If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. If a jump starts and keeps your car running, but the car can't start again off of its own power, a dead battery is probably your answer.
But when the engine is off, the alternator can't recharge the battery, allowing little electrical mishaps to drain your battery entirely. The battery strain caused by these electrical whoopsies is known as a parasitic draw.
If you find code P0562, you very likely have a failing alternator (note that codes may vary by vehicle make/model/year). Get it checked out before it fails entirely. If you suspect a failing alternator but don't have a warning light, pop the hood and check the condition of the belt.
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.
“Electrical devices or lights left running, a defective charging system or alternator, and extreme weather are some common reasons but maybe it's just time to get a new battery.”
What Causes a Car Battery to Keep Dying? 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.
No a burnt fuse can't cause battery drain issues. Some fuses don't get power until the circuit is turned on so don't be concerned about them. Has your battery been replaced or load tested to make sure it's good? A weak battery can make it seem like you have a draw.
You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.
The answer is simple - Yes, You can jump-start a car with a bad alternator.
The most common causes of excessive parasitic drain include faulty relay switches, malfunctioning alternators, damaged wiring or connections, and electronic devices left connected or powered on when the vehicle is off.
Mechanics uses a computerized charging system tester to check your alternator. This is called an AVR test, and it can show if there's a weakness in the charging system, or if you'll need to repair or replace your alternator.
Alternators can go bad suddenly, or slowly over time. If your alternator is slowly going bad over time there are some warning signs you can look out for.
One of the most common problems you're likely to experience with an alternator is a failure in the bearings. There are needle bearings in the alternator that allow the rotor to freely spin inside the housing, and those bearings can break down over time as a result of exposure to heat and dirt.
Make sure your alternator's positive and negative terminals are clean. Put the multimeter's black cable to the negative terminal and the red cable to the positive terminal. Look for an ideal alternator reading of around 12.6. Start the car, and look for a reading of between 14.2 and 14.7.
The alternator translates the mechanical energy generated by the car into potential energy for the battery to store—like a charger for your car's battery. If the alternator is kaput, the battery in the car will soon follow and can stall the car.
“If the [battery's] voltage is low, replace with a new battery or charge the battery to the recommended 14.2 to 14.7 volts,” he says. “Then try to run the vehicle and see if the voltage after is outside of that range. If it is, that's a sign of a bad alternator.”
Your battery should be one of the first things on your checklist after installing a new car alternator. Any installation guide will say that you need to disconnect the battery before installing the new alternator. So, at the very least, you need to make sure that you reconnect it.
Most alternators will last between 80,000 and 150,000 miles — or about seven years. However, your driving habits and the area where you live could wear it out prematurely.