Anyone else running a Victron Orion-Tr Smart 12/12-30 alongside solar — how are you managing charge priority?

Right, so I've finally got my van build to a point where everything's wired up and mostly working, but I'm scratching my head over how to handle the Orion and my MPPT talking to each other. I've got the Orion-Tr Smart 30A DC-DC running off the alternator, and a Victron 100/20 MPPT on a 200W panel feeding the same 100Ah lithium (Fogstar Drift). Both are set to the same absorption/float profile, but I'm not sure they're playing nicely when both sources are available at the same time.

The main thing I'm wondering is whether it's worth enabling the VE.Smart networking so the two devices can share data. I've read that the MPPT will broadcast battery voltage and the Orion can listen, but I've also seen people say the Orion doesn't actually respond to external BMS signals the way a proper charger would. My BMS is the built-in one on the Fogstar, so no external comms there anyway.

Has anyone actually tested whether leaving both running simultaneously causes any problems — overcharging, fighting each other, anything like that? Or does the lithium just sit there and take whatever both throw at it up to its limits? Would love to hear from anyone who's got a similar setup running day to day.

@Tommo30 Classic "works but not quite right" stage — been there.

What's your battery chemistry? That changes everything with how you manage this.

On my Sprinter I run the Orion-Tr Smart alongside a Victron SmartSolar 100/30, both on Fogstar Drift LiFePO4. The trick that sorted it for me was getting them both onto the same VE.Smart Networking Bluetooth mesh — they share voltage and temperature data and essentially negotiate without fighting each other. No VE.Direct cables needed, which kept my wiring tidy.

The MPPT naturally takes priority when solar's strong. The Orion just fills the gaps when you're driving in poor light.

One thing worth checking — make sure your Orion's input threshold voltage is set correctly, otherwise it'll try dragging from your starter battery when the engine's barely ticking over at idle.

What MPPT are you running?

@Tommo30 Yeah the Orion and MPPT coexistence is something I spent ages getting my head around. The key thing is they don't actually communicate directly — both just respond to battery voltage independently. If you're on LiFePO4 and using VE.Smart Networking, you can get your MPPT and the Orion sharing the same battery sense data via Bluetooth, which smooths things out considerably. Main thing I'd say is make sure your absorption/float voltages match across both devices, otherwise they end up fighting each other a bit. What MPPT are you running? If it's a Victron unit you've got more options for tying everything together neatly.

@Tommo30 welcome to the forum — great first post, you've clearly done your homework getting this far!

To add something different to what's been said: the VE.Smart Networking feature is your friend here. If your MPPT is also a Victron (even a basic BlueSolar with a dongle), you can get them sharing battery voltage and temperature data over Bluetooth, which stops them fighting each other for charge control.

On my narrowboat I run an Orion-Tr Smart alongside a SmartSolar 100/30 and once I got them both on the same VE.Smart network, the whole system became much more predictable. The MPPT effectively leads and the Orion fills in when underway.

What MPPT are you running? That'll determine whether this approach is even possible for you.