Normal Car Battery Voltage When Off

May 14, 2021 Post a Comment

Car battery voltage will change depending on its condition. To get a true voltage reading of the cars battery it is important to measure the voltage after the car has been sat for a period with the engine off, preferably overnight, this provides you with the “car battery open circuit voltage” or also know as the “resting voltage”.

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You should measure right on the battery posts and then again on the cable terminals.

Normal car battery voltage when off. If the voltage is not 12.5+, the battery is dying. With the engine off, you should get a reading of 12.6 volts. Optima says that when the battery's voltage reaches 10.5 volts that it needs charging.

Do remember that battery voltage readings are temperature dependent. How old is the battery? A fully charged car battery voltage should be 12.6v or above, this is with the engine off.

In that case, the voltage drops to 11.9 v. That will tell you if your car's internal gauge is reporting accurately or not. A fully charged battery reads 12.6 volts, disconnected and idle for over an hour.

Remember that this is not a valid reading since the alternator is actively charging it. By the way, 14.2 v is not too high when charging. If measured at this point, the battery reading you will get will be anywhere between 13.5 to 14.7 volts.

If you don’t have the proper diagnostic tools or multimeters to tell you the voltage, you can perform some electrical tests yourself. Is 14 volts good for a car battery? When the car is off, the battery is still a 12v battery, and a 12v system in the car.

When the engine is off the battery open circuit voltage is 12.9 volts. So between 50f and 80f could have a 10% difference in charge state. I suspect you are getting 12.7 immediately after switching off the engine and it drops to 12.1 in the same time scale.

That’s the normal process of how an alternator works. A guide for 12v car, commercial, leisure and marine batteries. What is the normal car battery voltage when it runs out of juice?

Obviously, a 60ma drain over 2 days shouldn't drain a full volt off the battery. Once the vehicle is running, the alternator will kick in and take over the task of powering the car while also recharging the battery. Disconnect your plug from the tender and connect it to a voltmeter instead.

That voltage, with no load, is for a nearly discharged battery. It outputs a higher voltage than the battery so that it charges the battery. You can connect a charger whilst the battery is in the car.

The ideal car battery voltage with the engine running is between 13.7 and 14.7v. I charged the battery up again today to 12.3v. The standing unloaded battery voltage, after the vehicle has been off overnight without load, should be very close to 12.6 volts.

I would think that at 10.5 volts the battery probably wouldn't crank the engine enough to start it. When the engine is running and functioning correctly, the car battery will fluctuate between 13.7 and 14.7 volts. When the car is running.

I've been working on cars for 30 years, and this is how all of them have measured. Then the leads are connected to the battery terminals, positive to positive and negative to negative to get the voltage. Secondly pulling voltage down to less than 50% remaining capacity permanently devalues the battery.

A 12 volt battery contains 6 x 2 volt cells but 12v is the nominal voltage. For really serious work advisable to take temperature of the battery acid for standard lead acid batteries. Measure the voltage after an overnight charge, and 1 hour after disconnecting the charger.

The actual open circuit voltage of a 100% charged battery is between 12.70v and 12.80v because each cell is approximately 2.13v. But if the battery reads over 15 volts or less than 13 volts, then there might be a problem with the voltage regulator, the wiring or the alternator. The charging/system voltage should show 14.2 to 14.6 at all times above idle.maybe 13.9 at night, idling, with everything turned on.

This does not mean the battery is good and not having 12.6v does not mean it is bad, it just means the electrical system and battery should be checked. How to test a car battery voltage. A fully charged car battery has 12.6 volts.

I think optima considers a battery to be basically discharged if it's voltage is 10.5 or less. A dead battery reads 11.9 volts under the same conditions. It should read close to 12.6 volts when the car is off.

There is a very big difference when a car battery drops even a small amount of voltage. A good battery should be between 12.4 to 12.6v at rest, it will drop some if any accesories are on (lights, radio, phone or gps chargers, flashers, etc) if you have an automotive voltage/amperage tester available, you can do a load test on the battery (hook it up and load it by 1/2 the cca rating of the battery for 15 seconds) if it drops below 10v, it's time for a new battery. If you measure the voltage immediately after the end of a drive, it should be more like 13.2, and drop to 12.7 within a few minutes as the chemical reactions in the battery slow down and stop when you stop charging it.

So, the voltage has to be at least 12 for a car battery to have the functioning capacity. If is is lower on the terminals you have a bad connection usually caused by. You said you have a tender.

12 volts is the standard automotive battery in today’s vehicle and each of the battery has 6 cells with a voltage of 2.1. Keep the trunk and battery compartment open when charging. If the battery isn’t fully charged, it will diminish to 12.4v at 75%, 12v when it’s only operating at 25%, and down to 11.9v when it’s completely discharged.

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