Introduction
The intension of this page is to highlight the general specification we have used for the conversion to a motor home, I am sure things will change during the works as choices are made on specific equipment
Brief outline
The vehicle is to be used predominantly to carry two adults in relative comfort over various terrain including of-road but not desert and will cover approximately 20,000 miles per annum for a period of 10 years, potentially 200,000 miles on a full time basis. The unit is to be able to sleep four adults.
Corner stones of the design and construction are:
Easy access to serviceable components Efficiency of electrical equipment coupled with a long service life Durability of surfaces and fabrics A common sense approach to construction
Base vehicle
Vehicle type: 1992 Mercedes 814DA chassis cab, left hand drive
Wheelbase: 3.75 m (to be stretched to 4.5m)
General construction
Approximate overall finished height: 3.7metres (12 foot)
Overall finished body width: 2.4m
Overall finished length approximately 8.0 metres
Departure angle of at least 15 degrees
Body to be attached to the chassis by an appropriate torsion reducing mounting
Full length heated under floor storage compartment for tanks, equipment and general storage
Exterior walls, roof and floor to have a wall insulation of at least 55mm, special attention is to be paid to the insulation factors of doors, windows and roof hatches. Cold bridges are to be avoided at all costs, the exterior surface to be durable GRP finished,
1. Chassis cab
The chassis is to be stretched to achieve a wheelbase of 4.500 metres and an overhang of 2.700 metres, establishing a finished overall length of approximately 8.000 metres. Chassis alterations are to be performed in accordance with Mercedes specification and an appropriate length Mercedes hand brake cable is to be utilised during the conversion.
After stretching the chassis is to be steam cleaned and paint finished in Mercedes grey prior to the body being attached. Paint finish will be two pack system with a gloss finish. Rust spots to the cab are to be shot blasted and primed at the same time. Wheels are to be shot blasted and painted; tyres will be removed before blasting. Tyres are to be refitted with new standard length valve stems (not the extended type) and balanced. Again paint finish as per Mercedes standard colour.
A heavy-duty hinged rear bumper is to be manufactured and fitted, again paint finished. The exact design is yet to be designed but will be of a substantial nature with appropriate towing/anchor eyes attached. Rear lights are to be the standard Mercedes fitment and are to be installed in such a way as not to be susceptible to damage. Side marker lights are also to be of the standard ‘square’ Mercedes type as fitted to the vehicle.
The fitted spare wheel carrier is to be maintained in the current position.
The standard Mercedes twin seat passenger chair is to be replaced with a right hand drive Mercedes Vario battery box and will be utilised as a general tool store area. We will fit to this a new single suspension seat to match the driver’s chair.
The original vehicle alternator of 55 Amps is to be retained. It is worth noting this is an upgraded unit from the standard fitment, which is 25 Amp and therefore should do the job required of it.
2. Skeleton frame
Currently we plan to fit a total of six Sietz double glazed S4 hinged windows, fitted with mosquito and sun blind. Each window will also to be fitted with an internal removable security grill mounted to the cabin in a robust manor. The removal and fitting system is to be easy to operate; final design is yet to be made
3.6 Roof hatches
Because of the need for roof hatches to remain watertight and secure it is proposed that the use of marine type deck hatches could be an appropriate solution. One hatch with an approximate size of 600mm x 600mm and one at 500mm x 500mm are required. The 600mm unit is to open 180 degrease to allow for access onto the roof from inside the cabin. All hatches will have secure locks and be able to be locked in a ‘ventilation’ position. Double glazed units are essential with smoked glass to keep down heat transfer.
