SolarSense 750 not visible in GX520

Ran into something similar when I added a Orion-Tr Smart to my van's VE.Direct network a while back — the GX device just flatly refused to acknowledge it existed, even though Victron Connect could see it no bother over Bluetooth.

The GX520 has a finite number of VE.Direct ports (two physical ones, if I recall correctly), and that's your likely culprit here. Once you've got the SmartSolar MPPT and the Battery Sense occupying those ports, the SolarSense 750 has nowhere to pipe its data to the GX — Victron Connect bypasses all that by talking directly over Bluetooth, which is why you can see it there but not on the display.

A few things worth checking:

• Are you using a VE.Direct to USB cable into the GX520's USB port? That can extend your device count if you haven't already tried it
• Firmware — both the GX and the SolarSense need to be reasonably current; older GX firmware had patchy support for newer devices
• VE.Smart Networking — this is a Bluetooth mesh between devices and doesn't automatically translate to GX visibility. Easy to confuse the two

Honestly, Victron's device compatibility matrix for the GX520 specifically isn't brilliantly documented. I spent an embarrassing amount of time staring at a blank device list before realising I'd simply run out of ports.

Anyone else had this with the SolarSense 750 in particular? Curious whether it's a firmware thing or a hard limitation on that GX model.

@GoldenNomad yeah the VE.Direct port limit catches people out constantly. The GX520 only has two physical VE.Direct ports, and once they're both occupied the device just silently disappears from the overview — no error, nothing. Drove me absolutely mental on my narrowboat build last winter.

Worth checking whether your SolarSense 750 is actually a VE.Direct device or if it supports VE.Can instead — because if it does, you can offload something onto the CAN bus and free up a port. Alternatively, Victron's USB-to-VE.Direct interface cables let you expand via the GX's USB ports, though I've had mixed reliability with those on 12V systems drawing from the same supply rail.

What else is currently occupying your VE.Direct ports?

@ForestBoater that's a really useful clarification on the port limit — is there a workaround if you've already used both ports? I'm thinking about my narrowboat setup where I might want to connect multiple devices to a single GX unit eventually.

Does the VE.Direct to USB cable help here, or is the USB interface on the GX520 equally restricted? I've seen mention of a VE.Can network as an alternative for some devices, but I'm not sure which Victron kit actually supports that protocol vs just VE.Direct.

Also wondering whether the SolarSense 750 specifically has VE.Can capability or if it's VE.Direct only — that might be the root issue @GoldenNomad is hitting rather than anything configuration-related.

@AshSeeker yes, there are a couple of decent options. The most straightforward is a USB to VE.Direct cable — the GX520 has USB ports which effectively give you extra VE.Direct connections beyond the two physical ones. You can daisy-chain several devices that way.

Alternatively, if your devices support it, VE.Can is worth considering for larger setups as it handles multiple devices on a single bus without the port limitations.

Worth noting though — the SolarSense 750 specifically, I'd double-check it actually has VE.Direct output rather than just VE.Direct input for programming purposes. Some MPPT controllers are a bit ambiguous in their specs on that point, which could be a separate issue from what @ForestBoater mentioned about port limits.

@Compo_7207 worth flagging that the USB route does work but you're limited to 5 VE.Direct USB devices total on the GX520 — people assume it's unlimited and then wonder why device 6 vanishes.

Also worth considering the VE.Can side of things if your SolarSense 750 supports it. Completely separate bus, doesn't eat into your VE.Direct allowance at all.

On my narrowboat I ran into this exact headache — ended up using a Cerbo GX instead which has 3 native VE.Direct ports plus the USB expansion. Bit of an outlay but saved a lot of faff.

One thing I'd double-check first though: is the SolarSense 750 actually VE.Direct compatible or just physically using the same connector? Not all third-party gear plays nicely regardless of the port situation.