Why might a car be running at 19 volts?

While the engine is off, but ign is on, car sees 13-14V… which is what it should see while its running… instead it sees 17-20V while its running… 17V at idle and higher as you rev…


really good alternator

voltage regulator on the alternator is bad, nvm…

if its seeing that much voltage with out the car on, then it has nothing to do with the alternator.

thats fucking wierd, what is the voltage of the battery disconnected???

nah, its the voltage regulator on the alternator… the battery is 13V when the car is off… its over charged because the alternator is putting out an unregulated 19V when the car is running… so its kind of over-charging the battery…

edit: oringinally it came in because the radio wasnt working when you rev’d the engine… so anything over idle the radio shut off… tested it w/a test light, ground and power wires were good, none of the speaker wires were grounding out… then i metered the wires… 19V at both power wires… so i tested it at the ign switch and i was just going to run new power wires from the ign harness… that too was 19V… tested at the battery… 19V there too… cept when the car is off, then its all 13V

That symptom is always the voltage reg. Internal and external regulators are known for going but 99% of the time when an alternator mounted regulator goes you have to get a new alternator. Glad you have it figured out!

is that what you were doing all evening/night outside of the Stereo Advantage Install shop?

no lol… this was a customers car…

outside all night was me working on my own car… needed new RCAs, aux adaptor for the pioneer radio, and had to run a new trunk pop wire from the switch to the keyless module…

was the battery acid boiling out the terminals? . i saw that happend the other day it was cool after the chem burn

I would imagine that battery won’t last too long after that incident.

What timing for this thread. I just killed a 4 month old $90 battery by an overcharging alternator, that is also 4 months old from Carquest.

Needless to say, not too happy right now.

Hopefully the alternator will be covered under the warranty. But odds are I’m at least out $60 on the price of a battery.