Battery Cable Sizing

[BRRT]

Came across this chart today. The current draw allows for a 20% voltage drop at the length shown, which would give you 9.6 volts at the starter.
Shows the affect cable length has on voltage drop.
https://thefactoryfiveforum.com/attachment.php?attachmentid=190454&d=1695747575

Stolen from the Waytek Wire web site.

[Alan_C]

A consideration to take into account is what the cars electrical requirements are with respect to EFI vs. non-EFI. Modern electronics do no like low voltage and can malfunction if you do not have sufficient voltage.
The Ford Performance control pack for example, warns folks not to have main power runs in excess of about 10 feet. You can deal with this many ways, like increasing the gauge of the main cable and the location of where you source your 12V. Virtually all modern aftermarket EFI systems tell you to make your power connection direct to the battery terminal. Why, to minimize the voltage drop to their ECU.