VANILLA // AUTUMN ARMOUR 🍂🔥🔋🚐

How My Webasto and Fogstar Are About to Transform My Little Metal Hovel

Summer lets campervan owners get away with murder. You can leave a vent cracked, chuck a blanket over yourself, ignore the heater, ignore the battery, ignore the damp and generally pretend your little metal box is some sort of boutique hotel on wheels.

Then autumn arrives.

And the van starts telling you the truth.

The mornings are colder. The glass gets wetter. The air feels heavier. The temperature drops faster after sunset. Everything that felt effortless in July suddenly becomes something you have to manage.

That is exactly what my data has shown.

Over the last few months Vanilla has quietly recorded nearly 100,000 interior climate readings, minute by minute, while I have been travelling, camping, tinkering and generally living far too enthusiastically inside a Volkswagen Transporter.

Temperature. Humidity. Dew point. Absolute moisture. Outside conditions. The lot.

And the pattern could not be clearer.

Summer was easy.

Autumn is where Vanilla starts earning its keep.

And this year, two things are about to change the game completely:

My Webasto diesel heater.

And my new Fogstar 105Ah LiFePO4 leisure battery.

Together they should turn my little metal hovel into something far more important than merely warm.

They should make it properly comfortable.

Properly dependable.

Properly autumn-proof.

July was gloriously simple.

The average overnight temperature inside Vanilla sat around 24°C, while humidity generally hovered in the low 50s.

In other words, the weather was doing most of the work for me.

The van soaked up heat during the day, held onto it surprisingly well into the evening and rarely got anywhere near serious condensation conditions.

There were moments when Vanilla actually held too much heat.

At one point the sensor briefly saw around 47.5°C after a day of solar loading.

Forty-seven degrees.

Inside a Volkswagen.

That is not campervan comfort.

That is focaccia proving temperature.

But it taught me something useful very early on: campervan comfort is not about chasing the highest possible temperature.

Sometimes the challenge is getting rid of heat.

Raise the pop-top.

Open the side door.

Crack the windows.

Get some airflow moving.

A campervan is basically a giant insulated biscuit tin with glass in it.

Sometimes that is brilliant.

Sometimes it becomes an oven with alloy wheels.

By bedtime, though, July was usually easy.

Warm air. Low-ish humidity. Plenty of distance from the dew point. Dry bedding. No drama.

Summer was Vanilla in easy mode.

By August, average overnight temperatures had dropped to roughly 21°C.

Still lovely.

But humidity began creeping upward.

And this is where one of the most important campervan lessons started showing up in the data:

Warm does not necessarily mean dry.

A van can be cosy and still be holding a surprising amount of moisture.

Cooking adds it. Wet coats add it. Boiling water adds it. Shoes add it. Breathing adds it.

And because a Transporter is a tiny living space compared with a house, those changes happen quickly.

You are effectively sleeping in a very expensive metal shoebox.

A brilliant shoebox, obviously.

But still a shoebox.

And overnight, one sleeping human can change the atmosphere inside far more than I expected.

Anyone who has slept in a campervan through autumn knows the morning ritual.

Wake up.

Look at the windows.

Assess the carnage.

A little misting? Fine.

A couple of wet corners? Manageable.

Windscreen resembling the inside of a greenhouse? Something has gone wrong.

This video is a good practical companion to what my sensors are showing, with real-world UK campervan condensation and ventilation advice. YouTube

Before I started all this, I would probably have looked at temperature and relative humidity.

Now I care about something else almost as much:

Dew point.

It sounds technical.

It really isn’t.

Dew point simply tells me how cold a surface has to become before water starts condensing on it.

Imagine Vanilla is 18°C inside with a dew point of 12°C.

That gives me 6°C of margin.

Pretty decent.

Now imagine the cabin is 15°C with a dew point of 13.5°C.

That gives me just 1.5°C of margin.

Suddenly the windscreen, metal pillars, window edges and door frames are all candidates for condensation because those surfaces can easily be colder than the general cabin air.

