By Ian A., Trade Connectors
Yes, you can fit a dedicated external Anderson connector point on your campervan, and if you run a portable solar panel or want an outside 12V input, it's usually a better solution than opening the leisure battery locker every time you park up. The short version: use a genuine SB50 chassis-mount (panel-mount) housing sited somewhere low and sheltered — under the skirt or on a chassis rail, not on a flat vertical panel — run a short, correctly-sized flylead back to your controller or distribution point, and get two things right that UK self-converters routinely get wrong. First, colour: Anderson housings are physically keyed, so a grey plug won't mate with a red socket — it isn't a cosmetic choice, and (with one documented exception on SB50, covered below) buying the wrong colour means buying again. Second, weatherproofing: an open-faced connector mounted on the outside of the van will let water in eventually unless you deal with both the cable entry point and the exposed socket face when it's unplugged. Get the housing, the colour and the seal right from the start and it's a genuinely solid, serviceable fitting. Get any one of them wrong and you'll be doing it twice.
Why fit an external connection point at all
The usual driver is a portable solar panel. More people are self-converting vans and running a portable panel they can angle towards the sun or move into shade, rather than (or alongside) fixed roof panels — and the practical problem is getting the panel's cable to the charge controller without drilling a new hole in the van or opening the battery locker door every time the panel goes out. An external Anderson socket, wired straight through to the controller, solves that: the panel plugs in from outside, the controller and battery stay sealed inside, and the same socket doubles as a general external 12V input if you ever need one — for topping up from another vehicle, or powering something like a satellite internet terminal without running a cable through a window or door seal.
It's a small job, but it's also an exposed one: everything about it sits on the outside of the van, in the weather, for years. That's why the detail matters more here than on an internal connection.
Choosing and siting the housing
You want a panel-mount (also called chassis-mount) SB50 housing — a version of the standard Anderson housing designed to bolt through a flat surface, as opposed to the familiar loose cable-to-cable housing. Stick to a genuine Anderson Power Products housing rather than a cheap import copy for this particular fitting more than most: a panel-mount housing has a mounting flange and, usually, a spring-loaded dust flap, and that's exactly where a loosely-moulded import copy tends to sit slightly proud or fail to close flush — which is precisely where water gets in. The same genuine-vs-import difference in plating and housing tolerance that affects crimp reliability on a cable-to-cable joint matters even more on a fitting that's bolted outside and rained on.
Siting matters as much as the housing itself:
- Mount it low and under something — the skirt, a chassis rail, the underside of a step — rather than on a vertical body panel where rain runs straight down the face of the connector.
- Angle the housing downward slightly if you can, so water sheds off the flap rather than pooling on it.
- Keep it away from wheel-spray paths and low enough that it isn't catching horizontal rain in a crosswind, but high enough it isn't sitting in standing water or road grit.
Getting the colour right
This is the detail most self-converters get wrong, because it looks cosmetic and isn't. Anderson SB50 housings are physically keyed by colour: the plastic shape of a grey housing is cut differently to a red one, so a grey plug simply will not push into a red socket. It isn't a labelling convention you can ignore — it's a mechanical fact of the housing design.
There is one documented exception: on the SB50 size, black and grey housings are keyed to mate with each other. Every other colour pairing — red, blue, orange, yellow, green — only mates with itself. So if the connector already fitted inside your van (on the leisure battery, or an existing panel) is grey, your new external point needs to be grey or black, not red or blue, or the two halves won't physically join.
There's no universal published standard dictating what each colour has to represent — grey for general 12V power and red for solar is a common convention among installers, not an industry rule, so you're free to set your own scheme. What matters is consistency: pick a colour per circuit and stick to it across the van, so you (or whoever works on it after you) can tell circuits apart at a glance without digging out a multimeter.
On sizing: SB50 is the standard choice for a single portable panel feeding a 12V leisure system, comfortably rated above the current a typical panel and controller combination draws. If you're running something unusually high-current through the same external point, it's worth checking that SB50's rating actually covers your setup before you commit to it.
