I have a 2006 civic ex coupe with 1.8L engine. I have replace the alternator and have a brand new battery. The car had to be jump started 2 days after I replaced both. I have a scan tool and am getting no codes. With the scan tool plugged in, I notice my module voltage is 14.5 at idle and it’s 14.5 over 65mph but at speed below 65 the voltage drops to 12.5. This doesn’t seem normal to me. Can anyone help explain this?

 

what's the problem? It won't charge? how long did you recharged the battery. Make sure to recharge with nothing electric ON such as AC FAN

 

I charged the battery on a battery charger all day before I put it in the car. I have used 3 batteries so far and all are fully charged going into the car and die after a few days. Brand new alternator. Car is showing 14.25 volts at idle. All grounds have been cleaned and appear to be working properly. New alternator that appears to be working properly. I’m at a loss. At first I was thinking I didn’t have a parasitic drain but now second guessing that. Also thought about pulley tensioner may not be making belt as tight as it should be but just guessing at this point.