PROFESSOR SPARK’S BLUE BOX THEORY

Why one chunky blue box might completely change the way Vanilla recovers her energy

There are campervan upgrades that announce themselves with theatre.

New wheels. Fresh tyres. Lithium under the seat. Solar on the roof. A heater firing up on a freezing evening.

And then there are upgrades that look rather less exciting at first glance.

A black box. A blue label. A mains lead.

Except this particular black box has 25 amps hiding inside it.

And Professor Spark has been staring at it.

⚡

The device in question is the Victron Energy Blue Smart IP65 12V/25A 230V battery charger, the far more muscular sibling of the little 10A Blue Smart charger that has already proved itself aboard Vanilla.

The 10A works.

It works beautifully.

But after fitting Vanilla's 105Ah Fogstar LiFePO₄ battery, surrounding it with Victron kit and watching the system through the SmartShunt, one question started humming around the NIX laboratory.

What happens if we stop sipping electricity and start pouring it in properly?

Welcome back to Professor Spark's laboratory.

The goggles are on.

The SmartShunt is watching.

And today's number is:

Vanilla now has a remarkably capable electrical system.

At the centre sits the Fogstar 105Ah LiFePO₄ battery.

Roughly:

12.8V nominal 105Ah ≈1,344Wh stored energy

That battery runs Vanilla's everyday 12V world.

The fridge.

Lighting.

Television.

USB charging.

The Webasto controls and blower.

All those small loads that quietly turn a campervan from a steel box into a warm little off-grid home.

The Fogstar can then be replenished in several different ways.

From the roof through the Victron SmartSolar MPPT 75/15.

From the alternator while driving through the Victron Orion Smart 30A DC-DC charger.

And from 230V through a Victron Blue Smart mains charger.

My existing Blue Smart is the smaller 10A version.

It has already demonstrated something important.

Give Vanilla AC electricity and I can transfer that energy directly back into the Fogstar through a proper smart lithium-capable charger.

Simple.

Reliable.

Bluetooth monitored.

Very useful.

But Professor Spark has now noticed that Victron makes something rather more interesting.

Twenty-five amps.

Not a marginal upgrade.

Not 12A.

Not 15A.

25A.

And suddenly the mains-charging side of Vanilla's electrical system starts looking considerably more serious.

Before Professor Spark starts vandalising the laboratory blackboard with equations, let's establish exactly what this charger family is.

Victron Energy's own introduction to the Blue Smart IP65 charger:

That is an official Victron Energy video introducing the Blue Smart IP65 range and its built-in Bluetooth capability. YouTube

And that matters.

Because this isn't an anonymous charger with a sticker on the front and a suspiciously optimistic eBay description.

This is part of Victron's established charging ecosystem.

Rugged enclosure.

Smart charging logic.

Bluetooth.

VictronConnect.

A product designed to exist around vehicles, batteries and real electrical installations.

And sitting within that range is the version Professor Spark has now put a large red circle around:

12V / 25A

Then there is the Amazon listing.

This isn't the engineering source. Victron remains the proper source for specifications and charging behaviour.

But Amazon provides useful independent retail confirmation that the exact UK model exists as a readily available product:

Victron Energy Blue Smart IP65 12V/25A 230V UK

https://www.amazon.co.uk/dp/B09KKM6P3V/

That turns the Amazon page into something more useful than a Buy button.

Professor Spark files it under:

The 25A charger isn't hypothetical.

It isn't an industrial curiosity.

It isn't something buried on page 94 of a distributor catalogue.

It is a genuine retail version of the Blue Smart IP65 charger.

And that makes the next question much more interesting.

Not:

Does it exist?

But:

Amps by themselves are not terribly exciting.

So let's turn them into power.

My Fogstar charging setup revolves around roughly the 14V region.

At 14.2V, 25 amps represents approximately:

14.2 × 25 = 355 watts

That gives us around:

Now compare that with the smaller 10A charger.

14.2 × 10 = 142W

And Vanilla's 30A Orion:

14.2 × 30 = 426W

Suddenly things line up very neatly.

And that table is where Professor Spark's eyebrow goes up.

Because the 25A mains charger is getting surprisingly close to the power territory of the 30A alternator charger.

That means Vanilla could effectively have two substantial high-current charging routes.

Driving?

Around 30A available from the Orion.

Plugged into AC?

Up to 25A available from the Blue Smart.

That is a very different electrical architecture from relying on one little 10A charger as an occasional rescue tool.

Let's use the Fogstar's 105Ah nominal capacity as a crude measuring stick.

If a theoretical completely empty battery could accept maximum current throughout the entire cycle:

At 10A:

105 ÷ 10 = 10.5 hours

At 25A:

105 ÷ 25 = 4.2 hours

At 30A:

105 ÷ 30 = 3.5 hours

Real charging is not that neat.

