Golden_HVAC wrote:
There is a device that will monitor the chassis and coach batteries. If it finds the coach battery is above 13 volts and the chassis battery falls below 12.6 (or so) then it will energize a wire going to the chassis to coach battery relay. This allows automatic chassis battery charging.
Fred.
That device is called a
BIRD a Bi Directional Isolator Relay Delay.
It operates by sensing the voltages on both batteries.
When either of these voltages exceeds 13.3 volts for
approximately 1 minute, which happens when either battery
is being charged, the control will close the isolator solenoid,
connecting the two batteries together, charging them both.
(Normal charging voltages are from approximately 13.8 to
14.4 volts.)
After the solenoid has been closed, the system continues to
sense the voltage. If the ignition switch is off and the battery
voltage drops below 12.8 volts for approximately 1 minute,
which might occur when the converter is heavily loaded,
the solenoid is opened to prevent the chassis battery from
being discharged by the coach loads. When the voltage goes
above 13.3 volts again for approximately 1 minute, the solenoid
closes again. Thus always keeping the Coach as well as Chassis battery charged. Regardless of the parasitic draws on the chassis battery that run it down while sitting unused.
These are more useful than the battery minder type of charger because of the way it works, sensing where the charge needs to go and maintaining both chassis and Coach batteries.
Mine has worked flawlessly, keeping all batteries properly charged.
