Caravan (12S) Relays
Introduction: Caravan Fridges and Auxiliary Batteries.
Protecting the vehicle battery
When a vehicle tows a caravan and the caravan is equipped with a 12 volt fridge or an auxiliary battery or both, it is necessary to provide a connection between the caravan and the towing vehicle to provide power to these.
When such a connection is provided it is advisable to protect the vehicle's own battery from being accidentally drained by the caravan fridge and auxiliary battery.
The usual way of providing this protection is to install a suitable relay or pair of relays which will turn off the connections when the vehicle's alternator is not running.
These are Smart Combi relays, and are switched on and off by an internal voltage-sensing system that senses when the vehicle's alternator is charging the vehicle battery.
Older types, often referred to as "split-charging", "combination", or "Combi" relays, are either switched by a connection to the alternator or to some suitable ignition-switched source.
It is absolutely essential that any such relay system should work reliably, fail safe, offer full protection to the battery, and, if possible, to the auxiliary battery as well and meet relevant ISO, and BS standards and EMC regulations.
The Smart Combi, self-switching combination relays from Ryder Towing make the installation of Caravan auxiliary wiring safe and easy, especially in the context of the complex electronics in modern vehicles, and meet all the essential criteria described above.
See Caravan Relays for full range of relays and fitting details.