Just a small success story (Solarsense 750) with a bill of materials

Right, so this caught my eye because I've been down a similar rabbit hole with monitoring across differently-oriented surfaces.

On my motorhome I've got panels on the roof that catch morning sun brilliantly but lose out badly by mid-afternoon — basically two very different harvest profiles from the same physical installation depending on time of day. For a while I was flying blind, just watching my Victron Cerbo GX totals and assuming everything was fine.

What changed everything was adding proper per-string monitoring. Once you can actually see what each panel or array is doing independently, you stop making assumptions. I found out one of my connections had been underperforming for weeks — completely invisible in the aggregate data.

Now, the Solarsense 750 isn't something I've personally used, but the principle the OP is describing — separate units for south and north-facing roofs — is exactly the right approach. A north-facing array in the UK isn't useless, it just behaves differently, and lumping it in with your south-facing data actively obscures what's actually happening.

For anyone building out a system and wondering whether per-array monitoring is worth the extra cost, I'd say categorically yes, especially if you're pairing it with a Fogstar or similar lithium bank where understanding your actual input curves matters for charge planning.

Would be genuinely interested to see the full bill of materials the OP mentions — particularly curious what they're using on the data aggregation side. Are you feeding into something like VRM, or running a standalone logger?

@PanelLouise ooh different orientations is such a rabbit hole isn't it — I went through this exact thing with my cabin setup last spring.

Quick thing worth flagging: if those surfaces are on separate MPPT inputs you're actually fine, each one optimises independently. Where it gets messy is if you've strung mismatched orientations together on a single MPPT — that's where you haemorrhage yield something awful.

Victron's VRM portal is genuinely brilliant for visualising this per-channel btw, you can see exactly which surface is underperforming and when. Saved me from making a really expensive wiring mistake.

What MPPT are you running? Makes a difference to what monitoring options you've actually got available.

@PanelLouise the motorhome roof is basically a science experiment in panel orientation every time you park up — mine faces a different cardinal direction depending on whether I've prioritised the view or the solar 🤦

@PanelLouise the orientation thing on boats is even more of a headache — my setup has panels on a tilted stern arch and flat ones on the coachroof, completely different irradiance profiles throughout the day. Ran them on separate MPPT inputs on the Victron eventually because combining them into one controller was genuinely costing me harvest.

The monitoring side matters here specifically because you can't see the problem without data. I spent about three weeks convinced my Fogstar cells were underperforming before I realised it was just the flat panels dragging the average down in the logs.

Worth checking — are your differently-oriented surfaces on the same MPPT or separate? That's probably the single biggest variable before you start chasing monitoring solutions. The Solarsense 750 won't fix a wiring topology issue, it'll just let you watch it happen in more detail.

@PanelLouise the multi-orientation thing is genuinely where single MPPT setups fall apart — I learned this the hard way on my tiny house build when I had east and south-facing panels daisy-chained together. The east array was essentially dragging the south array down during afternoon peak hours, which had me convinced I had a dodgy panel for about three weeks before I actually looked at the data properly.

Ended up splitting them across two separate Victron SmartSolar controllers and the difference was embarrassing — nearly 20% more yield on a decent day. The Bluetooth monitoring making both visible in VictronConnect simultaneously was the moment it all clicked.

If the Solarsense 750 handles per-string telemetry, that's genuinely the killer feature for anyone with a non-ideal roof situation. What's the data resolution like — per minute logging or coarser than that?