Thread: Trailer anderson plug connector on MY15 Defender

There is a factory fitted live wire that is up behind your tail lights , I has a 10amp fuse that is under the drivers seat . I would use that for something else . Run a new wire back to your battery put a fuse in the battery box . then you know where it is . Use plenty of cable ties !!..Jim

I'd put an isolation switch on it.
A few years ago at Fraser I came back to my d2 to find a guy pumping up his tyres off my Anderson plug at the back. Needless to say now everything on the external on my car has some sort of isolation on them.

Originally Posted by Dorian

I'd put an isolation switch on it.
A few years ago at Fraser I came back to my d2 to find a guy pumping up his tyres off my Anderson plug at the back. Needless to say now everything on the external on my car has some sort of isolation on them.

That must have been an interesting discussion

They call them "bush power points"






If I were you, mr OP, I'd do it like this. Your results may vary if we are talking about a 110.


1) Get rid of the crap battery terminals that are stock on the defender. they are just going to cause you grief. Get something like this:


2) Run a short line from the battery terminal to a 70A switchable, resettable circuit breaker. This will allow you to turn the anderson plug 'off' if you want. Get creative with its location if you don't want to pull the passenger seat apart to turn on / off the anderson power socket. This would be super skookum:

The above pic is a surface mount CB, but You can also get a panel mount style, so you could mount the switch on the door-facing section of the battery box, and have the cables inside. That would be sweet.

3) Work off a 4 meter cable length to the back of the plug and return, and get some 5 gauge cable (16mm2 cross sectional conductor area). Ideally grab the twin core stuff that is in a sheath with a red and black wire. This will be easiest to route. This cable size should give you a very low voltage drop (0.6V) to the plug, which will only get worse by the time it gets to the trailer).

4) Drill a hole into the rear of the battery box, then get a grommet or cable gland or just wing it (no... don't) to protect the cable. From there, route to the inside of the chassis rail, and zip tie to the existing cable loom. Use some split conduit if you want bonus neat points.

5) When you get to the back of the vehicle, you'll end up in the LHS wheel well. You can run the cable thru the rear of the vehicle above the crossmember to line up with the trailer hitch plug loom, or just forge your own path to where the plug needs to go. Secure the anderson plug, and use one of those rubber caps to keep the electrical pixies where they belong.


Not sure what loads you are expecting in the trailer, but the 50A 'anderson' plug is rated for 50A continuous, and max 75A, IIRC. By my understanding this might be encroached upon if you are charging, or sharing a large electrical load between multiple battery banks (a winch, large inverter etc).
The terminals for the 50A anderson plug may be a tight fit with the 5 gauge cable, but it seems that people run the 50A anderson plugs irrespective of the loads they are wanting to draw thru it! Blasphemy!


It's a simple job, hardest part will be drilling the hole in your new car!
(Or throwing money at your auto electrician)

Nice write up thanks! ... I need to install one too :>)

Originally Posted by YOLO110

Nice write up thanks! ... I need to install one too :>)

In my hamfisted experience, the space between the battery box and door is very limited, and I would expect the above to be pinched.
Oops reread Toxics post, but measure twice cut once.

The biggest concern would be such a large hole in the seat box (structural / engineering issues?)

Blue sea part 7041:

Actual height it would sit proud of the panel would be 18.59mm

Just one of many ways to skin the cat though

Should be an existing hole in the rear of the battery box.

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