2021 Iveco Daily XLWB: Complete Off-Grid Electrical, Heating, Air Conditioning and Window Installation

Some conversions need a new battery. Others need almost everything. Here at Van Junkies in Gosport, Hampshire, we design and install off-grid electrical systems for campervans and motorhomes, and this 2021 Iveco Daily Extra Long Wheelbase was one of the largest single projects to come through our workshop. This case study covers a complete campervan conversion electrical installation alongside heating, air conditioning, ventilation and four new windows. A full campervan off-grid installation is the combination of battery storage, inverter capacity, multiple charging sources and the onboard equipment that makes a vehicle habitable year-round. If you want to know what your own build needs, our Kit Recommender will point you towards the right power setup.

Van Junkies installed a complete Victron Energy 12V and 230V system in a 2021 Iveco Daily XLWB, built around a 628Ah Fogstar Drift lithium battery, a Victron MultiPlus-II 12V 3000VA 120A inverter/charger, a Victron Orion XS 12/12-70A DC-DC charger and a 390W roof solar array running through a Victron SmartSolar MPPT 150/35 controller. Alongside the electrics, the team fitted a Dometic FreshJet FJX4 2200 roof air conditioner, a Truma Combi D4E diesel and electric heating and hot water system, a Maxxair MaxxFan Deluxe roof vent, and four new windows.

The build at a glance:

• Battery Capacity: A Fogstar Drift 12V 628Ah lithium leisure battery, holding approximately 8kWh of nominal stored energy.
• 230V Power: A Victron MultiPlus-II 12V 3000VA 120A inverter/charger with a Digital Multi Control panel.
• Charging While Driving: A Victron Orion XS 12/12-70A DC-DC charger, drawing from the alternator on every journey.
• Solar: Three roof-mounted monocrystalline panels totalling 390W, through a Victron SmartSolar MPPT 150/35 controller.
• Climate: A Dometic FreshJet FJX4 2200 roof air conditioner, 2200W cooling with a 1000W heating function.
• Heating and Hot Water: A Truma Combi D4E, running on diesel or on mains electricity when hooked up.
• Ventilation: A Maxxair MaxxFan Deluxe powered roof vent with remote control.
• Windows: Two bonded privacy-tinted windows and two top-hung opening adventure windows with blinds.

1️⃣ The Brief: Much More Than an Electrical Installation

Some projects involve fitting a new battery or upgrading an existing system. This one was a different order of work entirely.

Our customer asked us to transform the vehicle with a powerful off-grid electrical system alongside major upgrades to its heating, cooling, ventilation and windows. The brief was a vehicle with the comforts of a modern motorhome and the electrical infrastructure to support extended adventures away from hook-up.

An XLWB Iveco Daily offers an enormous amount of potential living space, so the challenge was never whether the equipment would fit. It was integrating several sophisticated systems into one vehicle correctly: extensive electrical work, precision cutting of the bodywork, roof-mounted installations, careful cable routing, and getting different technologies to coexist.

2️⃣ The Power System: 628Ah of Lithium and 3000VA of Victron

For a vehicle this size, running air conditioning, heating and a full range of domestic loads, the electrical system had to deliver substantial power reliably. We designed it around three requirements: generous battery storage, powerful 230V capability, and flexible charging.

At the centre sits a Fogstar Drift 12V 628Ah lithium leisure battery, providing approximately 8kWh of nominal stored energy. That is a serious amount of capacity for a campervan, and it is what makes extended periods away from hook-up practical. Lithium offers more usable capacity than lead-acid from the same nominal rating, accepts a far faster charge, and lasts considerably longer.

To turn that into mains-style electricity, we installed a Victron Energy MultiPlus-II 12V 3000VA 120A inverter/charger. It powers suitable 230V appliances from the lithium battery when the vehicle is not connected to campsite electricity, and on hook-up it reverses into a powerful battery charger at up to 120A, subject to the configured limits. We also fitted a Victron Digital Multi Control panel, giving the customer direct control of the inverter/charger and its AC input current limit.

3️⃣ Charging: Orion XS 70A and 390W of Solar

A 628Ah battery is only as useful as your ability to refill it. This van has three independent ways of doing that, which is the real point of the design.

