Winter vanlife — keeping warm without killing batteries

The diesel heater's brilliant for bulk heat, but honestly the real win is layering everything. I've got thermal blinds on all the windows—proper game-changer for retention—and I draughtproofed the living daylights out of the van last autumn. Makes a measurable difference to how often the heater actually cycles.

One thing that's saved me: I'm running my Webasto on a timer rather than constantly. Heat the van properly in the evening, let it coast through the night with good insulation doing the heavy lifting. Battery drain is way less aggressive than I expected.

Also worth considering your solar situation for winter. Even on grey UK days, I'm getting 100-150W regularly on my Fogstar 200W panel when mounted at a decent angle. Not going to run the heater, but it chips away at the parasitic draw and takes pressure off overnight discharge.

@BevJackson64 and @Louise1984 are spot on—it's the whole system, not just the heater. What's your insulation like?

The diesel heater sorted my setup years ago, but here's what nobody mentions — it's the parasitic draws that'll kill you silently. I've got a narrowboat that doubles as emergency backup accommodation, and I learned this the hard way.

Your heater runs on diesel, brilliant. But what's running on your batteries while it's heating? Pump, fan controller, maybe a 12V circulation system if you're doing proper hot water distribution. That's 20-30A easy, and it adds up across a winter night.

What actually changed things for me was realising the heater buys you time, not a free pass on battery management. @Louise1984's onto it — you still need serious capacity. But even then, I invested in a small LiFePO4 pack (200Ah Fogstar) dedicated entirely to the heater circuit, charged separately during the day. Sounds mad, but it decouples the heating drain from your main house bank.

The layering @LizStewart mentions is the unglamorous bit that actually works though. Thermal blinds, draft sealing, decent insulation. Get your van

Mate, @VictronPro's spot on about the parasitic draws — I learned that the hard way. Had my static caravan absolutely hemorrhaging power last winter from a dodgy fridge controller running 24/7. Killed the whole battery setup by January.

Diesel heater's definitely the move though. Mine's a cheapy Fogstar knock

Yeah parasitic draws are mental — had a £40 USB charger left plugged in on my old setup and it was pulling 80mA constant. Didn't realise for months.

What's actually changed my winter game though is proper battery monitoring. Got a Victron BMV-712 installed and now I can see exactly what's draining what. Turns out my fridge was the culprit more than the heating — old compressor was working overtime in the cold.

Combo that sorted it:

• Swapped the fridge, killed that drain
• Diesel heater for baseline (Fogstar unit in mine, does the job)
• Heavy thermal blinds as @LizStewart says
• Turned off everything non-essential at night

The real thing is you can't just throw more batteries at it — you've got to find where the power's actually going. Once you do, winter becomes manageable without your battery bank flatening every 3 days.

Static caravans are easier honestly, at least you can run a proper mains hookup most sites.

The parasitic draw angle is absolutely crucial, but there's another dimension worth exploring here — when you're actually heating.

I've got a static caravan setup running a Victron SmartShunt to monitor every milliamp, and what surprised me was the difference between thermostat-controlled heating versus manual cycling. A Webasto or Espar running continuously to maintain 15°C burns far less battery than people assume, but the real killer is the auxiliary draws feeding it — fuel pump, glow plug cycles, the control module itself pulling power even when dormant.

What I've found critical:

• Isolate the heater on its own circuit with a dedicated battery monitor. You'll see exactly what it costs nightly
• Two-stage approach: run the heater on a timer for early morning/evening, then drop to passive insulation overnight. My consumption halved doing this
• Check your fuel consumption figures — a Webasto pulling 0.5L/hour actually costs less battery than you'd think if you're running a 200Ah bank with decent solar recovery

The real win for winter isn't necessarily *

Diesel heater's essential, agreed—I've got a Webasto too. But @ZFS_OffGrid's spot on about parasitic draws; they're sneaky killers in winter when battery capacity's already shot. Worth auditing everything: fridge, chargers, alarm systems. I found my leisure battery was dropping 5% overnight just from phantom loads. Kill the non-essentials when stationary.

Got a diesel heater sorted in mine too, but honestly the game-changer was killing all the standby draws first. Phantom loads add up fast — had a fridge parasitic that was costing me hours of battery daily. Once you've plugged those holes, the heating becomes way more manageable. Worth an audit before splashing out on a bigger battery bank.

Third winter in my van and I learned this the hard way — a diesel heater's brilliant, but it's worthless if your leisure battery's hemorrhaging juice to fridge compressors and control modules on standby. I've got a Victron battery monitor now and it showed me I was losing 3-4% overnight just sitting there. Sorted the parasitic draws first, then added the heater. Made all the difference.

Has anyone actually measured the efficiency difference between a Webasto and something like a Planar? I'm looking at a shepherds hut setup and wondering if the cheaper Chinese alternatives hold up through a proper UK winter, or if you're throwing money at a problem that needs the proper kit. What's the real-world cost difference over a season?