Motorhome Campervan & Leisure Vehicle Autoelectrical in Shropshire & Mid Wales

We provide a full range of services and parts for Motorhome and Camper van users including :
Autoelectrical fault tracing
Wiring of additional lights
Split Charge Auxilliary Battery for onboard power
Assistance with vehicle conversions

Electrical power generation equipment for motorhomes and camper vans



The Alternator functions as a generator to charge both the vehicle engine battery and auxlliiary leisure battery systems.
We supply of a wide range of motorhome alternators and alternator repair parts to suit your motohome requirement.

On holiday and broken down ? Callout service available for motorhome alternator fitting in Shrewsbury Shropshire and local.


Power inverters are fitted to motorhomes to step up voltage & convert input power from the 12 volt (12v) dc battery to 240v alternating current (ac) mains type output for supply of domestic accessory equipment which normally operates at house domestic mains voltage. Selection of a suitable inverter specification introduces many factors related to power supply capability of vehicle batteries, charging system, cabling, and intended periods of use.


Additional On board or Stand alone site generators can be used to provide electrical power supply for the motorhome. Low noise versions should be considered.

Motorhome Leisure Battery Charging

Motorhome Battery Banks

It is important to keep motorhome leisure battery banks charged and in good order.

Additional auxiliary leisure batteries may be used as an off-grid power supply for both

  • 12v equipment such as interior and exterior lights, 12v refrigerator, 12v tv, 12v domestic water pump
  • power an inverter to supply 240v equipment including 240v lighting, television, microwave, laptop,
  • when the motorhome or camper van is parked.

    Vehicle capacity, circuit load, and intended usage will determine the requirement for leisure battery bank capacity

    Parallel Battery Operation

    Starter battery and auxilliary battery are connected with heavy duty cabling via a battery isolator switch, which when turned on allows the auxilliary battery to link to the starter battery to provide extra power to the starter motor allowing cold starting assistance.

    Battery charging via 240v Hookup

    A Hookup cable connects mains site power (240v a.c) to the motorhome 'blue plug' 16A (BS4343) connector. The 240v AC mains input provides power supply to a multi-stage battery charger with DC output around 13 volts connected to 12v leisure battery bank. Failure of the battery, battery charger, or wiring may cause low leisure battery voltage. The leisure battery voltage may be indicated on a panel gauge inside the motorhome or can be checked using a multimeter.

    Split Charge Ancillary Battery Systems

    The basic motorhome split charge system will charge batteries whilst the vehicle engine is running using power generated by the vehicle alternator.
    Auxiliary leisure battery banks are recharged by the engine driven alternator via wiring possibly direct to the back of the alternator to a second B+ terminal, or from a convenient point such as the engine starter battery terminals via either switchgear or a dc-dc battery charger.

    Voltage Sensitive Relay (VSR) Split Charging System

    Vehicle starter battery (1) is linked to the auxilliary battery bank (2) via an automatic solenoid switch or voltage sensitive relay (VSR).
    When the engine is off (stationary), the VSR disconnects the second battery to prevent current draw from the auxilliary battery.
    Firstly, this ensures the engine starter battery retains enough power to start the engine after periods when the motorhome domestic equipment such as lights have been used.
    Secondly, because the wiring system between engine starter battery and secondary batteries often uses smaller cable than the heavy cable used between engine starter battery and starter motor, disconnection of the leisure battery protects auxilliary cabling from overload.

    After the engine starts and the alternator starts to charge, a rise in starter battery voltage is detected, VSR switch contacts close allowing electrical charging current to flow from the vehicle alternator to the auxilliary battery. VSR units available in 12v and 24v versions
    VSR part nos
    HC161059 (12v 160A) HC161060 (24v 160A) HC161955 (dual version 12v or 24v 140A)
    HC161128 (12v 200A)

    DC-DC battery to battery charger

    A more advanced method of recharging leisure battery banks with a split charge system involves use of a DC battery to DC battery charger to regulate charging current. DC-DC chargers vary in specification, some with programmable features to enable recharge of specialist battery systems.

    Auxilliary battery charging system using blocking diode

    A diode acts like an electrical non return valve. Battery charging current is allowed to pass from the vehicle alternator to the auxiliary leisure battery only.
    The blocking diode prevents reverse current flowing back from the auxiliary battery to the starter battery during engine start.

    Solar Panel Leisure Battery Charging System

    solar panel

    Additional battery charging can be provided by fitting a solar panel battery recharge system.
    Solar panel systems usually require an additional (MPPT) voltage regulator charge controller.
    More information can be found on our solar panel web page

    Modular Electrical System


    Modular electrical systems such as those by Electroblock and Sargent are fitted to many motorhomes incorporating several circuit functions in to one electronic unit including:

  • Interior lighting
  • 12v Battery charging
  • Water pump for sink & shower
  • Fridge electrics
  • Power supply for 12v water heater
  • Power supply for blown air heating system
  • Power supply to inverter
  • Power supply to 12v sockets
  • The modular charging and distribution board may be remotely switched from a seperate switch control panel.

    Battery Guard

    Battery guard equipment can be fitted to ensure vehicle batteries stay above a preset voltage level by providing automatic battery disconnection. Battery guards are particularly useful when vehicles are being put in to short term storage.

