Anyone else struggling to keep the leisure battery topped up on short winter drives?

Narrowboat life taught me this lesson the hard way — short runs are basically useless for charging anything meaningful, especially when the alternator's spending half its time just warming up its own ego.

Swapped over to a DC-DC charger (Victron Orion-Tr Smart, naturally) and it genuinely transformed things. Instead of your battery getting whatever scraps the alternator feels like chucking at it, you get a proper controlled charge — even on a 20-minute pootle to Lidl and back. The difference in winter especially is night and day because it's not fighting voltage drop and temperature at the same time.

The other option folks don't talk about enough is just accepting defeat gracefully — chuck a small solar panel on the roof (even 100W Renogy job does something in December, bless it) and let it trickle away while you're parked up staring at a grey sky wondering why you own a motorhome.

If you're still on a bog-standard lead-acid leisure battery, that's your other problem right there. Lithium from Fogstar holds charge so much better over winter — no weird voltage sag making your charger think it's already full when it absolutely isn't.

Genuinely curious — what split charge relay setup are people running? Still seeing folks on ancient VSR systems wondering why nothing works. 😅

@Stu1991 my Fogstar 206Ah lithium just sits there laughing at my 20-minute school run like it's been personally insulted — DC-DC charger was the only thing that saved my sanity, alternator goes straight into it properly regulated rather than doing its half-hearted "I'll try my best" impression all winter.

@LazyRanger a B2B charger sorted my narrowboat misery — DC-DC from Victron means even a 15-minute chug actually does something useful instead of just tickling the battery's feelings.

@EssexNomad is absolutely right about the B2B route, and I'll add some nuance from running a 40A Orion-Tr Smart on my boat for two winters now.

The key thing people miss is the absorption phase — your lithium doesn't care about being bulk-charged quickly if it never reaches the tail current threshold. With a properly configured Orion, even a 12-minute engine run pushes a controlled 40A the whole time rather than the alternator's chaotic taper-off behaviour.

Worth checking your engine alternator rating too — @LazyRanger if you're pulling 40A from a 70A alternator in January with heated screen, blower, and headlights running, your alternator's struggling before it's even looked at that Fogstar. B2B chargers respect that load balance properly.

Also worth enabling the Victron's input voltage lock-out so the alternator isn't hammered cold from a standing start.

@ForestBoater same Orion-Tr Smart on the narrowboat here — though I mostly learned its value when the solar panels decided February didn't exist.

@ExFarmer that solar dependency issue is exactly why I treat the B2B as part of a layered system rather than a standalone fix. On my boat I pair the Orion-Tr Smart with a Fogstar Drift LiFePO4 bank — the tight acceptance curve of lithium means every amp the B2B pushes actually lands efficiently, whereas flooded lead acid was soaking up maybe 60% of what I thought I was putting in.

Worth noting for anyone running emergency backup alongside their leisure bank: the B2B's isolation function is genuinely useful when you need to guarantee starter battery integrity regardless of leisure bank state. Learned that after a particularly grim January morning on the cut. Profile the Orion correctly for your chemistry and the short-run problem largely disappears — 20 minutes becomes meaningfully productive rather than theatre.