T5 Camper Van Electrics

Space is at a premium when turning a modest sized van such as a Volkswagon T5 into a camper van. The obvious solutions are not necessarily the best or most aesthetically pleasing.

For the low voltage services such as the refrigerator, cabin lights and water pump it’s not sensible to rely upon the automotive 12 Volt battery, it will deplete the charge too much. So an additional leisure battery is required to supplement the power available. The additional leisure battery and the ancillary circuits it feeds need to be kept separate from the original power circuits, this is achieved by using an electronic split-charge-relay. The split-charge-relay only connects the automotive power to the leisure battery when the alternator is producing more than 13.6V. This allows the leisure battery to charge whilst the vehicle is running, but prevents the use of the automotive battery power at other times. It also prevents the heavy current demands of the starter motor from impacting the leisure battery, which is not designed for that kind of service.

There are a number of options for locating the leisure battery. My choice was to house it under the driver’s seat, rather than taking up space in the rear cabinets (space is at a premium there). For this you have to select a suitably size battery. I chose a Powerline Leisure XV190 battery which is low enough to fit. The battery is secured to a bracket in the base of the seat-box using a pair of heavy duty luggage straps to ensure that it is held firmly.

In addition to having low voltage circuits, it is also useful to add a mains power hookup to have 13A sockets available in the rear cabin. For this we need circuit protection, an RCD to protect the users and over-current protection for the cabling. It is important to use suitable impact resistant fire retardant mains cabling to connect up to the sockets, ordinary PVC flex or even twin and earth cabling is not really suitable. The mains feed also gives the option of installing a mains powered battery charger for when on site for more than a couple of days (that’s something I’ll add later).

From my research there appear to be a number of options as to where the mains hook-up connection can be fitted on a T5. Each has their own pro’s and cons:

  • A power hookup connector cut into the side of the van – looks ugly
  • A 16A connector on the underside of the rear behind the rear bumper – likely to get very dirty and corroded
  • Concealed behind the rear quarter panel – only suitable for tailgate models, quite a lot of fiddly work to add the hinges to the panel and might damage paintwork
  • Under the bonnet in the battery compartment – confined space – have to open bonnet to plug in

I went for the last option and worked carefully around the space issue. 

Most camper conversions I’ve seen, approach electrical circuit protection by installing a small consumer unit. There are three downsides to that approach:

  • They are not small, its an ugly metal box with a DIN rail, bus bar, RCD module and circuit breaker. You have to find the space to fit one (and space is at a premium) , it also has to be accessible so that you can reset the RCD or circuit breaker.
  • When you’ve found a space to fit it, that may not be close enough to the power inlet connector (it should be as close as possible since its there to protect the power cables in van), so its difficult to find a suitable place.
  • They are expensive overkill for the job in hand. You are only needing to protect a single circuit and are unlikely to consume more than 13A, at best the hookup is going to supply 16A.

I chose to use a metal clad RCD 13A spur instead of a consumer unit. At £15 rather than £70+ it seemed like a good idea, more importantly it is only 75mm square, so will fit into the limited space in the battery compartment under the bonnet. I built a connection board that fixed to the plastic bulkhead connecting the 16A fixed plug directly to the RCD. The hookup module is fixed to the rear plate (shown with all 3 parts temporarily assembled before being installed). This arrangement protects the circuit as close to the inlet as possible ensuring that there is no unprotected 240V cable in the vehicle. 

Once installed the hookup cable fits below the closed bonnet with enough clearance for the cable when closed. The bonnet can be locked down when the cable is connected, preventing unauthorised removal if the vehicle is left unattended.

Whilst having the cab stripped out to install the cables across the cabin floor, I took the opportunity to add more sound deadening. This has made a significant reduction in cabin noise.

Both the 240V cable and the split-charge-relay feed cable have to pass through the shield behind the battery and the bulkhead into the cabin. Ensure that the holes have rubber grommets and abrasion protection where the cables pass through.  The cables can then be routed across the floor of the cabin, under the centre console cover and routed along side the existing cables, to beneath the driver’s seat, where the leisure battery and first power outlet are located.

The little 6 way fuse box for the 12V ancillary circuits is housed at the front of the seat base adjacent to the split-charge-relay module where it can be readily accessed if required. To keep things in the rear clean and tidy the electrical panel is installed into the rear seat base cover. This is a great way to fit the electrical panel as it can be easily unclipped for maintenance or further additions.  A double socket at the rear of the worktop is wired in series with the single socket on the electrical panel again using the high spec cable.

There seem to be as many approaches to T5 camper van home conversions as there are people carrying them out. My approach is to leave the outside of the van as unmodified as possible whilst trying to provide all the facilities required. One thing is for sure no one home conversion van is the same as another.

2 thoughts on “T5 Camper Van Electrics

  1. Just curious, if your 240v live made contact with the metal of your van, eg. wearing through the cable due to vibration over time, how would your RCD solution trip?

    • Good point: The earth from the incoming feed being connected to the bodywork of the Van would Trip the RCD if that happened. I omitted to mention that in the post, well caught. For the RCD protection to work does require that the hookup has an adequate earth, so it means always using the test button on the RCD whenever you hookup, if the test fails you shouldn’t use the hookup. The whole connection of 240V to mobile vehicles is a bit fraught, I’m considering including a Martindale check plug in the van equipment to ensure that the supply has been wired correctly. Also standard PVC flex should not be used. I did consider using pyro, but that has challenges with moisture absorption in the terminations and is awkward to retrofit into a vehicle, the cable I’m using has an earthed metal shield around the conductors beneath the outer non PVC sheath.

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