There are loads running.

Voltage rises.

Charge stages change.

Current eventually reduces.

The battery management system exists for good reason.

There are losses.

So those aren't promised recharge times.

They're useful scale.

And the scale tells us something very important.

10A is an overnight charger.

25A begins to become a rapid recovery charger.

That distinction matters.

Now forget the laboratory.

Let's put Vanilla somewhere she actually belongs.

A winter pub stop.

Outside temperature dropping.

Webasto running.

Fridge quietly humming.

Lights on.

Phone charging.

Maybe the television running.

There has been poor winter solar all day.

By morning the Fogstar is lower than I'd ideally like before another night off-grid.

With the 10A charger, a couple of hours on mains is useful.

But gentle.

At 25A, those same two hours could theoretically shift:

25A × 2h = 50Ah

into the battery before charging behaviour and losses are considered.

Fifty amp-hours is nearly half the nominal capacity of the Fogstar.

That is no longer a top-up.

That is a serious recovery session.

Professor Spark officially names this:

Pub.

Dinner.

Electricity.

Fogstar recovering outside.

Science rarely gets better than this.

Now we enter the slightly more eccentric end of Professor Spark's laboratory.

Because AC does not necessarily have to come from a campsite bollard.

Vanilla carries separate Jackery power stations.

They are not permanently tied into the Fogstar system.

I deliberately think of them as separate energy reservoirs.

That creates an emergency energy path:

Jackery battery → inverter → 230V AC → Victron charger → Fogstar

At first glance that looks electrically bonkers.

Battery.

Inverter.

Charger.

Battery.

And yes, there are conversion losses.

Professor Spark is fully aware that physics sends an invoice every time electricity changes form.

But efficiency is not the only measure of usefulness.

If the Fogstar needs energy and there are several kilowatt-hours sitting inside portable Jackery batteries, then having a reliable bridge between those two systems is extremely useful.

The 10A charger already proved that idea.

The 25A potentially transforms it.

Instead of dribbling energy from the Jackery into the Fogstar, you could potentially move it at several hundred watts.

That makes the Jackery fleet more than a collection of portable AC batteries.

It becomes a potential strategic reserve for Vanilla's native 12V system.

Now Professor Spark is properly awake.

Twenty-five amps are useful.

Twenty-five amps you can watch are much more fun.

VictronConnect is one of the reasons this charger makes sense in Vanilla.

Victron's own video covering Blue Smart charger history and settings in VictronConnect is here:

It shows the sort of charging history and configuration visibility available through the app. YouTube

And this matters enormously to the NIX experiment.

Because I don't want to plug a charger in and merely assume things are happening.

I want to see:

Battery voltage.

Charge stage.

Current.

History.

Settings.

Behaviour over time.

Then compare what the charger claims it is doing against what Vanilla's SmartShunt actually sees.

That is where this stops being a product review and becomes a proper experiment.

Professor Spark has one simple laboratory rule:

One of the things I've gradually come to appreciate is how the Victron equipment begins working as a family.

Vanilla now has:

SmartSolar managing solar.

SmartShunt measuring the battery.

Orion Smart managing alternator charging.

Blue Smart handling mains charging.

Different jobs.

Same basic ecosystem.

Same language.

Same philosophy.

And increasingly, the same phone.

Instead of Vanilla's electrical installation feeling like a collection of unrelated boxes added over several years, it starts behaving like one energy system.

Professor Spark approves.

The Blue Smart belongs to Victron's IP65 family.

That sounds like a dull technical designation until you remember where this equipment lives.

A campervan is not a clean laboratory.

It is a moving workshop.

Dust.

Damp.

Boots.

Camping gear.

Condensation.

Storage lockers.

Cables getting packed away.

Doors opening in the rain.

An occasional cup of tea in dangerously close proximity to electricity.

The rugged casing makes sense.

This feels like vehicle equipment rather than something designed to sit permanently next to a domestic socket.

And that suits Vanilla perfectly.

The 10A and 25A chargers fundamentally do the same job.

But aboard Vanilla they would have quite different roles.

Gentle.

Compact.

Low AC demand.

Ideal overnight.

Excellent for maintenance.

Perfectly good as an emergency charger.

A very useful tool.

Faster.

More substantial.

Much better suited to deep recovery.

Closer to the charging speed of the Orion.

More interesting for Jackery-to-Fogstar energy transfer.

Potentially capable of replacing a serious amount of capacity in just a few hours.

Neither charger makes the other obsolete.

They are simply different tools.

A teaspoon and a ladle both move soup.

Only one gets dinner served quickly.

This is where Vanilla's electrical system starts looking rather beautiful.

