Ok guys this has bothered me so much i just have to ask. My cars voltage is so weird it is a 1995 Honda Civic Ex w/vtec. I just got a HO alt and when i am parked with the car on the voltage will stay at 14.4v maybe 14.2v with the system really loud. So my alt it good. The wierd thing is that i have a pioneer premier 680 and it has a voltage meter that reads different than my cap does. For example when my car sits at 14.4v the hu will display 14.0v. Now when i drive the car it stays around the same voltage until it warms up, then my voltage just goes to 12.7 at the cap and 12.3-12.4v at the hu and for some reason and it only increases to 14v until i go over 40mph or if run some sort of accessory like the windows or turn on lights. Does the car further regulate the voltage after the alt and then increase when the internal loads are used. This sucks because i have to go over 40 to have a high voltage and if not my voltage sits at 12.7v and any further drops take from the bat i guess, right? Well if anyone has any info or explanation why this might happen i would appreciate the help. Thanks
don't use the voltage meter in the HU. mine is almost 1.4 volts off from what a meter on the battery or amp will say.
and the HO alt only kicks on around 1500-2000rpms. any lower and its just like stock almost. so when your driving, you should be sitting 13.8+, but when you stop at a light and have the system going, its not supprising to hear your voltage drops to around 12.
yeah but thats even with the system off. When my car is warm it will idle at 12.7v and not go any higher until i pass 40mph or i use an accessory such as my power windows. Thats the wierd thing if i stop and go any speed below 40 my voltage stays at 12.7. Oh well, do your cars do that or do they idle above 12.7v when you drive?
Don't alternators only give out the power when the power is necessary? I thought was how it worked... that would explain why using power windows at 12.7 causing a jump up in voltage. This is all off the top of my head I'm not for sure.
alternators do only out out the power thats needed, but it should still sit higher, especially with the system off.
my car sits at 13.X at idle when its hot and thats with everything going. it'll stay at 14.X if i turn everything off or i'm driving at 1000rpms and up.
have you tried to test your battery and make sure its good. you might have a bad cell and that would create a voltage drop. let it sit for a couple hours and see what the voltage is. if its below 12.6, then its time for a new battery.
also, how are you measuring the voltage?? use a meter and put it on the battery or on the alternator (do both and compare). do this when its at temperature like after you drive home. measure in park at idle and at higher rpms then get someone you trust to put the car in gear and see what it sits at then.
you shouldn't drop below 12.6 or whatever your battery sits at when left over night.