The Victron Orion XS 12/12-70A DC-DC battery-to-battery charger lets the alternator contribute whenever the van is driven. It regulates the process and delivers a charging profile appropriate to lithium, rather than connecting the two batteries directly. At up to 70A it can replace a significant amount of energy over a longer journey: three hours at a sustained 70A would theoretically return around 210Ah, before allowing for changing charge rates and system losses.

On the roof, three monocrystalline panels totalling 390W feed a Victron SmartSolar MPPT 150/35 charge controller, which continually adjusts its operating point to pull the most available energy from the array. Through the brighter months 390W makes a useful contribution to daily consumption. Output varies with weather, season, shading and orientation, so it is one leg of the strategy rather than the whole of it.

Pro Tip: Three charging sources beats one big one. If your trips involve long stays and short drives, solar earns its keep; if you cover distance between stops, the DC-DC charger does the heavy lifting. Our full power system kits are built around getting that balance right for how you actually travel.

4️⃣ The Part You Cannot See: Distribution and Protection

Installing a large lithium battery and a powerful inverter takes far more than connecting a positive and a negative. High-current systems need correctly specified cable, secure terminations, appropriate circuit protection and reliable distribution. Get it wrong and the first symptom is usually smoke.

For this Iveco Daily we installed:

• Battery Cabling: Heavy-duty 95mm², with additional 50mm² and 10mm² power cable.
• Distribution: Victron 250A covered busbars and a Blue Sea Systems 12-way DC blade fuse block.
• Protection: A Blue Sea Systems 400A Class-T fuse and holder, plus MEGA fuse protection and holders.
• Isolation: A Victron 275A battery isolation switch.
• 230V Side: A consumer unit with circuit protection, external mains hook-up connection, and appropriate cabling and enclosures.

Our engineers had to work through cable routing, available space, accessibility, equipment positioning and the demands of each component. Every circuit is labelled at the rail, which is the difference between a system someone can work on in five years and one they have to trace from scratch.

5️⃣ Four New Windows: Precision Bodywork on a Large Panel Van

Alongside the electrics, we fitted four new windows: two bonded privacy-tinted units and two Adventurer top-hung opening windows with black blinds.

The bonded privacy windows give a clean, finished appearance and let natural light in, while the tinted glass adds privacy, which matters in a van used for overnight stays. The top-hung opening windows add something the bonded units cannot: ventilation you can leave open. Their low-profile curved frames sit tight to the bodywork.

Cutting four substantial openings into the bodywork of a 2021 Iveco Daily is not something to undertake lightly. Each window needs careful measurement and positioning before the first cut, and once the metal is cut there is very little room for error. The openings must be properly prepared, the windows correctly fitted, and the sealing and bonding completed with care.

Pro Tip: Plan your window positions around the interior layout before anything is cut, not after. A window that lands behind a wardrobe or halfway across a bed is a mistake you cannot undo.

6️⃣ Dometic FreshJet FJX4 2200: Air Conditioning That Earns Its Place

Keeping a large campervan comfortable in warm weather is harder than it sounds. Even in the UK, the inside of a parked vehicle climbs quickly in sunshine. The Dometic FreshJet FJX4 2200 provides 2200W of rated cooling capacity, and the model we fitted also includes a 1000W heating function.

Fitting it involved more than bolting a unit to the roof. We supplied a vehicle-specific adapter frame designed for the Iveco Daily roof profile, along with the appropriate Dometic air distribution unit, then planned the position, prepared the mounting area and integrated it into the electrical installation.

7️⃣ Truma Combi D4E: Heating and Hot Water in One Unit

Comfort is not only about staying cool. For year-round travel, dependable heating and hot water matter just as much, so we installed a Truma Combi D4E combination heater, which provides space heating and domestic hot water from one integrated unit.

The D4E runs on diesel, with an electric operating capability when a suitable mains supply is available. That makes it a versatile choice for a large campervan. The diesel function heats the living space without relying on the leisure battery for electrical resistance heating, which matters most in cold weather when the van is parked away from campsite facilities and solar output is at its lowest.

Bringing space heating and hot water together in one appliance also saves space and weight compared with running two separate systems, which in a conversion is never a small consideration.

