Low battery voltage
Thread Starter
Racer
Joined: Apr 2011
Posts: 296
Likes: 1
From: Tipp City Ohio
Alternator output cold is 14.7 volts and the dash voltmeter will always read 0.3 volts lower due to voltage drop across the ignition switch contacts. The alternator is designed to reduce its output voltage with increasing temperature and your dash voltmeter should read 13.3 volts approximately when the alternator gets to its operating temperature.
Instructor
Joined: Jun 2002
Posts: 154
Likes: 3
From: San Diego CA
Cranking a completely dead car will put a lot (too much) load on the good car and can blow a diode in the alternator. It is a little known issue. One diode out will make the alternator weak, but it will still function. This is why I always let a completely dead battery get 10-15 minutes of charge before trying to crank it.
Cruising
Joined: Oct 2010
Posts: 10
Likes: 0
Hi Voltage
Hi Guys
I have and 85 corvette and I am showing high voltage on the digital dash 18.2. I battery is new and today I changed the alternator, still the same shows the red alarm bar and 18.2 volts. Any thoughts would help, Wayne
I have and 85 corvette and I am showing high voltage on the digital dash 18.2. I battery is new and today I changed the alternator, still the same shows the red alarm bar and 18.2 volts. Any thoughts would help, Wayne
Last edited by whmartin98; May 25, 2013 at 07:05 PM. Reason: added info