Weatherproofing it properly
Fitting the right housing in the right place still leaves two weak points to close off:
The cable entry. Where the flylead passes through the skirt or bodywork, use a proper grommet and seal the gap — don't leave a bare cable run through an unsealed hole. Leave a drip loop in the cable before it reaches the housing, so any water running down the cable drips off at the lowest point rather than tracking straight into the connector.
The open face. This is the one people forget. When nothing's plugged in, an open Anderson socket facing downward and outward is still an open socket — a spring-loaded flap cover (sold as an accessory for genuine Anderson panel-mount housings) or a simple push-in dust cap keeps rain and road spray out when the panel isn't connected, which on a van used three seasons out of four is most of the time.
Fully sealed, marine-certified connector enclosures exist — the kind sold through chandlery suppliers for boats — at a real price premium over a standard Anderson fitting. They're worth knowing about if you want marine-grade certification specifically, but for a van conversion, a genuine Anderson panel-mount housing, sited under cover, with a flap cover and a sealed cable entry, is the proven, practical standard most UK self-converters actually use.
Wiring it in
Run a flylead sized to the actual length of the run, not just matched to the panel's own cable gauge — a long thin run drops voltage further than a short one at the same current. Crimp it properly with lugs and a ratchet crimper rather than twisting or soldering the joint (soldered joints go brittle and crack under vibration, which matters on a vehicle), push the lugs fully home until they click, and double-check polarity before you close anything up. Get the orientation consistent on every lead in the van so the wires don't twist when you connect and disconnect repeatedly.
Common mistakes to avoid
- Assuming any colour will do. It won't — buy the colour that matches what's already fitted, or the new housing physically won't mate with it.
- Leaving the open face uncapped. An unused external socket left bare to the weather is the single most common cause of corrosion inside an otherwise well-fitted connector.
- Using a cheap import panel-mount housing to save a few pounds. The flange fit and flap seal are exactly where the savings show up, in the form of water ingress a year or two down the line.
- Mounting on a vertical, exposed face instead of somewhere sheltered and angled downward.
Browse our genuine Anderson cables and housings for campervan and solar setups in the Leisure & Solar collection.
FAQs
Can I fit an Anderson connector to the outside of my campervan?
Yes — genuine SB50 chassis-mount (panel-mount) housings are designed for exactly this, as long as you site it somewhere sheltered, such as under the skirt or on a chassis rail, and weatherproof both the cable entry and the open face when nothing's plugged in.
Do Anderson connector colours actually matter, or is it just cosmetic?
They matter. SB50 housings are physically keyed by colour, so — with one exception covered below — a given colour will only mate with the same colour. It isn't a labelling choice; mismatched colours simply won't push together.
Are black and grey Anderson SB50 connectors interchangeable?
Yes. On the SB50 size, black and grey housings are keyed to mate with each other — the one documented exception to the same-colour-only rule. Every other colour pairing (red, blue, orange, yellow, green) only mates with itself.
What size Anderson connector do I need for a portable solar panel?
SB50 (50A) is the standard choice for a single portable panel feeding a 12V leisure battery system, comfortably rated above the current a typical panel and controller combination draws. If your setup carries unusually high current, check SB50's rating actually covers it before fitting one.
How do I stop water getting into an external Anderson connector?
Cover the open face with a spring-flap cover or dust cap when nothing's plugged in, seal the cable entry point where it passes through the bodywork or skirt with a proper grommet, and leave a drip loop in the cable so water sheds off before it reaches the housing.
Can I use an Anderson connector instead of MC4 for a portable solar panel?
Many self-converters do, mainly because Anderson connectors are built for repeated plugging and unplugging, where MC4 connectors are designed to be connected once and left in place. For a panel you take on and off regularly, that durability is the main advantage. MC4 remains the standard for panels permanently wired to the roof.