Rappy is my 2007 Mercedes Sprinter and has become far more than just a campervan. It is an ongoing engineering project, test platform and fully self-contained off-grid vehicle that I have developed and rebuilt around the way I actually travel and live.
When I bought Rappy, it already had around 415,000 miles on the clock. One of the first things I did was inspect the underside carefully, and despite the mileage the structure underneath was in good condition, which made it a worthwhile base for the project.
Since then, Rappy has been heavily upgraded mechanically, electrically and internally.
Mechanical Upgrades
The original engine was replaced with a lower-mileage donor engine from a newer Sprinter, giving the van a much stronger mechanical base.
Rappy has also been uprated to 4,050 kg by SVTech, allowing for the additional equipment, water capacity, batteries and systems fitted during the conversion.
The rear suspension has been upgraded with rear air assistance, helping with ride quality and levelling when fully loaded.
Lightweight Interior Construction
The interior has been built using lightweight plywood wherever possible to keep unnecessary weight down while still maintaining strength and durability.
The living space includes:
- full shower
- toilet
- kitchen
- two-ring induction hob
- storage throughout
- two swivel captain’s seats
- cinema projector and screen
The aim has always been to make Rappy comfortable enough for long-term use without turning it into something overly complicated or impractical.
Solar, Victron & Electrical System
Rappy has a full Victron Energy electrical system designed for serious off-grid use.
The system includes:
- Victron MultiPlus-II 5000VA inverter/charger
- 2 × Victron Orion XS 50A DC-DC chargers taking charge from the engine/alternator
- Victron Cerbo GX
- 7-inch Victron GX Touch display
- 1,256Ah lithium battery bank
- 515W self-tracking solar panel
- Full Victron integration with Home Assistant
The electrical system is designed to give Rappy a very large usable energy reserve, with charging available from solar, the engine and mains hookup.
The MultiPlus-II 5000VA provides enough inverter capacity to run high-demand equipment such as the induction hob, washer-dryer and other 230V appliances.
The two 50A Orion XS DC-DC chargers allow the lithium battery bank to be charged from the engine while travelling, giving up to around 100A of DC-DC charging capacity when conditions allow.
The Cerbo GX and 7-inch GX Touch display provide central monitoring of the Victron system, while Home Assistant integration allows electrical information to be brought together with the rest of Rappy’s automation, heating, water and control systems.
With 1,256Ah of lithium battery capacity, the system is built around extended off-grid use rather than simply providing basic campervan power.
Heating, Hot Water and Air Conditioning
Rappy uses a multi-source hydronic heating system rather than relying on a single heater.
At the heart of the system is a diesel hydronic heater, which heats a coolant circuit running through the van. That heated coolant can then be used for both space heating and domestic hot water.
For hot water, the system feeds a 20-litre calorifier mounted at the rear of Rappy. The calorifier can be heated in three different ways:
- from the diesel hydronic heater
- from engine heat while driving
- from a 3 kW electric immersion heater when connected to mains hookup
That means we can produce hot water whether we are driving, parked off-grid, or plugged into a campsite supply.
The same coolant circuit also supplies two separate heat exchangers, one at the front of the van and one at the rear. This gives Rappy a genuine two-zone heating system, allowing the front and rear areas to be heated independently depending on where the heat is actually needed.
While travelling, waste heat from the engine can also be circulated through those heat exchangers, so the living area can be warmed without having to run the diesel heater.
Rappy also has a small heated towel rail connected into the same hydronic circuit, adding a useful bit of background heat in the washroom area and helping towels dry more quickly.
When we are on electric hookup, we can select the 3 kW electric heater as the heat source instead of burning diesel. That gives us a very flexible system with multiple layers of redundancy.
In practice, Rappy therefore has three different ways of producing hot water and heating:
- diesel hydronic heating
- engine waste heat
- 3 kW mains electric heating
That flexibility is one of the things I wanted from the build. If one heat source is unavailable, inefficient for the conditions, or simply unnecessary, there is always another option available.
For cooling, Rappy also has an air-conditioning system, allowing the living space to be cooled as well as heated, which makes the van much more usable throughout the year.
Washing Machine and Dryer
One feature that always gets a reaction is the Daewoo 3 kg automatic washer-dryer fitted in the van.
For longer trips and full-time use, having a proper washing machine makes a huge difference.
It is one of those things that initially sounds excessive in a campervan, but once you’ve lived with one it becomes difficult to imagine travelling without it.
Water System
Rappy carries approximately 250 litres of fresh water, giving the van a substantial off-grid water capacity.
Waste water is stored in a 110 litre waste tank.
The waste tank uses a remotely operated gate valve with a linear actuator, which is controlled through Home Assistant.
That means the waste valve can be opened and closed electrically rather than having to manually operate a valve underneath the van.
The water pump is also integrated into the automation system.
Home Assistant and AI Control
A major part of Rappy is the automation system.
Home Assistant is effectively the central control system for the van and is used to manage:
- internal lighting
- external lighting
- water pump
- heating
- air conditioning
- Victron system information
- waste tank valve
- CCTV
- ventilation
- other electrical systems
Alexa voice control is also integrated, allowing lighting and other functions to be controlled by voice.
The long-term aim is to make the van increasingly intelligent, with AI helping to monitor energy use, heating, water, solar production and other systems.
CCTV and Security
Rappy has a 360-degree CCTV system, providing coverage around the entire vehicle.
This gives both security and situational awareness when parked overnight or in unfamiliar locations.
Custom MaxxAir Fan Control
The roof ventilation system uses a modified MaxxAir fan.
Rather than relying solely on the original electronics, I designed and built my own PCB control system for it.
This allows the fan to be integrated more closely into the rest of Rappy’s automation system and controlled alongside the heating and ventilation setup.
Entertainment
Rappy also has a proper cinema setup.
A projector and cinema screen allow the inside of the van to be turned into a comfortable movie space without needing a large permanent television taking up wall space.
Together with the swivel captain’s seats, it makes the front and living areas much more versatile.
Exterior
The van has been finished using Raptor protective coating, giving the bodywork a tough, distinctive finish that suits the way the vehicle is used.
Rappy is not intended to be a showroom camper.
It is designed to be driven, travelled in, experimented with and continually improved.
An Ongoing Engineering Project
Rappy is never really finished.
It has become a test bed for ideas involving solar power, battery systems, automation, electronics, heating, water management and off-grid living.
Some projects work exactly as planned. Others get redesigned several times before I am happy with them.
That is part of the reason I built this website and my YouTube channel — to document those projects, explain how the systems work and hopefully give other people ideas for their own builds.
Rappy is effectively a mobile engineering project that just happens to also be my Home.