Anyone else running Victron SmartSolar on a van? Curious what MPPT size you went for

Just finished fitting a 200Ah Fogstar Drift lithium under the bed in my Transit. Paired it with a 175W panel on the roof and a Victron SmartSolar 100/20. Seems to be working well so far but wondering if I undersized the MPPT — on a cracking day I'm seeing maybe 140W peak coming through.

The 100/20 should handle up to 290W on a 12V system so there's room to add another panel. Thinking about squeezing a second 175W on there before summer. Anyone done a similar setup and noticed meaningful gains from the extra panel, especially in the shoulder seasons?

Also not sure whether to go series or parallel for two panels on a van roof. Shading is a real concern with a rooflight in the way.

@BatterySam nice setup — the 100/20 should handle that 175W panel comfortably, you've got headroom too if you ever want to add a second panel later.

Quick question though — are you running the SmartSolar via Bluetooth only or have you picked up the Cerbo GX as well? I'm trying to decide whether the full GX monitoring setup is worth the extra cost for a single-panel install like mine, or whether just using the VictronConnect app is sufficient day-to-day.

Also curious what charge profile you've set for the Fogstar — I've seen people debate whether to use the Victron lithium preset or dial in custom absorption/float voltages manually for better longevity.

Nice one @BatterySam, the Fogstar Drift is a cracking choice for van life — handles partial state of charge really well which is ideal for touring.

I'm running a 100/30 on my Sprinter with two 175W panels in series, feeding into a 200Ah Epoch lithium. The jump to the 30A controller was worth it for the extra headroom, and the price difference from Victron is minimal. Definitely worth considering if you ever go down the twin panel route.

One thing I'd strongly recommend is getting the SmartSolar connected to the VictronConnect app via Bluetooth — the battery monitoring data is genuinely useful and you can fine-tune the absorption/float settings to suit lithium properly. Makes a big difference knowing exactly what your system's doing.

@BatterySam worth double-checking your actual panel Voc against your controller's input limits before adding more panels down the line. The 100/20 accepts up to 100V input, so you've got decent headroom on voltage, but the 20A output cap is your real ceiling — roughly 280W max from a 12V bank before you're clipping.

Running a similar Victron SmartSolar setup in my shepherd's hut off-grid (different application but same kit), and the VictronConnect app is genuinely useful for monitoring yield history and tweaking charge parameters for lithium — make sure your absorption and float voltages are set correctly for the Fogstar's BMS spec rather than leaving it on the default lithium preset, as those can vary.

Great setup @BatterySam! One thing worth mentioning alongside what @Macca64 said about Voc — if you're thinking of expanding later, also keep an eye on the 100/20's maximum input wattage for your battery voltage. Running 12V, you're limited to around 240W input, so a second panel would put you right at the edge. If expansion is on the cards, it might be worth considering whether the 100/30 would've given you more breathing room. That said, for a single 175W panel it's absolutely fine and you'll rarely see genuine rated output in UK conditions anyway! How are you finding charge times on overcast days? I've got a similar setup in my Sprinter and honestly the Victron's absorption stage seems to squeeze out every last bit even on grey days.

Running a 100/30 on my narrowboat with 300W of panels — future-proofing the controller is the cheapest upgrade you'll ever do when you're already elbow-deep in the install. 🚤