Intellitec's Battery Isolator Relay Delay/E offers a low cost, reliable approach to charging multiple batteries. Unlike diode isolators, this system provides an engine driven alternator with the opportunity to begin charging the main battery before connecting the auxiliary battery. This allows the use of self-exciting alternators and lets the engine briefly warm up prior to placing the load of a heavily discharged auxiliary battery on the alternator. The unit is available in both 12 and 24 Volt versions. The unit is fully encapsulated in a plastic enclosure for mounting in the engine compartment with two screws. It operates in combination with a conventional continuous duty cycle isolator relay that has been used by a number of vehicle manufacturers. There are three (3) wires to connect to the delay unit: one from an ignition switched 12 Volt source, a ground and the isolator relay coil. It operates by sensing the voltage on the main 12 Volt system. When this voltage goes above 13.3 Volts for approximately 12 seconds, as happens when the engine is running normally (normal alternator output voltage is approximately 14.4 Volts), it will close the isolator relay providing charging current to the auxiliary battery. When the ignition switch is turned off, the relay will open immediately.