Anyone else running a Victron Orion-Tr Smart in non-isolated mode? Seeing some odd behaviour when solar kicks in

So I've had a 30A Orion-Tr Smart (non-isolated, 12/12) running between my starter and leisure battery for a few months now. Generally it's been brilliant — charges the 200Ah LiFePO4 nicely from the alternator on longer drives. But lately I've noticed it cutting out intermittently when the solar kicks in at the same time. The Victron Connect app just shows it going into a "standby" state for no obvious reason.

My setup is a 200W panel going into a SmartSolar 75/15 MPPT, and both the Orion and the MPPT are on the same VE.Smart network. I wonder if the Orion is seeing the leisure battery voltage rise from the solar and deciding the battery's already full, even though it genuinely isn't — SOC is usually around 60-70% when this happens. The absorption voltage on the Orion is set to 14.2V and the MPPT can push the leisure battery up to around 14.0–14.1V in decent sun, so I can see why it might get confused.

Has anyone actually dug into the charge algorithm settings on the non-isolated version to sort something like this? I'm wondering whether tweaking the "charge detection" threshold or adjusting the tail current settings would help, or whether this is more of a known quirk with having both devices on the same VE.Smart network. Happy to share my full config screenshots if that helps.

Hey @BrambleHermit, yes I've seen similar! The Orion-Tr Smart in non-isolated mode can get a bit confused when solar is already holding the starter battery voltage high — it sometimes sees that elevated voltage and either throttles back or briefly disconnects, thinking the input conditions have changed.

Worth checking your input voltage thresholds in the VictronConnect app. I found tweaking the "start voltage" and "delayed start" settings helped mine settle down considerably. Also make sure your BMS isn't sending an absorption/float signal that's confusing things upstream.

One thing that caught me out — the non-isolated version is quite sensitive to common ground issues if your solar controller is also referenced to the same negative. Might be worth double-checking your earthing arrangement.

What solar controller are you running alongside it? That might help narrow things down.

Great thread @BrambleHamilton and @GlenLover. I had exactly this issue last summer on my van build. What sorted it for me was checking the input voltage thresholds in the VictronConnect app — specifically the "start voltage" setting. When solar was pushing the leisure battery voltage up, the Orion was seeing that reflected back through the non-isolated circuit and getting confused about which direction to charge.

Worth double-checking you haven't got a ground loop situation too. Non-isolated units share a common negative, so if your solar controller and Orion share grounds in an awkward way you can get some really weird feedback behaviour.

Have you tried enabling the "battery safe" mode and adjusting the absorption voltage to match your BMS settings? That combination made mine much more stable. What firmware version are you running? There were some fixes in recent updates.

Good thread this — I've been running the same setup on my narrowboat for about 18 months so hopefully can add something useful.

One thing worth checking that nobody's mentioned yet: have a look at your input voltage lockout settings in the VictronConnect app. If the solar is pushing your starter battery voltage above the Orion's default "engine detection" threshold (think it's around 13.2V), it can trigger some odd start/stop cycling because the unit keeps re-evaluating whether the engine is actually running.

I'd also suggest enabling the "allow to charge when BMS reports absorption/float" option if you haven't already — made a real difference for me when my MPPT and the Orion were effectively arguing over the LiFePO4.

@BrambleHermit what MPPT are you running on the solar side? Would help narrow things down a bit.

Hey @BrambleHermit — worth checking your VE.Smart Networking settings if you've got a BMV or SmartShunt in the mix. When solar pushes the leisure battery voltage up, the Orion can misread the source/destination relationship and throttle back or drop out entirely.

One thing that helped me was tweaking the input voltage lockout threshold in the Victron Connect app — bumping the "start voltage" up a touch so it's not constantly hunting. Also make sure your firmware is current; there were a couple of updates last year specifically addressing behaviour in shared-ground non-isolated setups.

@CallumHamilton83 touched on something important too — the cable run quality really does matter here. Any extra resistance on the input side will confuse the voltage sensing no end. What length are your cables running?