8️⃣ Ventilation and the Battle for Roof Space

A Maxxair MaxxFan Deluxe powered roof vent completes the climate setup. It circulates air through the living space, clears warm or stale air, and runs from the remote control. Paired with the two opening windows, it moves fresh air through the van at a tiny fraction of the air conditioner energy draw, which makes it the sensible first choice on all but the hottest days.

Fitting it meant cutting and preparing another roof opening, securing the unit and integrating it into the 12V system. With an air conditioner, three solar panels and a powered fan all competing for the roof, positioning had to be planned as one job rather than three. Shade one corner of a solar panel with an AC unit and you lose more output than most people expect.

This is the part of a multi-system project that is easy to underestimate. Electrical engineering, vehicle bodywork, roof installations, heating and hot water, and the integration of all of it. Each is a substantial job on its own; doing them together takes planning and an understanding of how the systems interact.

9️⃣ Frequently Asked Questions

Can you run campervan air conditioning off a leisure battery?

Yes, with a large enough battery and inverter, but not indefinitely. This Iveco Daily has 628Ah of lithium and a 3000VA inverter, which is about as capable as campervan installations get, and air conditioning is still the single heaviest load on board. Running time depends on the unit consumption, other loads and what is recharging the battery at the time. For extended use, mains hook-up is the practical answer.

How long will a 628Ah lithium battery last off-grid?

A 628Ah 12V lithium battery holds approximately 8kWh nominal, of which around 7.2kWh is a reasonable planning figure. At 1kWh a day that is roughly a week; at 2kWh a day, three to four days. Solar and alternator charging extend those figures considerably, and high-draw appliances such as air conditioning shorten them sharply.

Can you fit windows to an Iveco Daily?

Yes. We fitted four to this XLWB: two bonded privacy-tinted windows and two top-hung opening units. The work involves measuring and positioning each opening, cutting the bodywork, preparing the aperture and bonding or fixing the window with the correct sealing procedure. The measuring matters more than the cutting, because once the metal is cut there is no undoing it.

Is diesel heating better than gas in a campervan?

For many conversions it is more convenient, because diesel heating draws from the vehicle own fuel supply rather than gas bottles that need swapping and storing. The Truma Combi D4E in this build also runs on mains electricity when hooked up, so the customer can choose whichever suits the pitch. Gas still has its place, particularly where an existing gas system is already fitted.

Why fit a higher-output DC-DC charger?

Because charge rate decides how much a journey is worth. A 70A DC-DC charger returns more energy per hour of driving than a 50A one, which matters when the battery bank is large and the drives between stops are short. The limit is the vehicle alternator and operating conditions, so the charger should be specified against the vehicle rather than chosen purely on headline amps.

How much solar can you fit on a large panel van roof?

Less than the roof area suggests, once air conditioning and ventilation are accounted for. This Iveco Daily carries 390W across three panels alongside a Dometic FreshJet air conditioner and a Maxxair roof vent. Shading is the other constraint: a panel partly shaded by a roof unit loses disproportionately more output than the shaded area alone, so layout matters as much as panel count.

Do you need an inverter for 230V power in a campervan?

You do, if you want mains sockets to work away from hook-up. An inverter converts 12V battery power into 230V AC. This build uses a Victron MultiPlus-II 3000VA, which also works in reverse as a 120A battery charger when mains is available, so one unit covers both directions.

Where does Van Junkies carry out campervan conversions?

At our workshop in Gosport, Hampshire. We work on campervans, motorhomes and marine installations, from single lithium battery upgrades to multi-system projects like this Iveco Daily, covering electrical systems, heating, air conditioning, ventilation and windows.

🔟 Planning a Major Campervan Upgrade or Conversion?

We are best known for specialist campervan and motorhome electrical installations, but as this Iveco Daily shows, our workshop capabilities go considerably further. Complete off-grid electrical systems, lithium battery upgrades, air conditioning, diesel heating, roof ventilation and professionally installed windows.

Every vehicle and every customer is different, so we take the time to understand how you intend to use the van before recommending equipment. We do not sell oversized systems or kit you will not use. If your build does not fit a standard kit, our team offers a free bespoke campervan and motorhome electrical and solar design service.

Planning something ambitious? Call our UK team on 023 935 52732 or WhatsApp us via the website chat and tell us what you have in mind.