The Intellitec Battery
Isolator Relay Delay offers a new approach to
charging and isolating dual batteries in an RV. Unlike conventional
diode isolators, this system provides the engine driven alternator with
the opportunity to begin charging the chassis battery before connecting
the coach 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 coach battery on the alternator.
The unit is packaged in a plastic enclosure for mounting in the engine
compartment with two flathead screws. It operates in combination with a
conventional continuous duty cycle isolator relay as has been used by a
number of RV manufacturers. There are three wires to connect to the
delay unit, one from an ignition switched 1 2 volt source, a ground,
and the isolator relay coil.
It operates by sensing the level of voltage on the chassis 12 volt
system. When this voltage goes above 1 3.3 volts for approximately 1 2
seconds, as happens when the engine is running normally (normal
alternator voltage is approximately 14.4 volts), it will close the
isolator relay providing charging current to the coach battery. When
the ignition switch is turned off, the relay will open immediately. If
the voltage should drop below 1 2 volts for more than two seconds while
running, the relay will drop out. This might happen when the alternator
is not able to supply sufficient current to all of the loads.
If the chassis voltage goes above 1 3.3 volts again, the relay will
close again in about two seconds and retry to charge the battery. The
resultant flickering of lights would alert the owner of the system
overload.
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