7 pin plug auxilliary wire to run van fridge while driving?

Short answer is yes the 7 pin plug pins aren't big enough to carry the amps your fridge will pull.

If you are using an anderson plug you can use it to supply your fridge providing your wiring is of a suitable size to carry the additional load imposed by the fridge.

Get some good advice from a 12 volt specialist before you do anything, most van manufacturers wire the 12 volt fridge supply to the 7 pin connectors, but they all overheat the pins when running the fridge.

By rights your anderson plug charges the c/van battery and your fridge runs off that battery does it not ?? Ergo just remember to unplug the anderson when stopped for any lenghth of time with motor switched off unless you have a dual battery cutout already installed.

Most 7 pin trailer plug and sockets are rated at 20amps constant load over all circuits so you could get away with it but you would be right on the limit and as said before you would properly melt the plug and socket.

You could change it over to a flat 12 pin socket and plug that has a higher current rating.

The ideal way would be through an 175amp Anderson plug and socket and a RedArc dual battery isolator connected inline with the fridge.

When your engine stops running the battery isolator will detect a voltage drop at 12.7 volts and disconnect the fridge.

If you have a battery in the caravan you can Tee of before the battery isolator (for the fridge) and charge the caravan battery without the fridge drawing from the battery.

It's also advisable to have a second battery isolator mounted to you vehicle that isolate the caravan from the vehicle.

And don't forget the fuses.

Check the wiring running to your anderson plug through to your caravan battery is heavy enough for the load of the fridge, if so leave the fridge in the van connected to the battery and charge the battery and run the fridge via the anderson plug.

I can't see any need for extra wiring, so long as the original anderson plug is wired up with heavy enough wiring, as well as the wiring running from the anderson plug to the battery in the van being heavy enough.

Con,

I have 2 heavy pairs of cables running from the front of the vehicle to the trailer. At the front, both of the positive lines are switched (independently) by 30A relays so that power is fed from the front to the trailer when the engine is running. I use Anderson plugs to connect between Troopy and trailer.

Why so many cables? One pair to charge the trailer battery, one pair to run the 3 way fridge. By keeping these independent, the high current drawn continuously by the fridge doesn't drop the battery charging voltage. (Even a fraction of a volt loss can substantially reduce the charging current.)

Why independent switching? To avoid the situation where the fridge would run off the trailer battery if the two positives were connected together.

This works well. I'd particularly recommend using solid connectors (Anderson) rather than relying on the 7 pin trailer connection. The earth return especially will be heavily loaded if it is called on to carry a few amps for lights, 10 or 12 amps for the fridge, maybe more than that to charge the battery.

HTH

John

You can also use a motion sensitive 'Fridge Switch' to isolate the fridge while the vehicle is stopped.
Rod

Hi Con
Take john & val's advise ,wire it seperately Say 6 b& cable POS & neg, back to the tug battery with an ignition controlled relay or voltage sensitive relay in the pos lead &also fused @ battery
/If you wire it of the van battery unless you use quite large cables pos &neg right thru from tug bat to van bat ,the van bat will be very unlikely to get a decent chargei

I have 12 pin plug and the fridge and van battery run though that with the ingnition on but are cut of once the engine is turned off.If stopped for a while just turn the gas on and light the fridge yours PK

An Anderson plug is not required for the auxiliary cable.
A Round 7 Pin Plug or Flat 12 Pin Plug plug will do the job as the Auxiliary cable pin is heavy Duty and will handle 20amps easily. The fridge will pull around 11amps. The cable size to the plug should be around 6B&S.
7 pin flat plugs won't do the job as the pins are to small and the auxiliary one will eventually burn out.
ozjohn.

Con,
You say: -> "and the anderson plug was to **charge the battery** while driving"
You obviously have a battery where the fridge is,
so direct wire the fridge to this battery via a "smart solenoid" and decent fuse and you will have NO hassles.

Maîneÿ . . .