INSTALLATION CABLE SIZING
Cables & any connectors should be selected to carry the following maximum current:
Model
Input current (maximum)
Output current (maximum)
All models
15 amps
33 amps
12 amps
30 amps
Input cables
The line charger will operate successfully with the input voltage as low as 12 volts, however,
this will reduce the output power available for battery charging. The higher the input voltage,
the greater the available charging current. The table below lists the approximate input
voltage drop for various cable sizes (at full output):
Cable size
Volts drop per 10 metre length
2.5mm
2
1.1 volts
4mm
2
0.7 volts
6mm
2
0.4 volts
10mm
2
0.25 volts
Each volt lost in the input connection will reduce the available output charging current by
approximately 0.5 amps.
Output cables
Any voltage drop in the output cables will also reduce charging effectiveness, however, the
remote battery sensing option (if used) will overcome any volt drop by raising the output
voltage to compensate. The amount of compensation is limited to 0.7 volts.
If remote sense is not used, output cables should be sized to keep the voltage drop below
0.1 to 0.2 volts at 10 amps.
The table below lists the maximum total output cable length (positive plus negative) for
various cable sizes when remote sense is not used:
Cable size
Maximum length
(0.1volt drop)
2.5mm
2
1.4 metres
4mm
2
2.3 metres
6mm
2
3.4 metres
10mm
2
5.9 metres
Suzi connector
The line charger may be used through the 12N/S or 24N/S trailer sockets, to charge a trailer
battery (The line charger is mounted on the trailer, near the battery). You should check that
both the tractor & trailer wiring to the connector pair is adequately sized for the current and
suitably fused. Typical “7 core trailer cable” will have one 2mm
2
conductor rated at 17 amps
& six 1mm
2
conductors rated at 8½ amps each. In this case, two conductors & two pins on
the connector will have to be used for the input positive supply. Check your vehicle’s wiring
arrangement to determine which, if any, of the socket pins have power available and that the
wiring is adequate to support the load.
If the 15 amp input line charger is used, then there is only one or two amps spare capacity on
the 12N/S/24N/S connector earth for other trailer loads. To allow for the possibility that other
loads are required, the alternative 12 amp input line charger allows 5 amps spare.
Note that “heavy duty” 12S/24S connector sets are available, rated 70 amps, & able to take
up to 6mm
2
sized cables.
DC Charger User Manual, Part No. 13328 Issue 5
