battery voltage when car is off
11-20-2017, 06:54 PM
#1
battery voltage when car is off
im just wondering i went to work today and 8 hours later before turning the car on, i went into accessory mode and checked that the battery voltage said 11.1. is that voltage normal? once i turn the car on it goes to 14+
11-20-2017, 07:01 PM
#2
Melting Slicks
That is very normal. When your engine is off, the gauge is showing the battery voltage; when the engine is running, it is showing the alternator voltage output, not the battery voltage, and it should read somewhere between 13-14 
11-20-2017, 07:02 PM
#3
iv had a couple issues of my car just saying press brake to start engine, and it wouldn't crank, then it cranked by itself like there was a lag in the system. weird
11-20-2017, 07:10 PM
#4
Melting Slicks
Not sure what is causing your issue, could be the sensor/switch that indicates the brake is depressed is going bad. A far as the battery goes, although the voltage is showing OK, it could still be bad and not holding the charge under load. You can take it to your local auto parts store and have it tested for free.
11-20-2017, 07:10 PM
#5
Pro
Actually, 11.1V is quite low for a battery to read, and not normal. The normal resting voltage of a fully charged automotive battery is between 12.4 and 12.6 volts. I suspect your battery is going to need replacement soon.
Garry
Garry
11-20-2017, 07:10 PM
#6
your right i should check it tmrw morning before i go to work. worst come worst il get a new battery after storage. since this is the final week of driving for me im going to be putting on the tender on it until spring
11-20-2017, 07:27 PM
#7
this is a problem in the cold and some mornings right now it does start with a little shake, other times its very smooth startup, i had this last year too. late fall it happens. spring and summer its fine that's why im ruling out battery not to mention theres some white stuff around it too.
11-20-2017, 07:40 PM
#8
I'm speculating, but it sounds like the cooler weather is making a bad battery rear it's head more boldly than in nice weather.
If the engine is cranking slower you'll for sure notice the labored "shaking" sensation. Not so much a fluid spin of the engine like when it's warmer out.
If the engine is cranking slower you'll for sure notice the labored "shaking" sensation. Not so much a fluid spin of the engine like when it's warmer out.
yess im thinking the battery is on its way out the door if its showing these signs in colder weather
11-20-2017, 07:50 PM
#9
I agree.
If you do pick up a new battery, I would buy a battery kit with it (battery terminal cleaner, acid neutralizer, positive/negative post pads, and terminal sealant spray).
The kits are cheap, and will take care of any future white fuzzy alien life that grows on battery terminals. I use one on each new battery. They are like $10 per kit and available at any parts store in the battery section.
If you do pick up a new battery, I would buy a battery kit with it (battery terminal cleaner, acid neutralizer, positive/negative post pads, and terminal sealant spray).
The kits are cheap, and will take care of any future white fuzzy alien life that grows on battery terminals. I use one on each new battery. They are like $10 per kit and available at any parts store in the battery section.
11-20-2017, 08:27 PM
#10
Le Mans Master
Member Since: Sep 2014
Location: lake havasu city arizona
Posts: 7,011
Received 982 Likes
on
711 Posts
NSF
11-20-2017, 08:29 PM
#11
mine showed 11.1 after sitting for 8 hrs. i bet tmrw morning itl be even lower. im sure yours is normal lol
11-21-2017, 07:48 AM
#12
Race Director
That's low NSF. Depending on what the VM has to say, it might be time for a new battery.
11-21-2017, 10:11 AM
#13
Burning Brakes
Just opening the door or putting into accessory mode will drop the
battery voltage for a short while.
Check it at the battery some morning when the hood is already open.
battery voltage for a short while.
Check it at the battery some morning when the hood is already open.
Last edited by Spark 2; 11-21-2017 at 07:18 PM.
11-21-2017, 10:30 AM
#14
Team Owner
Member Since: Mar 2014
Location: Below the bottom of Berby Hollow, NYS
Posts: 21,631
Received 1,136 Likes
on
882 Posts
Disconnect the tender. Ideally, the surface charge should be off first. Let the battery sit untendered for a while or turn the headlights on for a minute, then check. Using a separate v-meter, touch the probes directly onto the battery terminals, not the clamps.
As already mentioned, ideally it should measure 12.6 volts (each cell produces 2.1 volts). But that doesn't mean the battery will produce enough current to start the car, only that it has 12.6 volts. It still can be weak.
If it measures 12 v. or below, I would definitely have it load tested.
Beyond that, ask Ft. Morgan Al or Dano.
As already mentioned, ideally it should measure 12.6 volts (each cell produces 2.1 volts). But that doesn't mean the battery will produce enough current to start the car, only that it has 12.6 volts. It still can be weak.
If it measures 12 v. or below, I would definitely have it load tested.
Beyond that, ask Ft. Morgan Al or Dano.
11-21-2017, 10:46 AM
#15
Le Mans Master
Member Since: Sep 2014
Location: lake havasu city arizona
Posts: 7,011
Received 982 Likes
on
711 Posts
That's 4 years and in this summer heat we have that's very good, so off to AutoZone I will go
NSF
11-21-2017, 04:00 PM
#18
Race Director
Anything below 12vdc indicates a battery that is near death.
