battery relocation and starter motor feed

[ben_p]

half way running my battery to the boot, i was thinking last nite that the starter must draw Phat amps to turn the crank, do i need to run its own feed to it? as arnt the amps reduced the further the battery is away? (longer lead)

 

[Fred@BTM]

nope, 1 cable runs the length of the car (earthed to the shell at the back)

i go into a junction box inside the fuse box and run a direct feed to the starter and fuse everything else

 

[VXR killer]

voltage reduces with length not current, called voltage drop.

 

[GordonD]

voltage reduces with length not current, called voltage drop.

Wrong.

The resistance of the cable is higher the longer it is. So the longer the cable is the higher the combined resistance of the cable plus the starter motor is, and the less current flows.

The fatter that cable back from the engine compartment to the battery in the boot is the lower its resistance will be per metre, and the less in total, and the less the voltage drop at the starter motor will be, and the less the reduction in the current available to it will be.