So, for the last 2 months I've been chasing voltage issues. I have replaced my battery, battery cables (both positive and ground), and alternator. I drive 40 miles to/from work and no voltage issues at all. But, when I'm driving local - when I goto idle the voltage drops to 12.3 volts (with no accessories on). It will sit there for a minute and pop back up to 14.3. This did it with both the new and old alternator - exactly the same. I'm beginning to believe it is some other electrical wire in my car that needs replaced ie the alternator cables themselves. I see many posts that say check grounds. I see only one real ground wire, that is from the negative battery post to the car....cleaned it, and replaced the cable with genuine Honda cable.

 

sometimes when the car idles low... voltage will drop to 12v. as long as the battery is staying charged i would say this is normal and you are ok.

 

i had same issue and i made up some extra grounding cables, had one from the battery to the body and another to engine.

 

I'm really thinking it's the voltage ECD...cuz if I get a drop, and turn on the lights, it bumps back up to 14.2 and never fluctuates...but if the headlights are off, it drops to 12.7 and jumps back and forth between 12.7 and 14.3

 

Sounds normal. It's the ELD giving the alternator a break when demand is low.