Quote:
Originally Posted by Ian21401
Is the need for the 12S socket because your caravan has two 7 pin plugs?
As your car already has a 12N socket there is no need to replace it with a 13 pin socket.
Whilst a 13 pin socket could be fitted to the existing wiring on your car it would not give any advantage as the split charge relay and associated wiring is almost certainly not fitted to your car
If you plug the caravan 12N plug into your existing 12N socket you should still have all your caravan running lights so you would still be legal on the road but the caravan reverse lights ( if fitted) would not work.
The 12S socket and plug were introduced to enable feeds to the caravan domestic circuits (lights etc.), fridge, battery and caravan reverse lights. Simple connections from the car’s wiring to the caravan’s domestic circuits and reverse lights and earth are all that is necessary for those. BUT
A “Split Charge Relay” device is required in the car’s electrical feed which is connected to the caravan fridge and battery supply. The purpose of this is so that when the car’s engine is running, and hence the alternator is charging, there is a current being fed to the caravan’s fridge and onboard battery but when the car’s engine is not running and there is no charge from the alternator then the caravan fridge and battery are disconnected and are not flattening the car’s battery. ( the charge from the car’s alternator is being “split” between the car’s battery and the caravan. This is only live when the current from the car’s alternator activates a “relay” within the device to connect the circuits. Hence the name “split charge relay” )
You could wire the 12s socket so only the caravan’s domestic circuits (pin 4. green ) and reverse lights (pin 1. yellow ) and earth ( pin 3. white) were actually connected leaving the fridge ( pin 6. red) and battery ( pin 2. blue ) with no connection. This would mean that they would not draw power from the car’s battery but they would not be running whilst you were towing. If you do not intend to tow for a long trip and the fridge was properly cold before you set out then it would be OK until you stopped and switched the fridge to EHU or gas when sited. Your caravan battery would not charge either during your travel but would be OK once connected to EHU on site. However, if you were not connecting to EHU then the fridge would have to be run on gas and the caravan battery would eventually go flat.
I hope this helps.
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Yes makes sense.
I tow a caravan on a semi regular basis. I need the facility to cool the fridge and charge the leisure battery from the car.
I'm not fussed on either a 13pin arrangement or a dual 12s/12n arrangement, I just need those facilities.
If I purchase a kit with a split charge relay (seems available in ebay and the like) will that be feasible to wire up?