That is why a campervan can feel warm enough and still wake up wet.

It is also why I now mentally run a little Vanilla traffic-light system.

🟢 More than 5°C between air temperature and dew point: lovely.

🟠 3–5°C: keep an eye on airflow and cold surfaces.

🔴 3°C or less: condensation territory.

💦 Close to zero: congratulations, the windows are probably joining in.

September is where Vanilla stopped being a summer toy and started becoming a proper four-season experiment.

Average overnight temperature fell to around 19.5°C.

Average relative humidity rose to around 63%.

Still perfectly usable.

Still comfortable on plenty of nights.

But now the cold and moisture were starting to cooperate against me.

And one morning in particular showed exactly what autumn can do to a small campervan.

At around 07:54, Vanilla recorded:

15.5°C

90% relative humidity

13.9°C dew point

That left just 1.6°C between the air temperature and saturation.

That is tiny.

It means that any glass, pillar, metal edge or trim surface just slightly colder than the cabin air could start collecting water.

And campervans are absolutely full of those cold bridges.

Windscreen. Cab glass. Door frames. Metal ribs. Pop-top frame. Window edges.

All those places where a warm little interior meets a cold autumn world.

That was the moment the experiment really clicked for me.

The enemy is not simply cold.

The enemy is cold plus moisture.

A 15°C van with dry air can be perfectly tolerable.

A 15°C van with 90% RH feels like somebody has wrapped the bedding in a damp tea towel.

And that is where the Webasto changes everything.

I used to think of the Webasto in the obvious way.

Cold outside?

Turn heater on.

Warm van.

Job done.

But after watching the data, I now think of it differently.

The Webasto is not simply a heat source.

It is part of Vanilla’s climate-control system.

When it is working properly, it changes the relationship between the cabin and the outside world completely.

One of my latest overnight datasets was almost absurdly good.

Outside average temperature:

14.8°C

Inside average temperature:

23.1°C

That means Vanilla maintained an average thermal advantage of about:

8.3°C

Inside humidity:

54%

Outside humidity:

73%

Minimum interior temperature:

21.7°C

Minimum dew-point margin:

8.9°C

That is a completely different environment from the damp September morning.

Same van. Same body. Same glass. Same British weather.

Completely different result.

Outside, autumn.

Inside, T-shirt weather.

That is what a proper diesel heater does to a campervan.

Without heat, the van is shelter.

With controlled heat, it becomes a room.

RAIN OUTSIDE. TOAST INSIDE.

This is the version of campervan life I love.

Rain tapping on the roof.

Cold ground.

Wet grass.

Mist.

That sort of morning where people are standing outside their vans wearing three coats trying to make coffee before their hands stop working.

Meanwhile inside Vanilla:

Warm bedding.

Soft lights.

Fridge humming.

Coffee going on.

Phone charging.

Webasto ticking gently away.

Maybe the projector still sitting there after the night before.

Maybe the Sonos humming quietly.

And the outside world looking thoroughly inconvenient through the glass.

That is campervan luxury to me.

Not marble worktops.

Not sixteen cupboards.

Not a television on an electric lift.

Just being warm and dry somewhere beautiful when the weather outside has absolutely no interest in cooperating.

This was one of my favourite discoveries.

On that lovely warm October night, the inside relative humidity was much lower than outside.

You would assume that meant the air inside was drier.

It wasn’t.

Inside absolute humidity was about:

11.2 g/m³

Outside:

9.2 g/m³

So the warm cabin actually contained more water vapour than the air outside.

The Webasto had simply warmed the air enough that the relative humidity percentage dropped.

That is classic campervan physics.

Heat makes the air feel drier.

But the water still exists.

To actually get rid of it, I need ventilation.

Which gives me my new campervan comfort formula:

Not heat + sealed windows.

Not heater on full blast + every vent shut.

Not turn Vanilla into a warm yoghurt pot.

Steady heat.

Controlled fresh air.

Moisture out.

Warmth retained.

