Spent £340 on a second-hand Victron system — here's what I actually got

Last spring I picked up a job lot from a bloke in Bristol who was breaking up his narrowboat fit-out. Victron SmartSolar 100/30, a BMV-712 battery monitor, and a battered MultiPlus 12/800. Total came to £340 cash. The MPPT and BMV were basically spotless, the MultiPlus had a dented case but fired up first time on the bench.

Paired it with two Fogstar Drift 100Ah LiFePO4 cells I'd already got, and suddenly the garden office had a proper system rather than the cobbled-together mess it was before. Running a laptop, a few LED strips, a small fan heater on low — it handles a normal working day without drama as long as we get a few decent hours of sun through the 400W of Renogy panels on the roof.

The thing nobody tells you is that second-hand Victron is almost always worth it. The gear is built like a tank and the firmware updates keep coming even on older units. That SmartSolar is from 2019 and it's on the latest VictronConnect firmware right now, still pulling accurate MPPT data.

Anyone else gone the second-hand route for the core components? Curious whether people draw a line anywhere — batteries feel like a different risk to charge controllers, for instance. Would you buy a used LiFePO4 if the BMS history was unknown?

Julie1972 | 847 posts | ⭐ Trusted Member

@CallumHobbs ooh that's a proper find! Narrowboat break-ups are genuinely one of the best sources for second-hand Victron kit — those systems get well looked after because people's livelihoods depend on them. The MultiPlus 12/800 is the one I'd want checked over first though, particularly the transfer relay. They can get a bit iffy if the boat was doing a lot of shore power switching. Worth running VictronConnect on it and having a good look at the fault history if there is one logged. The SmartSolar and BMV-712 are pretty bulletproof in my experience. Did the bloke have any documentation with it, or know the age of the units? You can sometimes trace manufacture dates through Victron's serial number lookup which helps you know what you're actually dealing with. Looking forward to hearing the full breakdown of what you paid for each piece! 🙂

HighlandDweller | 1,203 posts | ⭐ Trusted Member

@CallumHobbs Narrowboat kit is often surprisingly well-maintained — those liveaboards tend to be pretty serious about their electrical systems, space and weight being at such a premium. The 100/30 and BMV-712 are cracking bits of kit that'll serve you well for years. Main thing I'd flag with the MultiPlus is to check the firmware version before you do anything else — older units can behave oddly and a VE.Bus cable plus the free VictronConnect software will tell you everything you need to know. Also worth checking the fan spins freely and isn't clogged with dust or debris. Keen to hear the full breakdown of what condition everything was in! 👍

T6Solar | 634 posts

@CallumHobbs solid haul for £340. The BMV-712 alone is worth £80-90 used if it's calibrated correctly — worth checking the shunt connections and resetting the peukert exponent/charged voltage thresholds if you don't know the previous config.

Main thing I'd flag on the MultiPlus: pull the cover and check the capacitors for any bulging. Boat environments are damp and those units work hard. Also confirm the firmware version — older units sometimes need a MK3-USB interface to update, which you can usually borrow from someone local or hire for a few quid.

What batteries are you pairing it with? If you're starting fresh on cells the SmartSolar 100/30 will comfortably handle a decent 200Ah Fogstar Drift build at 12V.

CliffGazer | 412 posts

Worth noting the MultiPlus 12/800 specifically — that's the one people often overlook because it's the smaller unit, but for a boat application it's arguably ideal. Lower standby draw than the bigger models matters a lot on a narrowboat where you're not always running the engine.

One thing I'd double-check: pull the serial number on the SmartSolar and run it through Victron's Professional portal if you can get access. Some secondhand Victron kit has had its warranty registration transferred improperly or — worse — it's been flagged. Had a near-miss with a 75/15 I bought off eBay a while back.

@CallumHobbs did the previous owner give you any paperwork, even just a VRM login? That'd tell you the charge history and whether it's been pushed hard.

DanHughes | 287 posts

Great score @CallumHobbs. One thing worth checking on that MultiPlus — grab VE.Configure and pull the settings file off it before you do anything else. Previous owners sometimes leave custom transfer switch thresholds or charge profiles baked in that don't suit your setup, and if you're not aware they're there you can chase your tail for weeks wondering why things aren't behaving. Took me an embarrassing amount of time to figure that out on a second-hand unit I bought.

Also with the SmartSolar, check the Bluetooth is pairing cleanly via VictronConnect. Occasionally the older firmware needs updating before it'll play nicely with newer phones. Both jobs take twenty minutes and save a lot of head-scratching down the line.