    Starter Motors for Motorhome engines

    Supply of a range of starter motors to fit Diesel and Petrol engines in motorhomes and campervans based on
    Ford Transit
    Fiat Ducato
    Mercedes Sprinter & Vito
    Renault Master
    Vauxhall Vivaro
    Volkswagen Transporter, T2, T4, T5, T6, Crafter
    Autotrail, Adria, Hymer, Swift leisure vehicles.

    Motorhome and Camper Van Climate Control

    Night heaters


    We have night heater diagnostic equipment for various makes of motorhome and campervan (nightheater) blown air heating systems including Eberspacher Airtronic and Webasto Airtop 2000 and may also be able to assist we sourcing components. We do not repair the cheap chinese diesel heaters.

    Low auxiliary battery voltage can cause faults with a nightheater preventing operation.

    Motorhome Air Conditioning and Cooling

    A range of air conditioning equipment is available for motorhomes and leisure vehicles including factory fit using engine driven air conditioning systems or standalone roofmount air conditioner units.

    FGAS qualified engineer providing a range of motorhome air conditioning services including air conditioning test, repairs and regas.

    Motorhome Computerised Diagnostics

    Many motorhomes are built on a converted van chassis. Our Specialist computerised diagnostic equipment is capable of vehicle computer modules on many motorhome and camper van electronic systems including engine management, airbag, and antilock braking systems *subject to specific software compatability.
    More information can be found on our vehicle diagnostics web page

    Audible Reverse Warning Systems

    Reversing warning bleeper Installation

    Motorhome MOT preparation

    Despite vehicle size, many motorhomes and motor caravans fall under the class 4 MoT test group which is the same category as for passenger cars.
    The MoT test centre must be able to accommodate the size and type of vehicle with regard to workshop space, equipment and qualification.

    A full list of items to be checked can be found in the relevant DVSA MoT testers manual downloadable from the .Gov website.
    Key points are condition and security of components affecting vehicle safety including
    Drivers controls and vision including windscreen, wipers and washers

    Obligatory lights

    including sidelights, tail lights, no. plate lamps, marker lamps, dip and main beam headlights, stop lamps, direction indicators, hazard warning, reverse lamps depending on date of first use. The wiring to motorhome lights may be difficult to access due to the first and second fix construction techniques involved in motorhome body building.


    including parking brake (handbrake and cables) and service brake (footbrake) condition and operation, hydraulic systems, master cylinder, brake pipes, wheel cylinders and brake calipers, brake friction linings (barke pads and brake shoes)


    Security, condition, operation of steering wheel, steering column, couplings, power steering, steering rack, track rods and track rod ends, kingpins and stub axles.

    Body and chassis components

    Wheels and tyres

    Condition, Correct size and type of tyres, tread depth (1.6mm min), presence and security of wheel nuts, wheel bearing condition.


    Condition of body panels and bumpers for security and sharp edges. Operation of doors and door locks.

    Motorhome Habitation Inspection

    A habitation check is a seperate inspection which is not currently part of the vehicle MoT test.
    Habitation inspection checks include observation of condition of equipment linked to the living quarters of the vehicle including electrical and liquid petroleum gas (LPG) equipment.

    Autoelectrical engineers get involved with fault tracing and repairs of certain 12v & 24v equipment.

    Van Conversions - a few notes

    Some people self-convert a standard panel van in to a camper van by adding features such as
    Insulation materials - possibly earthwool fitted between interior and exterior body panels.
    LED interior lighting with low power consumption
    240v mains hook up point via 16 Amp supply, with Residual current device (RCD)
    240v to 12v battery charger
    Auxilliary battery
    Split charge system - battery to battery charger , voltage sensitive relay (VSR) , battery isolation switch.
    12 volt power distribution board with fuses or circuit breakers.
    12v to 240v Inverter
    Night heater
    Wood burning stove (- one of our plumber customers has fitted a compact wood burning stove in his camper van )
    Sink with 12 volt water pump
    Gas Cooker
    Gas bottle storage compartment
    Cool box
    Fridge - 3 way fridge which may be run on gas, 12v electric, or mains. Requires ventilation.
    Interior storage cupboards
    Side Awning
    Reversing camera kit
    Mobile Digital Video Recording (DVR) system.
    WiFi systems for mobile internet
    Television & Satellite system
    USB sockets
    Seperate roof mount air conditioning unit
    Additional exterior lighting
    Elevating roof conversion kits
    Roof racks
    Access ladders
    Security locks
    Rodent deterrant - Rodents can be problematic to motorhomes. We have come across several vehicles where rodents have chewed through pvc insulation and wiring cables.

    A good recommendation is to carefully plan any proposed van conversion. Electrical wiring is often carried out in stages during a vehicle build. First fix installation may require running cabling before panelling is fitted. While second fix involves connection of equipment. Third stage can involve inspection & certification as required.

    Specially designed cabinet kits are available for specific vehicles.

    Some additional Important Safety Features for camper vans and motorhomes

    Battery Isolator Switch
    Electrical circuit breakers, fuses, and rcd
    Smoke Alarm - we always recommend fitment of smoke and Carbon monoxide detector alarms in camper vans, motorhomes, and ambulances
    Fire extinguisher
    First Aid Kit
    Check operation of all entrance doors and exits.
    Check adequate ventilation.

    Motorhome Camping in Shropshire & Mid Wales

    Shropshire & Mid Wales has a wide range of short stay camping facilities,