Car Battery Cable Size Calculator

One of the most important aspects of designing and building any part of a vehicle electrical system is determining the correct size and type of cable to use for each circuit.

Car battery cable size calculator.

The rating of the battery reduces by approximately 62 if it is discharged in 1 hour. The following maximum amps versus cable size awg come from the nec version 2011. However when the 2 105 20 hrs batteries in parallel are used and then put on charge after use the batteries typically register 50 charged. In summary when selecting the correct size of battery cable you need to take into account the total maximum amperage your electrical system requires the voltage of your system usually 12 volts the total length that your cables need to be and the amount of voltage drop you are willing to accept versus the amount you want to spend.

Choosing the correct gauge automotive wire depends on the acceptable voltage drop length of the feeder branch circuit conductor load amperage and the ambient temperature of the compartment where the primary wire will pass through. So all interconnecting cables are 2 0 based on the chart below. Automotive wire size calculator this is a simple calculator for determining approximate wire gage size based on the length of the wire in feet and the current in amps in general automotive applications. Average run cycle is 10 hours.

Battery cable is used to power your electrical system and is sized according to the american wire gauge or awg for short specification for electrically conductive cables. As far as i know these values are valid as of today. Actually for my current installation i ve sized all of my dc cables to meet the 175 amp worst case scenario. Our battery cable is american made and comes in gauge awg sizes of 6 4 2 1 1 0 2 0 3 0 and 4 0 with 6 gauge being the smallest and 4 0 gauge being the largest.

Too small a cable size and you ll run the risk of generating heat in the cable. Outside engine compartments the ambient temperature should generally be 20 c. Using the inverter calculator indicates 14 35 amps dc load and then running the sizing calculator suggests that i need battery capacity of 306 ah 20 hrs. You may want to consider 600 800 amp hours of capacity based on this example depending on your budget and other factors.

The battery size calculator derates the battery linearly based in this characteristic. For example if the same 20 ah battery is discharged in one hour it can only deliver 12 4 a for one hour which amounts to 12 4 ah. Cable sizing selection. This can be helpful if doing your own repairs or adding custom wiring to make sure each circuit is not overloaded.

Cable size ampacity chart. Too large and you ll be wasting money on copper you don t need.