While driving:

30A Orion Smart

While connected to mains:

25A Blue Smart

When the sun is shining:

SmartSolar MPPT

Different circumstances.

Different source.

Same Fogstar.

That means Vanilla no longer relies on one particular way of finding electricity.

Drive and charge.

Park and use solar.

Plug in and charge.

Use stored Jackery energy if necessary.

This is the point where I've stopped thinking purely about battery capacity.

I now think about:

A large battery is excellent.

But a battery that can be replenished from several different sources is far more powerful in the real world.

Fogstar energy capacity:

approximately 1.344kWh

Potential Blue Smart 25A charging power near 14.2V:

approximately 0.355kW

A deliberately simplistic calculation gives:

1.344 ÷ 0.355 ≈ 3.8 hours

Again, that is not a promise of a full recharge in 3.8 hours.

Real lithium charging does not operate at full theoretical power from empty to full without variation.

But it reveals the scale.

The charger isn't in trickle-charge territory.

It is potentially capable of moving energy into a campervan leisure battery in hours rather than most of a day.

That changes how useful a short mains opportunity can be.

There is an important point here.

A charger having 25A available does not mean Professor Spark blindly connects it and shouts:

The battery remains the boss.

The Fogstar must be charged within its permitted current and voltage limits.

The Victron profile must be configured correctly for LiFePO₄.

My current lithium charging setup uses figures around:

14.20V absorption

13.50V float

And the rest of the installation must be capable of handling the current properly.

That means:

Correct cable size.

Correct connectors.

Correct fusing.

Sound terminations.

Battery limits respected.

Charger ventilation.

A suitable 230V supply.

Professor Spark enjoys experimentation.

He also enjoys not setting fire to Vanilla.

This is another place where 25A changes the conversation.

Ten amps is modest.

Twenty-five amps deserves a proper connection.

For Vanilla, a correctly specified Anderson-style connector is attractive because it makes the charger feel like part of a system rather than something temporarily clipped onto the battery.

The dream workflow is:

Take charger out.

Connect Anderson.

Connect AC.

Open VictronConnect.

Charge.

Disconnect.

Pack away.

No crocodile clips.

No wrestling with battery terminals.

No temporary wiring hanging around underneath the seat.

Just a proper, repeatable procedure.

That is how I want Vanilla's electrical system to evolve.

This is another reason the dedicated Victron charger makes sense.

Vanilla's original conversion used the Sargent EC155.

That system was designed in a different battery era.

Once the Fogstar lithium battery arrived, I isolated the original Sargent mains charger rather than asking an older charging setup to manage a completely different battery chemistry.

The Sargent can still perform the jobs it is good at.

But battery charging becomes the responsibility of equipment designed for the lithium installation.

That division feels right.

Original campervan architecture preserved.

Modern charging added properly.

Old and new working alongside each other rather than fighting.

Professor Spark writes this on the blackboard:

Sunlight falls on Vanilla.

SmartSolar turns it into useful battery energy.

Engine running.

Orion takes alternator energy and charges the Fogstar.

Grid electricity.

Campsite EHU.

Home socket.

Potential Jackery-generated AC.

Blue Smart handles it.

That is not just redundancy.

It is freedom.

Because no single source has to save the day.

Poor solar?

Drive.

Not driving?

Plug in.

No mains?

Use stored power.

Good sunshine?

Let the roof do the work.

The system adapts.

And the Fogstar is only one part of Vanilla's total energy picture.

Across the Fogstar and the separate Jackery power stations, I'm carrying roughly 5kWh of stored energy.

That matters.

The Fogstar is Vanilla's native electrical heart.

The Jackerys are the portable reserve.

The solar panel is the background generator.

The alternator is the moving generator.

And the 25A charger potentially becomes the high-capacity bridge between the AC world and the Fogstar.

Suddenly this doesn't feel like a campervan with a leisure battery.

It feels more like a tiny mobile microgrid.

Professor Spark has entered dangerous levels of happiness.

Summer solar can make almost any respectable campervan electrical system look clever.

Winter is where the truth lives.

Short days.

Low sun.

More heating.

More lights.

Long evenings inside.

More time using the television.

Less time with the roof panel bathing in glorious sunshine.

That is exactly where fast mains recovery becomes valuable.

Imagine two nights off-grid.

Fogstar has taken a proper beating.

Then an opportunity appears to use mains for three hours.

With the 10A charger:

Useful.

With the 25A charger:

Potentially a major restoration of battery capacity.

That could mean arriving at the next pub stop with the battery effectively reset rather than merely improved.

And that changes the way you travel.

If the 25A charger joins Vanilla, I don't want to plug it in once and write:

"Yep. Works."

That would be criminally boring.

I want a proper test.

Start the Fogstar at approximately:

Run Vanilla normally.

Fridge on.

