D4 12V options

[dunnymel]

Opinions, comments requested please folks.

I'm mulling the best 12v power system for my situation. I have a 2012 D4 and new 2nd hand camp trailer (2003 trakshak). Power requirements quite simple; just an old Engel in the back of the car and a couple of camping lights off the trailer. Upcoming 3 week long distance road trip with 1-2 night camps only,
The D4 is currently completely untouched re after market stuff, and hoping to keep to a minimum.
The trailer has a deep cycle mounted up front and a 7 pin plug for charging it.
Not sure what plugging it straight into the mysterious D4 white plug will do (opinions seem to vary on other threads).
I assume it will charge the battery but what happens when ignition off ? (ie is the cranking battery protected from being drained while camping, or can it be modified to do this?).

I am thinking to run a custom made long fridge cord from the auxiliary battery on the trailer, up the drawbar and under the tailgate seal into the car to run the fridge (this seems to work ok without squashing the cord).
On face value this seems potentially a simple option that may mean I can avoid an expensive battery management system?

Thoughts?

Thanks
Andrew

[gghaggis]

There are many threads on this, and you're right - it can get confusing. Does the trailer have a fridge, and can that be 12v powered directly (ie not via the trailer battery). I'd assume that's why you want power to the trailer whilst driving, or is it only to trickle-charge the trailer battery? Or both?

You'll need to work out exactly what you're trying to achieve before you design the charging system.

Cheers,

Gordon