Each hatch is to feature a mosquito and sunblind as well as the removable internal security grill. Secure fixing of the security grills will again be essential, the roof structure will be reinforced to ensure that grills cannot be forcible removed during an attacked with downward force. Again the removal and fitting system is to be easy to operate and will not protrude into the living area
4. Gas system
1 x 100 litre chassis mounted refillable gas tank fitted with:
Electronic level gauge (located on the main control panel) Second sight level gauge on the gas tank
The mounting brackets will be of a heavy-duty nature
1 x Heavy duty chassis mounting bracket to hold a 15Kg ‘Calor’ bottle or similar (non-refillable type) in the horizontal position and will be fitted out with:
Regulator valve and high pressure connecting hose
The mounting bracket is to incorporate a rubber seat for the tank to rest upon and an adjustable fixing system to secure the bottle so that various bottle sizes can be accommodated
Other components to include:
Manifold to gas appliances Second outlet point with isolation valve for external barbeque
Both the gas tanks are to located as high up the chassis as possible to maintain best ground clearance and are to be housed within a steel paint finished secure box. The tanks and boxes are to be secured in such away as not to come loose from the chassis when travelling on rough terrain and are to be reinforced at the base against potential damage from the vehicle grounding.
5.1 Fresh water storage and filtration system
The inlet filler pipe is to have an internal minimum diameter of 60mm and will be as short and direct to the storage tank as possible. The filling cap to be lockable and there will be a separate vent to aid filling. Vent and cap not to protrude past the line of the body, a large robust removable straining sieve with a maximum 250-micron mesh will be installed in the filler neck.
The tank is to be constructed from non-corrosive plastic and will be able to withstand the rigours of vehicle chassis flexing without leaking. Baffles are to be installed along with at least one 150mm inspection hatch for cleaning purposed. Manual drain slide valve of 100mm diameter with bayonet connection for a 4” flexible drain hose. Electronic water level indicator on the main control panel. Tank capacity to be a minimum of 700 litres
On the outlet of the tank after the 12-volt diaphragm pump will be a bank of three filters using common housings and mounting brackets. Connecting hose from the tank / pump / filters and couplings will have as large a bore size as practical. Filter performance will be:
1 x 60 micron washable 9 ¾ inch cartridge 1 x 20 micron disposable 9 ¾ inch cartridge 1 x 5 micron disposable 9 ¾ inch cartridge
G & S Services of Penrith, Cumbria, will supply these.
The kitchen washbasin will be fitted with a further separate Nature Pure water filter system complete with separate dispensing tap, unit distributed by General Ecology Europe Ltd.
5.2 Grey water tank
The storage tank capacity will be approximately 200 litres and will be of similar construction as the fresh water tank incorporating the same water level technology and 100mm slide valve for emptying. Two 150mm inspection hatches are to be incorporated for cleaning purposes. Slide valve is to be easy to access in operation, as is the bayonet hose connection and shall be protected against frost with 25mm of insulation. Tank shall also be insulated with a minimum of 25mm of insulation. Tank will be installed in-between the chassis rails just in front of the rear axel
5.3 Black water tank
The storage tank capacity will be approximately 200 litres and will be of similar construction as the fresh water tank incorporating the same water level technology and 100mm slide valve for emptying. Two 150mm inspection hatches are to be incorporated for cleaning purposes. Slide valve is to be easy to access in operation, as is the bayonet hose connection and will be protected against frost in a similar manor as above
5.4 Plumbing
In the interest of efficiency of the system and conservation of space, it would be good practise to keep the whole of the water system compact and if possible confined to a ‘wet room’ located in the garage area. The wet room will have an appropriate drain with plug in the event of a water leak.
All wastewater plumbing will be well-supported, accessible, high quality flexible pipe with a smooth bore to help avoid the build up of bacteria. The number of joints shall be kept to a minimum and where possible joints will be made using ‘Jubilee’ stainless steel worm drive and brass connectors. Domestic type basin traps to be used on the shower base and sinks to help prevent bad odours from the waste storage tank.
All delivery pipe work will be of a food grade quality and again be installed in the same manner as the waste water pipe: supported, accessible and of a high quality. Pipe work used for the hot water feed from the calorifier will be of a type appropriate for temperatures of up to 80 degrees Celsius, the normal red 15mm food quality is not suitable and should not be used as it is only appropriate for up to 45 degrease Celsius. The now common domestic semi rigid plastic push fit system will be used for this application
The pressurised line is to include the fitment of a pre-pressurised accumulator tank with membrane for smooth and balanced operation.
