Battery volts drop

[mln385]

Originally Posted by tpatodd

Hi all-

First off... Happy New Year!

Car is running great. Even the battery when day driving.

This note is more-so out of curiosity. I rarely drive at night but recently I noticed that when I drive with my lights on the voltmeter drops quite significantly. Normal is 13-14v. Lights on drops it to 10v or less.

Even worse, lights on, fans on, drops it to 8-9v.

Is this normal?

Battery is ~12months old (Duralast 26R-DL). Even when the voltmeter drops all seems well. The lights are not fading or flickering.

Again, not doing much night driving so was interested it what others experience.

Thanks!!

tpatodd

Your Alternator may be undersized for the loads, also Roush uses underdrive pulley's so this maybe it as well.