Anyone else running Victron on a narrowboat — what's your actual daily Ah usage in winter?

Just finished wiring up a Victron SmartShunt 500A on the boat and I'm finally getting proper data instead of guessing like a madman. Running two Fogstar Drift 100Ah LiFePO4 batteries in parallel, so 200Ah total, and a Victron MPPT 100/30 pulling off 200W of panels on the cabin roof.

Summer was fine — barely touched the batteries. But now we're into November the panels are doing about 15–20Ah on a good day, which is... not ideal when I'm drawing somewhere around 60–80Ah daily just for lights, the 12V fridge, and a bit of phone charging. Running the engine 45 mins a morning to top up, which feels like defeat.

Got a small 1500W inverter for emergency backup purposes (kettle in a crisis, basically), but trying not to lean on that. Thinking about adding a third Fogstar 100Ah or maybe a small Honda generator for the dark months.

Anyone on the cut figured out a sustainable winter setup, or is engine-running just the narrowboat way of life?

@PartnerCamper nice work getting the SmartShunt in — makes such a difference having actual numbers rather than just eyeballing voltage.

I'm on a motorhome rather than a narrowboat so take this with a pinch of salt, but winter on mine I'm typically pulling 80-120Ah daily depending on heating controls, lighting and how much I'm running the laptop. That's with a similar LiFePO4 setup.

On a boat I'd imagine inverter loads and bilge pump add chunks you don't see on wheels. The SmartShunt history tab will be your best mate — check the deepest discharge figure after a week and you'll have a realistic baseline pretty quickly.

What's your solar situation over winter? That'll matter as much as consumption — short days up north basically means the batteries are doing all the heavy lifting til spring.

@PartnerCamper winter on the cut is a different beast entirely. My setup pulls around 120–150Ah daily once you factor in the inverter running an induction hob, LED lighting, and the 12V pump. That's with a 400W solar array doing almost nothing from November through January — basically decoration at that point.

The SmartShunt data will probably shock you initially. Mine revealed I was consistently draining further than I thought overnight. Worth setting up the Victron Connect history graphs so you can spot patterns across a week rather than just single days.

Two 100Ah Fogstar Drifts at 200Ah usable is a fairly modest bank for liveaboard winter use — are you running an alternator or a Sterling B2B for engine charging? That'll matter a lot more than solar once the days get short.

@PartnerCamper interesting timing — I've just been comparing winter consumption figures across my narrowboat and a shepherd's hut build, and the boat consistently surprises me.

With a similar 200Ah LiFePO4 bank (Fogstar cells, Victron SmartShunt 500A), my daily winter draw sits around 140–170Ah once the diesel heater's fan, LED nav lights, and a fairly modest 12V fridge are factored in. The killer nobody mentions is inverter standby draw — even a Victron Multiplus on eco mode nibbles constantly.

One thing worth checking in your VictronConnect data: Peukert exponent settings. The default values are calibrated for AGM; LiFePO4 wants something closer to 1.05, otherwise your State of Charge readings drift badly in colder temperatures.

What's your charging source — are you relying purely on the alternator or have you got solar on the roof too?

@PartnerCamper brilliant timing getting that SmartShunt wired before the cold really bites. I've got one on my Duchessa (70ft trad stern, imaginatively named "The Floating Mistake") and winter absolutely humiliates whatever estimates you made in August.

My worst offenders:

• Diesel boiler pump — surprisingly thirsty little gremlin
• LED nav lights running longer dark hours
• Inverter vampire draw just sitting there breathing

I typically land around 130–160Ah daily once we're properly into December. The Fogstar Drifts are decent but watch your low-temperature charging cutoff — had one very educational morning at Braunston discovering LiFePO4 does not enjoy being charged at 2°C. Victron's low-temp sensor saved me from an expensive mistake the second time around.

@BoatMel's 120–150Ah figure tracks with my experience too. Factor in a diesel stove blower and you'll creep toward the higher end fast.