All pipe work is to be installed in such a way as to self-drain if required to do so for winter storage. Additional taps and drains are to be incorporated where appropriate to accommodate this. All pipe work is to be insulated and secured with cable ties to the pipe.
The calorifier is to incorporate two coils and a 1 Kw immersion heater, be well insulated and to be fixed in a very secure manner so as not to brake loose or cause damage to joints / couplings/ hoses. Unit to feature pressure relief valve set at 3 bar with dump to ground.
The marine units made by Newark Copper Cylinder Co Ltd should be explored as a possible calorifier supplier as they appear to build bespoke units at a reasonable cost.
6. Heating and hot water
Three energy sources are to be used to provide cabin heating, these are:
Diesel via a stand-alone blown air system producing approximately 4 kW of heat. The system will be able to heat both the under floor / garage area and the living area simultaneously or only the living area as required. To do this an appropriate valve will be required in the distribution hose to prevent the air entering the garage/ under floor area Diesel via the vehicles engine. Excess heated water shall be diverted through pipe work to the calorifier and radiators. Heat dissipation will be assisted with the installation of small 12-volt fans located behind radiator boxes. Gas water heater to feed calorifier Blown warm air from Dometic air conditioning system – 240 volt
Three energy sources for hot water:
· Diesel from the vehicle engine water system
· Gas water heater to feed the calorifier
· 240 volt immersion heater in the calorifier
Energy sources:
4 x Lucas AGM 12 volt, 160 Amp hour batteries 4 x 130 watt Kyocera solar panels with control system 1 x 55 amp / 28 volt DC vehicle alternator 1 x Electric start air cooled diesel operated generator with remote control start / stop / monitoring panel Model Pramac P4500 1 x Air-cooled petrol Honda 1.0 KV generator. 1 x 240 volt / 50 Hz land line connection – 8 amp maximum 1 x 110 volt / 60 Hz land line connection – 8 amp maximum
Energy systems:
Control panel, located inside the cabin Battery power monitoring system Earth leakage protection system Manual power source change over switch to protect generator and control systems Automatic voltage regulator Power converter, 110 volt @60Hz to 240 volt 240 volt operated multi step constant voltage automatic 12 Volt battery charger (pure DC) with built in cooling fan. Battery to battery charger, 24 volt – 12 volt Solar panel voltage regulator with power generation display True sine wave inverter, 12 volt DC to 240 volt AC with internal cooling fan. Approx 600 Watt continues output, minimum of 90% efficiency on load. Unit will be suitable for use with Lithium-ion battery chargers Separate power surge protector
Installed equipment:
240 volt ring main from inverter 12 volt DC lighting circuit using a combination of energy efficient florescent and LED lighting
12-volt water pump. Minimum flow rate 12 litres per minute at minimum 2 Bar pressure Fresh water tank level indicator (¼, ½, ¾, full) Grey water tank level indicator (¼, ½, ¾, full) Black water tank level indicator (¼, ½, ¾, full) Auxiliary diesel tank level indicator (¼, ½, ¾, full) Gas tank level indicator (¼, ½, ¾, full) Diesel operated water heater 240 volt immersion heater in calorifier Gas operated water heater Diesel operated blown air cabin heating system Blown air heating from vehicle cooling system Dometic 2200 air conditioning system Carbon Dioxide detector (Co2) Smoke detector (domestic type, battery operated) Living space cooling fans Low noise, low amp over bed fan 12 volt radio / CD player with 4 speakers ( located two front and two at the rear) Digital 17” TV with built in DVD player Coolmatic HDC220 compressor fridge / freezer Circulation fan for fridge / freezer cooler Circulation fan for garage mounted diesel generator Teleco 85cm automatic satellite dish 240 volt, 900 watt microwave oven Zanussi front loading mini washing machine 240 volt, 50Hz land line connection point. 16 amp blue socket 110 volt, 60Hz land line connection point, 16 amp yellow socket
8. Garage
Located in the garage will be:
Hot water outlet tap terminated with a ’washing machine’ type isolator valve (3/4 BSP male thread) Cold water outlet tap terminated with a ’washing machine’ type isolator valve (3/4 BSP male thread) Shower mixer valve complete with flexible domestic type hose (long) and showerhead. Isolator valve on both the hot and cold water lines feeding the mixer valve. 4 x Lucas 12 volt batteries Automatic battery charger Diesel generator complete Inverter (12 volt DC to 240 volt AC) Securing system for two spare wheels with tyres Wet room incorporating the water filtering system, calorifier and water pump 12 volt florescent light (s) with wall mounted on/off switch 12-volt air circulation fan for generator. Start/stop switch to be located on the main control panel in the cabin
9. Under floor storage
Fitted in the storage area will be:
12 volt florescent lights with wall mounted on/off switch Fresh water tank, see 5.1 Black water tank, see 5.3
10. Living space – general
Floor covering is to be a one-piece durable wood affect Linoleum. The bathroom floor surface is to wrap up and underneath the wall waterproof surface to create a sump affect that will ensure any splashed water from the sink or shower will be contained and cannot penetrate the fabric of the cabin.
