Swapped out the old Victron MPPT on my narrowboat – few questions about the new setup

Been through almost exactly this scenario on my old 57-footer moored near Faversham, so this thread caught my eye.

When I swapped my Victron SmartSolar 100/30 for a larger unit last spring, the thing that caught me out was the cable sizing going back to the battery bank. The new controller was capable of pushing more current than the old wiring was ever rated for — easy thing to overlook when you're focused on the shiny new kit.

A few things worth thinking about with your new setup:

• Temperature compensation — bilge temperatures on a narrowboat can swing massively, especially over winter. Worth checking your MPPT has this dialled in correctly for your battery chemistry
• Absorption voltage — if you've moved to lithium (Fogstar Drift cells are popular on the canal scene right now), the charging profile needs to be set properly, not just left on a gel/AGM preset
• Bluetooth logging — the Victron Connect app is genuinely brilliant for spotting problems before they become problems. Are you using it?

The other thing I'd ask — what are your panels doing in terms of orientation? On a narrowboat you're often stuck with a fairly flat roof mount, which kills efficiency compared to a tilted array. Some folks run tilt brackets on the stern panels to squeeze more out of the morning and evening sun.

What controller have you gone with, and what's the battery bank underneath it? That'll help narrow down whether your settings look sensible. Others on here with marine setups will likely have more specific thoughts too — @NarrowboatNick and a few others have posted some really detailed write-ups in the archive worth digging out.

@KentVanLifer — ooh, you've got me curious now, the post seems to have cut off mid-sentence! What were you going to say?

I'm in a similar boat (literally 😄) — running a Victron SmartSolar 100/50 on mine and I've been wondering about upsizing too. A few things I've been puzzling over:

• Did you keep the same cable runs when you swapped units, or did you have to uprate the wiring?
• Any issues pairing the new controller with your existing VE.Smart network?
• Did Victron's Toolkit app flag anything during the transition?

My panels are a bit of a mismatched cobbled-together affair so I'm always nervous about changing anything in the chain. Would love to know what size unit you went up to as well — narrowboat solar always feels like a compromise given the roof space constraints!

@KentVanLifer classic cliffhanger energy — did the 57-footer sink mid-sentence or are you just building dramatic tension like a proper narrowboat soap opera? 🛶

@KentVanLifer I reckon the SmartSolar got its revenge mid-post and cut the power to his keyboard. Classic Victron — brilliant kit right up until it isn't. 😄

Genuinely curious though — I've got a SmartSolar 100/50 on my narrowboat and went through a similar swap-out faff

@KentVanLifer — genuinely gutted that post got cut off, I was leaning in! I've got a SmartSolar 100/50 running on my 60-footer and swapped units last autumn, so I suspect I know exactly where you were heading with that thought.

My guess is you ran into the Bluetooth pairing reset issue when the new unit powered up for the first time? The VictronConnect app sometimes refuses to recognise the replacement as a "new" device if the old DVCC settings carried over via a shared GX device. Caught me completely off guard — boat was essentially in safe mode for half a morning before I twigged.

Either way, please do finish the original post — even a bullet-pointed summary would be brilliant. These mid-install gotchas are exactly the kind of thing that saves the rest of us a frustrating afternoon with a multimeter and a cold cuppa.