That is the sweet spot.

If you want to see another campervan take on the condensation battle and why airflow matters, this is worth a watch too. YouTube

And this is where my incoming Fogstar 105Ah LiFePO4 becomes every bit as important as the heater.

Because autumn comfort is not just about creating heat.

It is about having the confidence to keep the whole van working all night.

The Webasto needs reliable 12V power.

So does the fridge.

So do the lights.

So does the router.

So does everything charging.

Then there are all the background loads quietly nibbling away while I sleep.

My current lead-acid leisure battery can do all this.

But lead acid always makes me think a little more than I want to.

How much have I used?

How low should I let it go?

What is the voltage doing?

Is the heater going to throw a wobble at 4am?

The Fogstar should change that.

Not because lithium is some magical substance.

Because it should give me much more usable capacity and a much flatter, more stable voltage profile.

And for me, the real benefit is psychological.

I want to stop asking:

Can I afford to run this tonight?

And start asking:

How many nights can I run this?

That is a much nicer campervan question.

A Fogstar Drift installation is not particularly glamorous to look at.

It is still fundamentally a battery being fitted into a motorhome or camper electrical system.

But this video gives a useful real-world look at what the lithium upgrade actually involves. YouTube

And this larger Fogstar Drift installation shows the same idea taken to a much bigger scale. Mine will be far more modest at 105Ah, but the principles are the same: usable lithium capacity, dependable 12V power and a much stronger off-grid electrical foundation. YouTube

This is where the whole setup starts feeling properly grown up.

The Webasto gives me:

🔥 heat

🌡️ a stable sleeping temperature

💧 lower relative humidity

🛏️ warmer bedding and surfaces

🌙 confidence on genuinely cold nights

The Fogstar gives me:

🔋 stable voltage

⚡ more usable energy

🌙 dependable overnight capacity

🧊 reliable fridge operation

💡 lights without thinking twice

📱 charging without constantly doing mental arithmetic

The two systems are not glamorous on their own.

But together?

That is the difference between a campervan that can survive autumn and one that actually feels good to live in.

This is the bit I am most excited about.

I do not want a wet autumn evening to become a meeting with the energy budget.

I do not want to sit there thinking:

Do I run the heater?

Do I charge the phone?

Can I leave the lights on?

Is the fridge using too much?

Should I top up the Jackery?

A good campervan should fade into the background.

Arrive.

Park.

Handbrake on.

Webasto on.

Lights on.

Food on.

Feet up.

Sleep.

Wake up warm.

That is the job.

The technology should disappear.

Good systems are boring.

They simply work.

Then there is the Anderson feed from the leisure system into my Jackery setup.

This is one of my favourite bits of the whole power plan.

The feed is only around 90W into the Jackery DC input.

Not spectacular.

Not a fast charger.

But incredibly useful.

Because it means the Fogstar can become the dependable heart of the van while the Jackery units act as portable energy reservoirs for everything else.

Jackery 1000 v2.

Jackery 2000 v2.

Smaller Jackery.

One at a time.

Slowly topped up from the leisure system.

No drama.

No huge current draw.

Just energy moving around Vanilla where I need it.

The Fogstar becomes the house battery.

The Jackery becomes the portable AC and backup power layer.

The 200W solar sits on the roof feeding the system whenever the weather allows.

The Victron Orion feeds it while I drive.

The SmartShunt tells me exactly what is happening.

And because I apparently cannot leave anything alone, I get graphs.

Obviously.

Summer is kind to campervan batteries.

Long days.

Strong solar.

Less heating.

Less lighting.

More time outdoors.

Shorter nights.

Then autumn arrives and the equation reverses.

Less sunlight.

Lower solar harvest.

More heater use.

More lighting.

More charging.

More evenings spent inside.

Longer nights.

The moment energy demand rises is exactly when the sun becomes less useful.

Beautiful.

Thanks, physics.

This is exactly where the Fogstar should earn its keep.

Not because lithium is fashionable.

