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

Short drives in winter are genuinely brutal on battery management — you're fighting a losing battle between alternator charge time, high parasitic loads, and a BMS that won't accept charge properly when the cells are cold.

On my van conversion I run a Fogstar Drift 100Ah LiFePO4 and learned fairly quickly that a standard B2B charger setup will barely tickle it on a 20-minute school run. The alternator simply doesn't have enough time to push meaningful current before you've parked up again.

A few things that helped me:

• Upgraded to a Victron Orion-Tr Smart 30A DC-DC charger — the difference over a basic relay split charge is significant, and you can monitor exactly what's going in via the app
• Solar as a baseline — even a 100W panel on a grey January day in the Midlands will contribute something overnight and morning. Not much, but it reduces how much the alternator needs to compensate
• Pre-heating the battery — LiFePO4 won't accept charge below around 5°C on most BMS configurations. Worth checking your cutoff settings if you're parking somewhere cold overnight

The honest answer though is that short winter drives will never adequately charge a decent leisure bank through the alternator alone. You really need shore power or solar as your primary source, with the alternator as a supplement.

What's everyone else running for DC-DC charging? Curious whether anyone's pushed beyond 30A without alternator issues on a modern Euro 6 van — I've heard mixed things about smart alternators playing nicely with higher draw B2Bs.

@WayneJames been there with my shepherd's hut setup (different beast, I know) but the fix that saved my sanity was a Victron Orion-Tr Smart DC-DC charger — it tricks the BMS into accepting charge properly and you're not just chucking unregulated alternator voltage at your lithiums like a caveman. 🐑🔋

Not directly motorhome experience but running a garden office on a similar split-charge arrangement taught me the same painful lessons.

The core problem on short winter runs is the alternator barely gets the LiFePO4 above resting voltage before you've parked up again. A DC-DC charger (B2B) rather than a basic VSR makes a significant difference — the Victron Orion-Tr Smart 30A is the one I'd spec every time. It'll pull a proper controlled charge profile even from a half-warm alternator.

Also worth checking your BMS low-temperature cutoff threshold. Many budget cells — Fogstar included — will reject charge below around 5°C, which in a poorly insulated bay in January means you're effectively charging nothing despite the dashboard suggesting otherwise.

Combining a B2B with a small solar input, even 100W, gives you at least a trickle between drives to keep the BMS happy.

Not a motorhome but my static caravan setup taught me loads about exactly this. Short winter drives won't cut it — the alternator barely gets going before you're parked up again.

Worth looking at a DC-DC charger (B2B) rather than relying on a basic split-charge relay. Makes a massive difference — properly conditions the charge for lithium. Victron Orion-Tr Smart is what I've got and it's transformed things.

Also worth checking your parasitic drain — winter heating controllers and alarm systems can quietly murder a battery overnight without you realising. Grabbed a basic clamp meter and was genuinely shocked what mine was pulling.

If short drives are your main use pattern, honestly just supplement with a small solar panel. Even 100W does something useful on a bright winter day.

Been grappling with exactly this trying to keep my shepherd's hut battery happy during the bleaker months, and the pattern I noticed is that the alternator spend so much energy just warming a cold lithium pack that you've barely moved the needle by the time you've arrived.

What turned things around for me was adding a small DC-DC charger (Victron Orion-Tr Smart) rather than relying on a direct split-charge relay. The relay approach is hopelessly dumb in winter — the Orion actually manages the profile properly regardless of temperature.

Also worth considering: if you're doing short hops regularly, just accept the alternator isn't your primary source and lean on shore power or a small solar top-up overnight. Trying to force the alternator to do all the work on a 20-minute school run is a losing game.