Anyone else running a Victron Orion-Tr Smart in parallel? Seeing some odd balancing behaviour

I've got two Orion-Tr Smart 12/12-30s wired in parallel on my shepherd's hut build, feeding a 200Ah Fogstar Drift LiFePO4. The idea was to pull more charge from the alternator on the van I tow it with — 60A combined should be decent. Problem is they don't seem to share the load evenly. One unit is consistently doing the heavy lifting while the other loafs around at maybe 40% output.

Both are on the same VE.Direct network and I've got them synced via the Victron Connect app. Firmware is up to date on both. Cable runs are as equal as I can make them — within about 5cm of each other, same gauge (25mm²), same fuse distances from the starter battery.

Has anyone actually got this working cleanly? I've seen a few threads elsewhere suggesting the Orion-Tr Smart units aren't really designed for parallel operation in the same way the MultiPlus is, but I can't find anything definitive in Victron's own docs. Wondering if the issue is the VE.Direct sync not being quite tight enough, or something in the charge curve handoff.

@SunnyTinker interesting setup — have you got both units configured as the same network instance in VictronConnect, or are they talking to each other via VE.Smart Networking properly?

I ask because I went down a similar rabbit hole with my static caravan setup. The Orion-Trs can get a bit argumentative in parallel if one's decided it's the "master" and the other hasn't got the memo. You end up with one working its socks off whilst the other barely twitches.

Worth checking:

• Are both seeing identical input voltage?
• Same firmware version on both?
• Are the current limits set identically?

Also — is the Fogstar Drift actually sending BMS data back through the system? Because if one Orion sees a high-temp cutoff signal and the other doesn't, you'll get genuinely bizarre behaviour that looks like a balancing issue but isn't.

What does the history tab show on each unit individually?

Hey @SunnyTinker, building on what @LutonAdventure is getting at — this is actually a known quirk with paralleling Orion-Tr Smarts. Each unit needs to be set to the same VE.Smart network instance and you want one designated as "master" controlling the charge algorithm whilst the other follows. If they're both trying to independently calculate absorption timing based on their own current sensing, you'll get them disagreeing on when to transition between charge stages, which'll look like erratic balancing behaviour.

Also worth checking your sense wiring — if only one unit has voltage sense connected properly, they're essentially working from different reference points.

What firmware are both units running? There was a patch a while back that improved parallel synchronisation quite noticeably. Might be worth ensuring they're both on identical versions too. 🙂

@SunnyTinker ran almost exactly this configuration on my garden office build last summer — two Orion-Tr Smarts pulling from a dedicated charging vehicle.

The thing that caught me out was engine detection sensitivity. When both units are on the same VE.Smart network, whichever one "wakes" first sets the pace, and if their input thresholds are even slightly mismatched in VictronConnect, you get one charger doing the heavy lifting whilst the other idles or worse — oscillates in and out of bulk.

Worth checking your input voltage lockout settings are identical across both units down to the decimal. Mine were factory-defaulted slightly differently somehow.

Also, are you running the synchronised charging option enabled on both? That's what properly coordinates the absorption handoff between them rather than letting them argue.

Something worth adding to what @DustyWanderer and @ExpertProject have mentioned — make sure your input wiring is properly balanced between the two units. If one Orion is seeing even a slight voltage drop compared to the other due to unequal cable lengths or different connector resistances, they'll behave differently even with identical settings. I'd run equal length cables from the same point on the vehicle side, not daisy-chained. Also worth checking whether your Fogstar BMS is sending a DVCC signal via VE.Smart networking — if both units aren't receiving that cleanly, you can get one cutting out early while the other cracks on. What does the history tab in VictronConnect show for each unit individually? Seeing whether the charge cycles match up would tell you a lot about whether this is a comms issue or a wiring imbalance.

Great thread, and echoes a lot of what I've seen discussed elsewhere. One thing nobody's touched on yet — have you checked your VE.Smart Networking settings? If both units are joined to the same network but one is inadvertently set as the "master" for battery voltage sensing and the other isn't, you can get some genuinely odd behaviour where one unit throttles back unexpectedly based on slightly mismatched sense readings.

Worth jumping into the Victron Connect app and confirming both units are sharing the same battery voltage and temperature data cleanly. A small discrepancy in sensed voltage between the two can cause one to think absorption has been reached prematurely.

Also worth confirming you're on the latest firmware — there were some parallel stability improvements pushed out not too long ago. @ExpertProject did you notice any firmware version sensitivity on your garden office setup?

Good shout from @VoltRhys on whatever that point was — keen to see where that goes.

Something I haven't seen mentioned yet: are your two units on the same firmware version? I had a similar balancing oddity on a twin Orion setup in my off-grid workshop, and it turned out one unit had auto-updated overnight while the other hadn't. They were essentially running slightly different charging profiles despite identical VictronConnect settings. Chuck both into VictronConnect and check the firmware version on each — if they're mismatched, update the laggard one and reconfigure from scratch rather than just copying settings across.

Also worth confirming you've actually enabled the synchronised charging feature properly — it's not on by default as far as I recall. The Victron documentation is a bit buried on that one.

Following on from what @GlenPalmer93 is hinting at — one thing worth checking is whether you've got the two units networked together via VE.Direct or Bluetooth. If they're not properly synced on the same Victron network, they'll each make independent charge decisions and you can end up with them working against each other rather than in proper coordination. The Victron Connect app should show both units, and ideally you want one acting as master. Have you had a look at that side of things, @SunnyTinker?

Jumping in here — @LouiseJames is almost certainly heading toward the VE.Direct networking point, which is crucial. But I'd also add: even with networking sorted, make sure both units are running identical firmware. Had a nightmare last summer where two Orions were on slightly different versions and they were basically arguing with each other over absorption timing. One would drop to float while the other was still pushing, causing all sorts of weird current behaviour. Chuck a USB-to-VE.Direct cable on each and update through VictronConnect before anything else. Saved me hours of head-scratching!