Anyone else struggling to keep leisure batteries topped up on short winter trips?

Same issue here last couple of winters with my motorhome. Short hops of 2-3 hours just weren't cutting it for keeping my 200Ah lithium bank (Fogstar Drift cells) properly topped up, especially with the short daylight hours killing solar output too.

Few things that helped me:

• Shore power hookup whenever possible — even just overnight at a services with EHU sorted it
• Upgraded the B2B charger — went from a cheap unit to a Victron Orion 30A and the difference in charging efficiency on the move is noticeable
• Reduced loads — switched to LED lighting throughout and got a bit more disciplined about the diesel heater runtime

The real game changer was actually accepting that winter tripping just needs more planning around power. I started looking at CL sites with hookup rather than wildcamping, at least for the shorter trips.

What's your setup — AGM or lithium? AGM is much harder to keep happy in winter because you really need to get them to 100% regularly or you're shortening their life. Lithium is more forgiving if you're sitting at 70-80%.

Also worth checking your alternator charging — a lot of older motorhomes have a poorly rated cable run to the leisure bank and you're losing loads to resistance.

Anyone found a decent solution for genuinely off-grid winter trips without EHU? Curious whether a small genny is worth the hassle or if I should just look at more solar panels despite the low sun angle.

@Davo83 nothing like paying premium lithium prices to find out your alternator charges it with the enthusiasm of a retired tortoise 🐢

@Renogy_Nerd 😂 brutal but fair

Had exactly this with my garden office setup before I sorted the solar side. For the van though — have you looked at a DC-DC charger? Victron Orion-Tr Smart is the go-to. Your alternator puts out a proper charge profile rather than just dribbling whatever voltage it fancies.

Short hops genuinely won't cut it without one, lithium or not. The Orion basically tricks your alternator into working properly for your bank.

Couple of roof panels if you can fit them wouldn't hurt either — even winter sun does something useful when you're parked up. Not a magic fix but every bit counts when days are short.

@Davo83 the root issue is that your alternator's voltage profile simply doesn't suit lithium chemistry properly — most factory setups are tuned for AGM and will throttle back before your Fogstar cells are meaningfully full.

Worth looking at a DC-DC charger (B2B) rather than relying on direct alternator feed. Victron Orion-Tr Smart 30A is the go-to — it actively steps the voltage up correctly and keeps a consistent charge current throughout the drive, so even a 90-minute motorway run delivers something useful.

Pair that with even 200W of roof solar and a decent MPPT (Victron 75/15 handles that fine) and winter top-ups become far more manageable. My static caravan setup runs a similar hybrid approach and the difference in winter SoC is night and day compared to solar alone.

The B2B is genuinely the single biggest upgrade for short-trip charging.

@VanGill is right about the voltage mismatch but there's a practical fix rather than just moaning about it — DC-DC charger (B2B). Victron Orion-Tr Smart 30A sorted mine completely. Pulls a proper charge profile from the alternator regardless of what the alternator "thinks" it's doing.

On a 2-3 hour run you're realistically getting maybe 15-20Ah into a 200Ah bank without one, absolute joke. With the Orion I'm seeing proper bulk/absorption cycles actually completing.

Worth noting — if you've got a smart alternator (most post-2015 vehicles do) a B2B isn't optional, it's basically mandatory. The voltage fluctuates all over the place otherwise and your BMS will throw a fit.

Fogstar cells deserve better than a bare alternator connection tbh, they're decent cells.

@WezFrost is on the right track with DC-DC — been running a Victron Orion-Tr Smart 30A in the narrowboat for two seasons now and the difference is significant. What's worth adding is the isolation side of things: the Orion keeps your lithium bank genuinely separate from the starter battery, so you're not risking a flat crank battery if the BMS decides to disconnect under load.

For @Davo83's short-hop scenario specifically — even 30A input over a 2-hour run at, say, 13.8V input is roughly 55-60Ah recovered, which is meaningful if you're disciplined about what you're running overnight.

One caveat: check your alternator's duty cycle before throwing a constant 30A load at it in winter. Older or smaller alternators can run hot when they're also powering heating blowers, lights, and nav systems simultaneously.