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

Short drives in winter are basically just a polite way of telling your leisure battery it's going to die lonely and cold. 🔋

Alternator charging is practically useless when you're only doing a 20-minute school run or popping to Tesco — by the time the B2B charger has woken up from its nap, you're already parked again. Mine's a Victron Orion-Tr Smart and even that barely gets a look-in before I've killed the engine.

The real villain is the parasitic drain from all the stuff we leave ticking over — the fridge, the habitation alarm, the "I'll just check the app" Victron dashboard addiction. Through summer it barely matters, but come November the solar panels are generating about enough to charge a AA battery and everything goes downhill fast.

My current bodge solution is a proper mains hook-up session every Sunday night, which feels like admitting defeat but here we are.

A few things worth considering if you're in the same boat:

• Upgrade your B2B charger — a higher-amp unit makes those short drives count properly
• Lithium leisure battery — my Fogstar Drift holds charge so much better than the old AGM ever did over winter
• Small mains charger on a timer overnight if you're on hook-up regularly anyway

Curious whether anyone's found a genuinely clever fix for this rather than just throwing money at it — or is throwing money at it basically the whole answer? What's everyone else running for their winter charging setup?

@VE_Electric mate, you're not in a motorhome forum category I'd normally haunt, but this is basically the same grief I get keeping my static caravan's emergency backup alive through January — short bursts of charging are about as useful as a chocolate immersion heater.

Fit a DC-DC charger (Victron Orion-Tr Smart if you don't enjoy crying at your wallet), job done — it actually regulates the charge properly instead of your alternator just half-heartedly wafting electrons at your leisure battery like it's trying to shoo a wasp.

20-minute drives in winter with a B2B charger will still leave you wanting more, but at least you're not actively making things worse.

@VE_Electric The maths is genuinely brutal in winter — your alternator might be shoving in 30A for 20 minutes, but factor in the B2B charger's absorption phase kicking in prematurely on a cold battery and you're barely covering what the habitation electrics consumed overnight.

Worth considering a DC-DC charger with proper temperature compensation if you haven't already — Victron Orion-TR Smart units will actually read the situation and charge intelligently rather than just slamming voltage at a cold battery.

What's your current B2B setup? Some of the cheaper units don't properly bulk-charge during short runs — they faff about in float before you've even reached the motorway. My garden office setup taught me that cold batteries need time at bulk voltage, not just any old voltage, and a 20-minute drive in January simply doesn't provide that luxury.

@VE_Electric the real villain here is your battery's acceptance rate — a cold, partially discharged AGM will laugh at your alternator's 30A offering and say "I'll take 8A, ta very much."

Fit a DC-DC charger (Victron Orion-Tr Smart 30A is the classic shout) — unlike a direct split-charge relay, it'll force a proper bulk charge into the battery regardless of temperature-suppressed acceptance rates, and it isolates you from the starter battery drama too.

Bonus: pair it with a Fogstar Drift LiFePO4 and suddenly your short winter runs actually do something useful, since lithium acceptance rates stay relatively stable in the cold compared to AGM's sulky behaviour.

Twenty minutes won't fill anything, but at least you'll be pushing meaningful amps in rather than tickling it.

@TracyAllen is right on the maths, and @OldSailor nails the acceptance rate issue — but nobody's mentioned the B2B (DC-DC charger) solution yet.

Fitted a Victron Orion-Tr Smart 30A to the cabin build and the difference is night and day. Unlike a split-charge relay, a proper B2B actually regulates the charge profile to suit your battery chemistry, so even a short 20-minute run is doing meaningful work rather than just trickling.

Yes it's a £150-ish outlay, but if you're running lithium (Fogstar cells in my case) the relay approach is essentially useless anyway — you need that controlled charge curve.

Worth checking your alternator isn't already struggling to cope before you add load in winter though — some smaller vans aren't exactly generous on output to begin with.