The cabinets are to be finished in a light coloured beach wood affect and are to have all the mating surfaces glued as well as screwed together on assembly. When installing into the cabin, cabinets will be fixed to the cabin walls with Sikaflex adhesive to add strength and rigidity to the construction and to prevent direct contact of wood with the walls. Door furniture, light fittings etc are will be finished in chrome affect
For ease of description I have divided the living space into five separate areas: Lounge, Kitchen, Wardrobes, Shower room and Bedroom.
Seating area as per plan to convert into a full sized double bed. Cushion covering will be fabric and washable High level storage lockers 12 volt florescent lighting to centre Hidden 12 LED lighting to the bottom of the overhead storage lockers Various 240 volt sockets from inverter Various 240 volt sockets from mains/generator supply 2 x 12 volt fans, multi speed with adjustable position Curtains to three sides with pelmet and curtain ties
10.2 Kitchen
Features will include:
Oven with four gas burners and large gas oven / grill. Unit to feature electronic ignition Stainless steel sink with one and a half bowls fitted with domestic type waste water u-bend Separate domestic type mixer tap Hidden 12 volt LED lighting to the bottom of the overhead storage lockers Extractor unit over oven with light Zanussi washing machine as listed above and securely fastened 12 volt TV and DVD player mounted above washing machine Coolmatic compressor fridge freezer fitted with an additional 25 mm of insulation to top, bottom and sides. Domestic microwave oven with turntable fitted over washing machine Control / switch panel over door Full height larder cupboard
10.3 Wardrobes
10.5 Bedroom
Features will include:
Curtains and pelmet to windows. Ventilated wooden lated base for mattress Overhead low noise, low amp fan Two speakers from the radio/cd player in lounge 12 volt overhead florescent light Two 12 volt LED reading lights on flexible stalks Curtain to separate the bedroom from dressing area. 240 volt sockets from inverter at top and bottom of bed
11. Outside
Automatic 85 cm self seeking satellite dish and receiver Manual awning 5.5 metres long Flush fitting florescent light near or over main door At the rear two 12-volt work lights mounted high on the body with switch in the cabin. Swivel type, 50 watt Steps to cabin with appropriate secure fixing Aluminium diesel tank located in-between the chassis rails at the rear of the chassis. Baffles are to be installed along with at least one 150mm inspection hatch for cleaning purposed. Electronic fuel level indicator on the main control panel. Tank capacity to be a minimum of 200 litres with the inlet filler pipe is to have an internal minimum diameter of 60mm and is to be as short and direct to the storage tank as possible. The filling cap is to be lockable and there should be a separate vent to aid filling. Vent and cap should not protrude past the line of the body. A large, robust, removable straining sieve with a maximum 50-micron mesh should be installed in the filler neck. Two outlet points both fitted with hand operated gate valve. The first outlet should be fitted with a flexible fuel resistant hose to be used for the topping up of the standard truck fuel tank. The second outlet is to incorporate a fuel filter / water trap and to be used to supply diesel to the associated diesel operated systems by dedicated fuel lines and valves