Size of Charging Wire (Alternator to Battery)

[RedEye]

Hey Guys, Having some trouble with my voltage and my battery getting drawn down, especially on night drives with headlights. Did all the usual tests, alternator and battery are both new (less than 4K miles), and both tested fine.

I have a GM single wire (yes on a SB Ford) alternator and the wire which runs from the alternator to the to a Red Top Optima battery is a #8 stranded copper.

My starting cables that run directly from the battery were custom made from welding cable, so I know these have tremendous capacity. I'm wondering if the charging wire is too small.

What size charging wire do you guys have on your builds? Any recommendations?

[RedEye]

Can also note that the alternator is a 130 amp. Probably overkill, but does not explain why I'm normally running between 11-12 volts on the meter.

[joyridin']

You have something else going on there. 8 gage wire is fine, so that isn't the issue. If you are getting only 11-12 volts on the meter, then your alternator is bad or your battery is toast. We will rule out the battery since you can start the car without a problem, but it might not be a bad idea to do a load check on it.

You do not mention the pulley ratios. Is it possible the alternator is not turning fast enough when you drive? What happens when you rev the engine? Does the voltage go up?

[Dwight]

dido what joyridin' posted



check the battery volt then crank the motor and check it again.

You should read 12 v plus and when you crank the motor 13 volt plus

Dwight