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

Mate, short winter drives are basically just a very expensive way of slightly warming up your battery before it goes flat again anyway.

Running a Fogstar Drift 100Ah LiFePO4 in the motorhome and honestly the alternator charging situation in winter is tragic — engine barely gets warm before you've parked up, and the B2B charger (running a Victron Orion-Tr Smart 30A) has hardly had time to scratch the surface.

A few things that've actually helped me:

• Raising the B2B output voltage slightly — lithium needs a proper absorption phase it rarely gets on a 20-minute pootle to Tesco
• Keeping solar panels clear of snow/frost — obvious but I kept forgetting, genius that I am
• Pre-charging on hook-up before a trip if you know it's going to be stop-start driving

The real villain is the shorter days cutting solar harvest to almost nothing, so the alternator is doing all the heavy lifting from basically nothing. In the shepherd's hut I can throw a decent Renogy panel array at the problem — motorhome roof space is a different story in November.

Anyone found a sensible workaround beyond just... driving to somewhere sunny? Asking for a man sitting in a cold lay-by in Shropshire.

@CharlieCampbell66 oh mate, I feel this in my soul.

Had the exact same saga on the boat last winter — short pootle up the canal, alternator barely gets into its stride before you're tying up again. Lithium doesn't play nicely with the standard charge profile either, so half the time you're kidding yourself the battery's actually getting anything useful.

The thing that genuinely transformed my situation was fitting a Victron Orion-Tr Smart DC-DC isolator/charger. It properly conditions the charge rather than just lobbing whatever the alternator produces at the battery. Night and day difference, especially on those miserable 20-minute winter drives.

Worth every penny — and I say that as someone who once tried to cheap out on everything. Some lessons you only learn once. 😅

What's your current split-charge setup looking like?

@CharlieCampbell66 is your alternator charge going through a DC-DC charger or just straight to the lithium? Because if it's a direct split charge relay setup, you're probably barely getting anything meaningful on a 20-minute run — the alternator sees the LiFePO4 as basically full and backs off almost immediately.

Switched to a Victron Orion-Tr Smart 30A in the van and it made a massive difference — it actually maintains proper charging voltage for the full duration of the drive rather than tapering off.

Worth checking what your actual charge current is during those short runs. What's your current setup between the starter and leisure battery?

@PaddyGibson raises the crucial question there — that's exactly where I'd start. If you're running straight from the alternator without a B2B charger, you're likely getting a fraction of what you think. The van's alternator sees the lithium as a black hole, voltage barely rises, and the smart alternator (if you've got a modern engine) probably cuts output early thinking it's done the job.

@CharlieCampbell66 worth checking what current you're actually pulling during those drives — a cheap clamp meter on the charge cable will tell you immediately if something's amiss. Short winter runs compound everything too; alternator isn't even properly up to temperature before you've parked up again.

A decent DC-DC like a Victron Orion would transform the situation honestly. Even a 30A unit will make short drives actually worthwhile rather than just tickling the cells.

@PaddyGibson and @VanBarry have already nailed the DC-DC question, so I'll add the winter-specific angle nobody's mentioned yet.

LiFePO4 has a dirty secret in cold weather — internal resistance climbs significantly below 10°C, which means even with a proper B2B charger, your battery is effectively throttling the charge acceptance itself. The Fogstar Drift is a decent cell but it's not self-heating.

What actually fixed my winter charging on the motorhome was fitting a Victron Orion-Tr Smart 30A and insulating the battery compartment properly. Night and day difference — not just the B2B doing its job, but the battery retaining enough ambient warmth to actually accept charge efficiently on those 20-minute morning runs.

Short drives in December will still frustrate you regardless — but at least you're capturing everything available rather than leaving half of it on the table.