As soon as your engine is switched on it should increase to 13.7—14.7V. If it reads below 10V, your battery is going to die very soon. When it rises above 12.9V—while your car isn’t switched on—you have a problem. This can turn into a hazard for you or your car, so you need to find the problem and repair it.
What voltage is too high for car battery?
Check the reading. A fully charged battery will typically display a voltmeter reading of about 12.6 to 12.8 volts. If your voltmeter is showing a voltage anywhere between 12.4 and 12.8, that means your battery is in good shape. Any voltage above 12.9 volts is a good indicator that your battery has excessive voltage.
Is 14.7 volts too high?
Charging voltages over 14.7 volts can prematurely dry the battery by boiling out electrolyte, and increase risk of a battery hydrogen gas explosion. … Less than 14.3 would be a “weak” alternator or regulator. Much less than 14.2 at a fast idle is bad wiring, bad alternator or regulator, or a bad connection or fuse link.
What voltage is too high for a 12V battery?
12-volt batteries supply useful energy only through a limited range — from over 14 volts (when fully charged and unrested) down to 10.5 volts in use/under load (when lights dim, pumps groan and TV pictures get small). No 12-volt battery will remain at over 14 volts for more than seconds unless it’s being charged.
What happens if battery voltage is too high?
Voltage will become dangerously high. The battery can overcharge which will leave it useless. Engine components that aren’t designed to handle the pressure, temperature or power will be damaged. The alternator isn’t designed to handle excessive power and eventually it will burn out.
What causes a car battery to have high voltage?
In order to push energy into the battery, a higher voltage of about 14 volts is created. … Higher than 15 volts indicates a fault in the charging system’s voltage regulator or related circuits. If it’s substantially excessive, this can cause electrical system and/or battery damage.
Can overcharging alternator kill battery?
Other reasons causing overcharging
Bad Alternator: An alternator that’s not providing enough voltage will eventually kill your battery. But it’s also possible for an alternator to overcharge. It may be the wrong alternator has been fitted, or it is providing too much voltage. Both problems can overcharge the battery.
How do I know if my alternator is overcharging?
Symptoms of Your Car Alternator Overcharging:
- Car Battery Voltage Gauge Reading is High. You notice a high voltage reading on your cars vehicle’s dashboard. …
- Car Battery Gets Hot When Charging. …
- Your Headlights Burn Out Quickly. …
- Your Car Battery is Bulging on Sides.
Is 11.9 volts enough to start a car?
The normal voltage needed to start the car begins from 12.6 volts. At the time of exploitation, this parameter is between 13.7 to 14.7 volts.
At what voltage will a car not start?
In general, while both the engine and the generator are in the working state, the voltage of the battery should be within 13.7 – 14.2V. If more, then it is harmful to the battery, if less, then it is not fully recharged.
How much should car battery voltage drop overnight?
How many volts should a car battery lose overnight? When a car drops, for instance, from 12.6 to 12.0, there will be 75% difference. Its power drops from 100% to 25%. At 12.4 volts, a car battery is 75% charged while at 12.2 volts its 50% charged.