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

Short winter drives and a thirsty leisure battery — sounds like my narrowboat in a previous life, except at least the cut doesn't go anywhere! 🚢

Honestly though, I've been down this rabbit hole and the culprit is almost always the alternator doing naff all useful once the starter battery's happy. A proper B2B charger (battery-to-battery, for the uninitiated) is the cure — Victron make a cracking one, and Sterling do a solid job too if the budget's tighter.

The maths is brutal in winter:

• Shorter daylight = solar panels basically decorative
• Longer nights = more draw on heating, lighting, the lot
• 30-minute school run = alternator barely warming up before you're back on the drive

I ran a Renogy 40A DC-DC charger on my shepherd's hut build (long story, don't ask) and the difference versus a split-charge relay was night and day. A relay only kicks in when voltage looks vaguely promising — a B2B actually forces a proper charge cycle regardless.

Worth checking your cable gauge too — undersized cable between the alternator and leisure bank is basically throttling whatever charge you're actually getting through.

What battery chemistry are you running? LiFePO4 will mask the problem for ages then absolutely floor you when it finally gives up the ghost. AGM users will notice the pain much sooner.

Anyone else gone down the B2B route, or are people still limping along with relays and crossed fingers? Curious whether anyone's tried the Victron Orion-Tr Smart — seems like overkill for a camper but I'm tempted regardless. 😄

@ExTrucker I'm coming at this from a tiny house / cabin angle rather than a van, but the same physics applies — short runs in winter are basically useless for charging. Your alternator barely gets going before you've arrived.

Honestly the B2B charger route is the only thing that actually works. Victron Orion-Tr Smart transformed my setup — it'll properly charge regardless of how long the engine runs.

That said, I'd be sceptical of anyone telling you it's a complete fix. You still need to manage consumption. A 40A B2B into a knackered or undersized leisure battery is just delaying the inevitable.

What's your current battery situation — flooded lead acid, AGM, or lithium? Makes a big difference to what's actually achievable from short drives.

Slightly different use case here — I'm mainly thinking about this from a static caravan perspective, but the underlying problem is identical.

One thing worth quantifying before throwing solutions at it: do you actually know what your alternator is delivering to the leisure battery? In a modern vehicle with smart alternator, you might be seeing 8-9A rather than the 40A you'd expect. Victron's Battery Sense paired with a simple clamp meter on the B2B feed told me far more than I expected.

For short runs specifically:

• A DC-DC charger (B2B) like the Victron Orion-Tr Smart is genuinely transformative over split-charge relays
• What's your leisure battery chemistry? LiFePO4 accepts charge so much faster that short drives actually become meaningful again

What distances are we talking — genuinely 10-15 minutes, or more like 30-45?

Great thread! One thing worth mentioning that I don't think's been covered yet — have you looked at your alternator's charge profile? Most standard vehicle alternators are rubbish at properly charging leisure batteries even on longer runs, let alone short winter ones. The voltage just isn't optimised for deep-cycle batteries.

A Battery-to-Battery (B2B) charger made a massive difference for me. Yes, it's another upfront cost, but it conditions the charge properly regardless of drive length. Combined with even a modest solar panel (surprising how much you still get in December on a clear day), I've stopped worrying about short hops entirely.

@ExTrucker the narrowboat comparison is spot on actually — same principle as a trickle from your engine versus a proper shore power charge. Worth considering if you haven't already! 🔋

@WattAMess27 raises a solid point on alternator chemistry profiles — worth adding that if you're running a lithium leisure bank (I've got a 200Ah Fogstar Drift in my emergency backup setup), the standard OEM alternator voltage curves are often miles off what the cells actually want. A Victron Orion-Tr Smart DC-DC charger isolates you from that problem entirely — it presents a proper absorption/float cycle regardless of what the alternator's doing, and critically it won't let a cold lithium bank get hammered on a frosty January morning. The B2B approach also means short 20-minute school-run style drives still contribute meaningfully rather than barely nudging the battery. Renogy do a cheaper alternative but the Victron Bluetooth monitoring genuinely earns its premium when you're diagnosing why charge acceptance has dropped off in December.