12
Mac Plus
–
User and Installation Manual
Remote switch input
The remote switch input (pin 4 of the Accessories connector) can be used to enable and disable the
battery charger. In a vehicle application, it is recommended to connect the engine run signal. This
way, the charger is used when the engine is running and the alternator is charging. The engine run
signal can be provided in different ways. For details contact your vehicle distributor.
The remote input accepts two different enable levels:
• active low, connect to ground (between 0 and 0.5 V)
• active high, connect to + battery voltage (between 3 and 32 V)
Active low means active when input is low. Active high means active when input is high.
The remote switch input configuration can be done by DIP switch (see chapter 7) or by MasterBus
(see chapter 9 and 10).
Battery temperature sensor (included)
By installing the Mastervolt temperature sensor, the charge voltages are automatically adapted for
deviating temperatures.
Figure 1. Temperature compensated charging
When the battery temperature is low, the charge voltage increases. In case the battery temperature
is high, the charge voltage is decreased. Over charge and gassing are prevented this way. This will
extend the life of your battery.
Voltage drop compensation
The Mac Plus can compensate the voltage drop occurring over the output cables. For this purpose,
the Mac Plus is equipped with terminals for voltage sense wires. Use 0,75 mm
2
[
AWG
18], preferably
red and black wire and protect these with a 2 A fuses slow blow. Pay good attention to the polarity
of the wires.
In order to accurately measure the battery voltage, connect the voltage sense wires as close to the
battery poles as possible. The positive and negative voltage sense wires must be connected. Cable
losses will be compensated up to a maximum of 2.5 V.