Because autumn is when I need a proper energy buffer.

Cold is easy.

Put socks on.

Add duvet.

Turn Webasto on.

Done.

Damp is the sneaky one.

Damp gets into bedding.

Damp sits on glass.

Damp creeps into corners.

Damp makes the van smell stale.

Damp creates mould if you ignore it long enough.

And damp makes a perfectly reasonable temperature feel miserable.

That is why these climate readings have been so useful.

They have shown me that the real goal is not:

GET VAN HOT.

It is:

KEEP THE VAN WARM ENOUGH THAT COLD SURFACES STAY AWAY FROM THE DEW POINT, WHILE ALLOWING ENOUGH AIRFLOW TO GET RID OF THE MOISTURE I CREATE.

That is campervan comfort in one sentence.

I love Vanilla.

But let’s not romanticise the engineering too much.

It is still a metal van.

It has windows.

Doors.

A pop-top.

Canvas.

Metal ribs.

Rubber seals.

Glass.

Cold bridges everywhere.

It is not a Scandinavian passive house.

And I do not need it to be.

The trick is not making the Transporter behave like a house.

The trick is making its limitations irrelevant.

That is what good heating does.

That is what good batteries do.

That is what ventilation does.

You do not defeat the cold.

You manage it.

You do not eliminate moisture.

You move it.

You do not create infinite power.

You build enough reserve that it stops mattering.

That is exactly what I want from Vanilla this autumn.

I genuinely cannot wait for the first properly cold autumn night.

Not because I enjoy freezing.

Because I want to see the numbers.

Imagine:

Outside:

7°C

Inside:

18°C

Fogstar:

comfortable

Webasto:

quietly cycling

Humidity:

under control

Solar:

ready for the morning

SmartShunt:

logging everything

Me:

lying under the duvet at 02:17 staring at a graph instead of going to sleep.

That is the dream.

Apparently.

Autumn is engineered comfort.

And I think that is why I am more excited about Vanilla now than I was in July.

Summer gave me warm nights for nothing.

Autumn makes me earn them.

The Webasto gives me control over temperature.

The Fogstar gives me control over energy.

Ventilation gives me control over moisture.

The solar panel gives me recovery.

The Victron gear tells me exactly what is happening.

Together, that should make Vanilla properly usable when the evenings get darker, wetter and colder.

Not just survivable.

Comfortable.

🌡️ 16–20°C for sleeping

💧 40–60% relative humidity where practical

🌫️ more than 5°C between cabin temperature and dew point

🌬️ constant gentle ventilation

🔥 Webasto keeping the cabin stable

🔋 Fogstar providing dependable overnight power

☀️ 200W solar replacing what it can

⚡ Victron Orion recovering energy while driving

📊 SmartShunt feeding my unhealthy appetite for graphs

🔌 Anderson connection topping up a Jackery when useful

That is not just a power system.

It is a comfort system.

After nearly 100,000 interior readings, the most important thing I have learned is that campervan comfort is not one number.

It is balance.

Temperature.

Humidity.

Fresh air.

Surface temperature.

Energy.

Heat.

And confidence.

When all of those things are working together, a Transporter stops feeling like a vehicle.

It becomes a tiny home.

On one of my latest nights, outside air averaged around 14.8°C with humidity near 73%.

Inside Vanilla:

23.1°C.

54% RH.

Nearly 9°C of dew-point headroom.

That is not merely getting through autumn in a campervan.

That is being genuinely cosy.

And with the Webasto now properly part of the plan, plus the Fogstar about to become the heart of the 12V system, I think this little metal hovel is about to become an absolutely brilliant cold-weather escape pod.

Still a van.

Still cramped.

Still full of cables.

Still somehow requiring three times as much equipment as any sensible person would take camping.

But warm.

Dry.

Powered.

Self-contained.

And ready for autumn.

Which is exactly how I want it.

Cold outside. Warm inside. Fogstar underneath. Webasto humming. British weather can do its worst. 🍂🔥🔋🚐