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The DC input circuit is required to handle very large DC currents and hence, the size of
the cables and connectors should be selected to ensure minimum voltage drop between the
battery and the inverter. Thinner cables and loose connections will result in poor inverter
performance and will produce abnormal heating leading to risk of insulation melt down
and fire.
Use oil resistant, multi-stranded copper wire cables rated at 90 º C minimum. Do not use
aluminium cable as it has higher resistance per unit length. Cables can be bought at a
marine / welding supply store
The cables from the battery to the inverter should be protected by a suitable, very fast
acting DC fuse. Use a DC fuse of the appropriate capacity in line with the positive cable.
The fuse should be within 18” from the battery.
Type ANN fuses with Fuse Block 4164 made
by Bussmann are recommended.
The following size of cables and fuses are recommended. The distance shown is the
distance between the battery and the inverter. The recommended size of the cables will
limit the voltage drop to approximately 2% ( The length of the cable for calculating the
voltage drop has been taken as 2 times the distance between the inverter and the battery
assuming that two ( one positive and one negative)cables are used for the connection )
Distance up to 4'
Distance up to 6’
Ampere rating of battery fuse
PST-150S-12A AWG # 1/0
AWG # 2/0
300A (ANN 300)
PST-150S-24A AWG # 3
AWG # 2
150 A (ANN 150)
CAUTION!
The input section of the inverter has large value capacitors connected across
the input terminals. As soon as the DC input connection loop ( B
Y
Y
Y
Y
Y
fuse
Y
Y
Y
Y
Y
in
Y
Y
Y
Y
Y
inverter -
Y
Y
Y
Y
Y
battery negative) is completed, these
capacitors will start charging and will momentarily draw very heavy current
that will produce sparking on the last contact in the input loop even when the
on / off switch on the inverter is in the off position. Ensure that the fuse is
inserted only after all the connections in the loop have been completed so that
the sparking is limited to the fuse area.
Using proper DC cable termination
The battery end and the inverter end of the cables should have proper terminals that will
ensure a firm and tight connection.
DC input terminals
The DC input terminals have a tubular hole with a set screw. A suitable pin type of copper
terminal should, therefore, be used on the cable end.
Do not insert the stranded bare end of
the cable directly into the tubular hole as the set screw will not pinch all the strands and will
thus make only a partial and loose contact
.
For thicker cables, a suitable adapter with pin
type of termination should be used.
There should be no stray wire strands protruding from
the terminals as these may produce a short circuit due to the close vicinity of the plus and
minus terminals.
A pair of pin type of terminal has been provided. Crimp these terminals on the inverter end
of the cable. The terminal can accept up to AWG # 1/0
