If the motor had just been running and just switched off it should have 14.0V. Left standing with everything off overnight, it will settle down to 12.8V. After a week’s standing it will droop to 12.6V, depending on ambient temperature. After a month it should still have about 12.4 to 12.5V.
Can a car battery drain overnight?
A slow battery drain when everything is off is called a parasitic power loss. … Since the alternator isn’t generating vehicle electricity, the problem component pulls from the battery, slowly draining it overnight until your vehicle won’t start.
What is an acceptable battery drain on a car?
A normal amount of parasitic draw for newer cars is between 50-milliamp to 85-milliamp current draw. A normal amount of parasitic draw for older cars is a reading less than 50-milliamp. Anything past these amounts indicates an electrical issue and should be addressed by a mechanic.
What should car battery voltage be after sitting overnight?
The battery should maintain between 10 and 12.5 volts after a night of not being used. It should have about 10 volts to start the vehicle. Less than that it’s likely the engine will not start.
Why did my car battery drain overnight?
There may be a problem in the starting system. A short circuit may cause excessive current draw and drain your battery. Check the charging system for a loose or worn-out alternator belt, problems in the circuit (loose, disconnected or broken wires), or a failing alternator.
What causes a car battery to go dead overnight?
Some of the most common reasons for a car battery to die repeatedly include loose or corroded battery connections, persistent electrical drains, charging problems, constantly demanding more power than the alternator can provide, and even extreme weather.
How much battery drain is normal?
You don’t need to teach your phone the battery’s capacity by going from full charge to zero, or zero to full. We recommend you occasionally drain your battery to under 10% and then charge it fully overnight.
Is 11.9 volts enough to start a car?
When the voltage of the starting power supply is lower than 11.8V, it will be difficult to start the car. … When the battery voltage is lower than 10.8V, it is generally impossible to start the car. You need to replace the battery or use Jump Starter to start the car in an emergency.
How long should it take to charge a car battery?
Generally, it should take about 1 hour to charge a car battery at 50 amps. However, it may take longer if your charger isn’t compatible with the battery or if there’s some underlying defect with the battery itself. In those instances, it could take up to 5 hours.
How do I stop my car battery from draining?
Ways to prevent your car’s battery from draining
- Keep driving. …
- Avoid short trips. …
- Shut your car properly. …
- Check the battery regularly. …
- Notice warning signs. …
- Keep your car in a garage. …
- Consider investing in a trickle charger.