How to work out the correct Battery Cable for the job

The following Data acts as a guide only. We cannot be held responsible and advise the Customer to consult a qualified Auto Electrical Engineer, if in doubt, when choosing cable

Cable descriptions give the number and size of cable strands, the total cross-sectional area of the conductor, the outside diameter and the current rating. For example, FLEX 16 Cable Conductor Specification: 203/0.30, 16mm2, 110A, 8.3mm indicates that the cable has 203 x 0.3mm diameter strands of copper, giving a cross sectional area of 16mm2, the outside diameter of the cable, including the insulation, is 8.3mm and the current rating is 110amps

Working out the size of cable you will need: If you know the amperage of the component you are wiring, then choose the next size cable up allowing a fair amperage capacity margin.For example, if your component uses 100amps of continuous current, choose Flex20 (rated at 135Amps) If you know the wattage of the component to be wired, and you need to know what the amperage is, divide the wattage by 12volts and allow a fair amperage capacity margin. For example, if the wattage of the component is 2800watts divided by 12volts =233amps. In this case choose Flex40 (rated at 300amps) cable. Inverters: When buying cable for inverters divide the wattage by 10volts. Volt drop: The longer the cable the more resistance, the more Volt Drop will occur. To reduce the Volt Drop, use a larger capacity cable. 

FAQ’S 

Q: I’ve got a 100amp Battery what size cable do I need? 

A: It’s not the size of the Battery, it’s the amperage or the wattage of the items that you are running from the Battery that determines the size of cable you require. To calculate the size of the cable you require you will need to know the total amperage of the items you wish to run from the Battery

If the total amperage is 108amps the advised cable, to allow for margins, would be 135Amps 20mmsq cable

If you do not know the total amperage, but know the total wattage of the items you are running from the Battery, you can calculate the total amperage by dividing the wattage by 12

e.g. if the total wattage of your items is 120watts, divide 120 by 12=10amps

Q: I have a 2000watt inverter what size cable do I need? 

A: If the inverter is rated at 2000watts you will need to calculate the amperage to find the required cable

To calculate the amperage you divide the wattage of your inverter by 10

e.g. if the total wattage of your inverter is 2000watts, divide 2000 by 10=200amps the advised cable would be 240mps 35mmsq cable 

Highly Flexible PVC BATTERY / WELDING CABLES

 

Part No

Conductor Specification (mm)

Conductor Cross Section (mm²)

Nominal Current Rating (Amps)

Maximum Overall Diameter (mm)

Resistance Per Metre At 20°C (Ohms)

Sheath Colours


FLEX 16

203/0.30

16

110

8.3

0.00126

Black, Red


FLEX 20

266/0.30

20

135

9.0

0.00096

Black, Red


FLEX 25

322/0.30

25

170

10.1

0.00077

Black, Red


FLEX 35

455/0.30

35

240

11.8

0.00056

Black, Red


FLEX 40

539/0.30

40

300

12.7

0.00050

Black, Red


FLEX 50

637/0.30

50

345

13.3

0.00039

Black, Red


FLEX 60

805/0.30

60

415

15.0

0.00033

Black, Red


FLEX 70

912/0.30

70

485

15.5

0.00029

Black, Red


FLEX 95

684/0.40

95

500

17.9

0.00020

Black, Red


FLEX 120

888/0.40

120

600

19.7

0.00015

Black, Red


FLEX 150

1184/0.40

150

700

22.0

0.00011

Black, Red

 

 

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