10 •
INSTALLATION EXAMPLES
PREREQUISITES
A dual battery system, where the D250T
charges a service battery from the vehicle
alternator when the motor is running.
Use this installation when the priority is to charge
and maintain the service battery with the opti-
mum charge voltage, and when there are no, or
minor, parallel consumers that need power when
the vehicle is running. Parallel loads will reduce
available charge current and extend charging
times. If you are charging parallel consumers,
we recommend you also install a SMARTPASS
120T. See installation example #3.
Use this installation when:
– Priority to charge the service battery with
optimum voltage.
– No or minor parallel consumers
to Service battery.
– Service battery capacity up to approx.
150 Ah, for larger batteries the charging time
will be too long.
1. Small service battery
PREREQUISITES
SMARTPASS 120T connects the service battery
with the alternator/starter battery in order to split
charge and supply up to 120A continuously to
the service battery and parallel consumers.
Use this installation when the priority is to
manage larger consumers parallel to the service
battery that require power when the vehicle is
running.
One basic condition required for this installation
is that the alternator can deliver sufficient voltage
to supply equipment and split charge the service
battery. If the alternator is not able to provide
enough voltage to fully charge the battery, the
SMARTPASS 120T will not either. In this case,
we recommend that you also install the D250T
DC/DC charger.
Connect the cabling from the starter and service
batteries respectively to the SMARTPASS 120T
and not to the D250T.
Use this installation when:
– Large electrical consumers parallel
to service battery.
– Alternator able to provide the desired voltage
– Power management is priority.
– Larger service battery capacity up to 800 Ah.
2. Service battery with parallel consumers
*See ”CABLE AND FUSE REQUIREMENTS”
*See ”CABLE AND FUSE REQUIREMENTS”
STARTER
BATTERY
STARTER
BATTERY
SERVICE
BATTERY
SERVICE
BATTERY
STARTER
BATTERY
STARTER
BATTERY
SERVICE
BATTERY
SERVICE
BATTERY
I
t
I
t
D250T charges service battery with
10A until the battery reaches max
voltage. The current then tapers off
to a fully charged battery.
Power is forwarded directly from
alternator to the service battery.
High current initially (up to
30 minutes) Current tapers off to
very low level 100% charge from
alternator is not possible to reach.
Max. 100A