Webasto operating if conditions permit.

Normal background loads.

Connect the 25A Blue Smart.

Then record:

SOC.

Battery voltage.

SmartShunt current.

Charger current.

AC input power.

Jackery draw if used as the AC source.

Temperature.

Elapsed time.

Then stop around:

That represents approximately 60% of the battery's nominal capacity.

For a 105Ah battery:

≈63Ah

At an idealised 25A:

63 ÷ 25 ≈ 2.5 hours

Reality will differ.

That's precisely why I want to test it.

Because the interesting article isn't:

Victron says 25A.

The interesting article is:

Now we're doing science.

And the SmartShunt will make this even better.

Instead of remembering vaguely that the battery "charged quite quickly", I'll be able to look at actual current flow.

Start time.

End time.

SOC change.

Energy moved.

Loads running.

Voltage behaviour.

Then compare:

10A Blue Smart

versus

25A Blue Smart

versus

30A Orion

Three different routes into the same battery.

That could produce one of the most useful real-world Vanilla tests yet.

Not theoretical brochure numbers.

Actual campervan data.

This entire project has changed how I think about campervan electricity.

With the old AGM battery, energy always felt precious.

Will the heater last?

Will the fridge be okay?

How much solar did I get today?

Do I need to drive?

Every watt felt important.

Lithium changed that.

The 200W solar installation changed it again.

The Jackery fleet changed it again.

The Orion changed it again.

And the more reliable ways I create to move energy back into the system, the less the electrical system dictates what I do.

That is exactly how it should be.

I don't want to plan trips around the battery.

I want the battery system to support the trip.

Power: ⚡⚡ Compactness: ⚡⚡⚡⚡⚡ Overnight usefulness: ⚡⚡⚡⚡⚡ Emergency ability: ⚡⚡⚡ Professor Spark excitement: ⚡⚡⚡

Power: ⚡⚡⚡⚡ Recovery potential: ⚡⚡⚡⚡⚡ Winter usefulness: ⚡⚡⚡⚡⚡ Jackery experiment potential: ⚡⚡⚡⚡⚡ Professor Spark excitement: ⚡⚡⚡⚡⚡⚡⚡⚡⚡

There are only five marks available.

Professor Spark has ignored this.

If you're following this experiment and want to understand the hardware properly, these are the two videos I'd start with.

Victron Energy: Blue Smart IP65 Charger

Official introduction to the Blue Smart IP65 family and built-in Bluetooth. YouTube

Victron Energy: History and settings for Blue Smart Chargers in VictronConnect

A useful look at the app side of Blue Smart charging, including charger history and settings. YouTube

On NIX Drones, those plain YouTube URL lines can sit directly in the article so the site can render them as proper video embeds.

The Victron Blue Smart IP65 12V/25A sits in a fascinating position inside Vanilla's evolving electrical system.

It isn't some vast inverter-charger installation.

It doesn't require redesigning the entire van.

It is portable.

Simple.

Smart.

And potentially capable of delivering around 355W of DC charging power near 14.2V.

That gets remarkably close to Vanilla's 30A Orion DC-DC system.

Which means the 25A charger could turn mains electricity from a gentle overnight top-up into something far more useful.

A real recovery tool.

A winter tool.

A pub-stop tool.

A campsite tool.

A home charging tool.

And perhaps most interestingly, a way of turning Vanilla's large Jackery reserve into emergency energy for the Fogstar.

The 10A Blue Smart proved the concept.

The 25A version could turn that concept into serious capability.

And that is why Professor Spark is interested.

Not because the number on the box is bigger.

Because bigger current changes what is possible.

A depleted Fogstar.

A few hours of electricity.

A cold night ahead.

Connect the charger.

Open VictronConnect.

Watch the amps rise.

And somewhere inside Vanilla, more than three hundred watts of electrical energy starts marching back towards the battery.

Beautiful.

Battery: Fogstar 105Ah LiFePO₄ Nominal battery energy: ≈1.34kWh Existing Blue Smart: 10A Candidate Blue Smart: 25A Approximate 25A charging power at 14.2V: 355W Orion DC-DC: 30A Solar: 200W roof panel through SmartSolar 75/15 Portable reserves: Jackery fleet Combined Vanilla energy ecosystem: roughly 5kWh Mission: stop worrying about batteries and go somewhere interesting.

Amazon UK:

https://www.amazon.co.uk/dp/B09KKM6P3V/

Victron Blue Smart IP65:

https://www.victronenergy.com/chargers/blue-smart-ip65-charger

Official Victron video:

VictronConnect Blue Smart video:

And Professor Spark is left with one very simple question.

I suspect the answer involves a SmartShunt, a stopwatch, a Jackery, several graphs and a completely unnecessary amount of excitement.