How much should a 12v battery discharge?
The lifespan of your battery will be moderately affected if it remains within this voltage range for extended periods of time. 12.0 volts or below – At 12.0 volts your battery is considered to be fully discharged or ‘flat’ and should be recharged as soon as possible.
What should a 12 volt battery be at rest?
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.
How long does it take for a 12v battery to discharge?
New Car Batteries A new and fully car battery can stay for around two weeks without needing to be recharged from a generator. This battery will fully get discharged after approximately two to three months. If you leave the battery for roughly two and a half months, you will not be able to start the car engine.
How do I know if my 12-volt battery is bad?
There are some sure ways you can tell if your battery is bad by simply taking a good look. There are a few things to inspect, such as: a broken terminal, bulge or bump in the case, crack or rupture of the case, excessive leaking, and discoloration. Broken or loose terminals are dangerous, and can cause a short circuit.
What voltage is too low for a 12 volt car battery?
No 12-volt battery will remain at over 14 volts for more than seconds unless it’s being charged. The lowest limit is 10.5 volts (used in testing) and obviously unsatisfactory in practical use.
How do you discharge a 12 volt battery?
Specifically, if you want to fully discharge a typical car battery (12V, 60 A hr), all you need is a 20 ohm, 10 W resistor (or equivalent), and connect it across the battery terminals. Leave it connected for about 4 days, and with a voltmeter verify that the voltage is zero. Since the current is only (12/20 =)
What causes a car battery to drain in the morning?
If your alternator has a bad diode, your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won’t start. 5. Extreme Temperature
Why does my car battery discharge after charging?
It’s possible you have problems with the battery itself (see the “state of charge” table below). Charge the battery and repeat the test. If you get the same readings (and problems) after charging the battery, you may want to take the battery to a shop for a battery load test. This is one of the best ways to confirm battery condition.
Can a bad alternator drain a car battery?
A car alternator recharges the battery and powers certain electrical systems like lights, radio, air-conditioning, and automatic windows. If your alternator has a bad diode, your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won’t start.
Can a car battery go dead from sitting?
If you expect your car battery to sit unused for more than a month, you should consider removing the battery and storing it away. Always store your battery at full charge. This will help prevent most damage and deterioration that can happen while in storage.