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

Winter driving is genuinely brutal for keeping batteries topped up — short runs are almost pointless depending on your setup.

The core problem is that most factory split-charge relays only kick in once the alternator is properly loaded and voltage climbs above a threshold. On a 20-minute school run equivalent pootle, you're barely getting anything meaningful into the bank before you switch off again.

Switched to a Victron Orion-Tr Smart DC-DC charger last autumn and it's transformed things. Properly charges at a set current regardless of alternator voltage fluctuations, and the Bluetooth monitoring is genuinely satisfying to watch on cold mornings. Not cheap, but worth every penny given how much I was stressing about my Fogstar Drift lithium not getting enough love through the darker months.

A few things that made a difference for me:

• DC-DC charger rather than relying on a basic relay
• Keeping solar topped up where possible (yeah I know, UK winters... 😅)
• Setting a lower state-of-charge threshold so the battery isn't fighting uphill from 40%

The solar point is a bit of a joke right now admittedly — my 200W panel has been largely decorative since October.

Anyone running a DC-DC already? Curious whether others are pairing it with lithium or still on AGM. Also wondering if anyone's tried the Renogy equivalent — seems decent on paper for the price difference but I've not tested one myself.

Would love to know what others are doing to manage this through the winter months rather than just plugging into hook-up every time you get a chance.

@MoorLee — this was exactly my situation last winter touring Scotland. Factory relay was basically decorative on anything under an hour's drive.

Swapped it out for a Victron Orion-Tr Smart DC-DC charger and it transformed things completely. The clever bit is it actually charges rather than just connects — so even a 20-minute run to the village shop was genuinely putting something useful back into my Fogstar lithium.

Worth noting the Orion also handles the voltage difference properly if you've got a modern Euro 6 engine with smart alternator — those variable-voltage alternators will confuse a basic relay something rotten and potentially damage your battery in the process.

It's not the cheapest fix, but compared to a knackered battery mid-January on a Scottish hillside, the maths works out fine.

A DC-DC charger sorted this for me — Victron Orion 30A. Even on a 20-minute run it's actually pushing meaningful current into the leisure bank rather than whatever dribble the old split-charge relay managed to produce.

Worth noting the alternator temperature issue too. Modern Euro 6 engines with smart alternators can drop voltage unpredictably, which confuses relay-based systems completely. The Orion handles that properly.

One thing people overlook: check your cable run from the starter battery. I found 6mm² cable on a previous van was strangling the whole setup before I'd even considered the relay itself. Upgraded to 10mm² and saw an immediate difference.

Solar is effectively useless December through February if you're parked north of Birmingham anyway, so don't let anyone convince you a small panel solves a winter charging problem.

@BodgeItAndScarper is right about the Orion, though I'd add — don't cheap out on the cable run to it. I lost nearly 4A of charging potential before I even got started because the previous owner had used undersized wire.

Also worth checking your alternator output in cold weather. Mine (a 90A unit) was barely producing 60A at idle in January — the DC-DC charger is only as good as what it's pulling from.

If you're doing mostly short runs, honestly consider a small solar panel on the roof as a supplement. Even a 100W Renogy panel on a gloomy winter day trickles something in, which stacks with whatever the alternator manages.

The factory relay situation is a lost cause — bin it or bypass it properly.

Great points all round. One thing worth adding — if you're doing lots of short winter runs, it's worth setting the DC-DC charger's absorption voltage correctly for your battery chemistry. I had mine defaulting to AGM settings when I'd fitted lithium, and it was cutting out way earlier than it should. Also consider pairing it with a solar panel if you haven't already — even a modest 100W panel in winter gives you something while parked up, so the alternator doesn't have to do all the heavy lifting on those brief drives. The two together make a proper difference. @BodgeItAndScarper the Orion really is the sweet spot for the money isn't it — I've had mine three years now without a hiccup.

Swapped to a Fogstar lithium last year and suddenly my DC-DC charger actually has something worth charging into — lead acid in winter was basically a black hole for electrons.