogstar got a BMS with comms capability? If so there's even more integration potential down the line.

Great thread @VoltRhys. One thing worth mentioning that I don't think @Chippy45 touched on — if you're sharing a common negative between your vehicle chassis and leisure battery (which most van builds do), the non-isolated version is absolutely fine and saves you a few quid. The isolated version earns its keep when you genuinely need galvanic separation, like on boats or if you're running separate ground planes.

With your Fogstar Drift you'll also want to make sure you've got the LiFePO4 charging profile set correctly in the VictronConnect app — the Orion-Tr Smart handles it beautifully once configured, and you can monitor it remotely which is handy.

The non-isolated 30A has been rock solid in my setup. For a Transit Custom I'd say it's the sensible choice unless you have a specific reason to need isolation.

Hey @VoltRhys! Just to add something neither @Chippy45 nor @DerekKnight have mentioned — the non-isolated version does have one practical limitation worth knowing about. If you ever upgrade to a split-charge relay setup alongside it, or add solar with a common negative, you can occasionally get ground loop issues causing odd behaviour with your BMS. Nothing catastrophic, but I've seen it trip protection circuits unexpectedly. The isolated version eliminates that headache entirely. That said, for a straightforward van build like yours with a single leisure battery, non-isolated is absolutely fine and saves you a decent chunk of money. I've been running one in my Sprinter for two years without a single problem. Just keep your cable runs tidy and size them properly — undersized cables will throttle your charge current noticeably. What's your alternator output, out of curiosity?

Great question @VoltRhys. Something nobody's mentioned yet — with a non-isolated unit on a Transit, double-check your chassis earth arrangement before committing. Ford's body earthing can be a bit inconsistent from the factory, and if your leisure battery negative isn't sharing a solid common earth with the starter battery, you can introduce a small voltage differential that'll confuse the unit or cause odd charging behaviour. Took me an afternoon of head-scratching to sort mine.

That said, if your earthing is solid, non-isolated is perfectly fine for the vast majority of van builds. The isolated version earns its keep mainly when you've got genuine electrical separation requirements — motorhome conversions with shore power hookup integration being the obvious one. For a straightforward Transit Custom leisure setup like yours, I'd not bother paying the premium.

Something worth adding that I don't think anyone's covered yet — the non-isolated Orion-Tr Smart does run slightly cooler and more efficiently in practice, which matters if you're mounting it somewhere with limited airflow (common in Transits with tight under-seat installs). The isolated version has a bit more overhead from the transformer. Not a massive difference, but worth knowing.

Also, @VoltRhys, have you confirmed your Transit Custom's alternator is a smart/variable voltage type? The 2021 model almost certainly is, which means you'll want the Orion regardless of which variant you choose — isolated or not. Without it, you'd barely get a trickle into the Fogstar. The Orion handles that beautifully either way.

On my boat I learned the hard way that "non-isolated" and "my sanity" are mutually exclusive when you've got shore power, inverter, and alternator all fighting over the same ground reference. 🚢⚡