Need A Quick Response!
Thread Starter
Pro
Joined: Jun 2004
Posts: 560
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From: Prattville AL
Need A Quick Response!
How many volts on the batterey should my DIC read if the car is not cranked, but the ignition is turned on? My car has been having issues with cranking for the past couple days. Im trying to see if the battery is dead. The car is 8 years old and the battery is an aftermarket one, but I dont know old it is. All I know it was in there when I got the car in July 04.
Melting Slicks
Joined: Nov 2005
Posts: 2,071
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From: clackamas oregon
Well i just checked mine for ya. it reads 11.9 with the radio and air fan turned off. did flutter for a few times to 11.8. my battery is fairly fresh. less than a year. when running it hovers around 14.2
Thread Starter
Pro
Joined: Jun 2004
Posts: 560
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From: Prattville AL
Without the engine on, it showed 11.7 to 11.8. I had no warning signs until this weekend when the radio lost its time. Yesterday, I was stuck in the WalMart parking lot for about 15 minutes when it wouldn't crank. After attemps to jump it off, my father got it to crank after playing with the battery cables. He said they were loose and tightened them up once I got home. Car worked fine until this afternoon after having my new wheels installed. Just now, it didn't want to crank, just like yesterday at Walmart, but dad did manage to get it cranked when I first started typing this. Any ideas?
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
A 12-volt battery will measure at about 12.9 volts when it’s fully charged and about 11.4 volts when it is fully discharged. Now that is without any load on it, no fan, no radio, no interior lights or DRL lights. Best way is to measure battery with ignition off.
Thread Starter
Pro
Joined: Jun 2004
Posts: 560
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From: Prattville AL
All of the lights work properly, so we think it may not be the battery. It was having issues yesterday when we noticed the battery cables were loose. They were disconnected to check for corrosion, then reconnected.
Drifting
Joined: Sep 2004
Posts: 1,737
Likes: 349
From: Layton Utah
I've noticed on my 04 Coupe that if the car is only run on short trips etc, that the battery will become weaker and weaker. If I take it out on a longer drive, it starts to charge back up. There is a lot of electronic gear in the C5 that puts a drain on the battery over time. One thing you can do that works for me is to put a battery tender on it when not in use. It keeps the battery charged so that during the around town trips, it will still start very easy. Hope that helps.
Melting Slicks
Joined: Nov 2005
Posts: 2,071
Likes: 0
From: clackamas oregon
you have checked the terminals right??
vett's are known for ground issues. i think it was bill curley who did a write up on this. there are a bunch of ground points that get all mucked up by corrosion. do a search on "ground" you may find it
mine only shows 11.8-11.9 like i said, and it never has even begun to not crank over. sounds more like a ignition or a problem with ground. or the unbelieveable--------- check your terminals!!!!!! take them off, look at them, clean them up with a brush, put them on, and tighten. just may work. good luck, ron aka rgtkst
by the way what is the volt meter say when its running?
you may have a bad battery cable. corroded inside where it meets with the terminal head.
check the terminals!!!!!!!!
vett's are known for ground issues. i think it was bill curley who did a write up on this. there are a bunch of ground points that get all mucked up by corrosion. do a search on "ground" you may find it
mine only shows 11.8-11.9 like i said, and it never has even begun to not crank over. sounds more like a ignition or a problem with ground. or the unbelieveable--------- check your terminals!!!!!! take them off, look at them, clean them up with a brush, put them on, and tighten. just may work. good luck, ron aka rgtkst
by the way what is the volt meter say when its running?
you may have a bad battery cable. corroded inside where it meets with the terminal head.
check the terminals!!!!!!!!
Last edited by rgtkst; Apr 18, 2006 at 12:00 AM.
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Race Director
Joined: Nov 2003
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From: Mustang OK
As you and others are seeing there will always be a certain amount of voltage drop in the wiring from the battery and you can not get an accurate reading as to your battery's state of charge by relying on the car's voltmeter or DIC. In order to get an accurate reading, you will need to take a reading directly at the battery terminals using an accurate digital volt-ohm multimeter (DVOM). If you have recently driven the car or charged the battery, you will need to remove the battery's surface charge before taking the reading. The internal temperature of the battery will also come into play, but a fully charged battery should read about
12.8 V at 75 degrees F.
The following link contains some excellent info on automotive batteries and Section 6 goes into the proper way to test automotive batteries:
CAR BATTERY FREQUENTLY ASKED QUESTIONS
Hope this helps.
12.8 V at 75 degrees F.
The following link contains some excellent info on automotive batteries and Section 6 goes into the proper way to test automotive batteries:
CAR BATTERY FREQUENTLY ASKED QUESTIONS
Hope this helps.
Last edited by GrayC5; Apr 18, 2006 at 12:45 AM.