You are driving down the highway, and you notice all of your lights are starting to fade. Knowing that the alternator of your vehicle is beginning to fail from the symptoms the car is showing. How long can you drive a car with a bad alternator?
The answer is as long as your battery has power still stored. Once your alternator has stopped working, your vehicle starts to take the energy it needs from the vehicle’s battery. Without your alternator to recharge the power taken from the battery, it is only a matter of time before the battery has no more energy to give the car to operate.
A great tip to increase the time and power that your battery has. That is to shut off any unnecessary functions in the vehicle that are not needed to operate the car.
A great example would be your air conditioner and radio. Disabling these functions will give you a little bit more time to get somewhere safe to park the vehicle. What else can help you with your alternator problem? Let’s dig in deeper and see what you can do to prevent being stranded with a bad alternator and dead battery.
What will my car do if my alternator is bad?
I remember in High School I had this 1989 Honda CRX Si, and I loved that vehicle. It was small and quick and maybe sometimes too fast. Well, I was on my way to work when, of course, I was speeding. As the police officer
pulled up behind me, my headlights started to flicker.
As soon as I saw that I forgot all about being pulled over, I knew the day was about to get a lot longer. I shut off the engine as quickly as possible to save as much power in the battery as possible.
There is no need to waste the amount of juice I have left while I am getting a ticket. Thankfully I had enough power still in the battery after getting my ticket to make it to town to park the vehicle before the battery ran dead.
So the first sign of a failing alternator is flickering headlights. Strange sounds and a dead battery are two more signs that your alternator is failing. The peculiar sounds would be whining and grinding coming from the alternator.
When an alternator is failing, it can be an array of causes, but the grinding would be because of a worn or damaged internal bearing. The whining would be caused by the voltage regulator on the alternator requesting more voltage than the alternator can provide.
One of the most prominent indications that you will notice very quickly is failing electronics. When your alternator is failing, it cannot give the power that your vehicle requires. When this happens, all electronics in the car will start to slow down.
The power windows will work slower, the radio can flicker on and off, and other electronics, if they power on at all, will not operate correctly if they stay on at all. Diagnosing and replacing your alternator is vital to the operation of your vehicle.
In newer vehicles, the electronic system can be fatal to the car in general. So make sure you diagnose the problem quickly so you can get the car repaired and be back on the road.
Can I jump start my battery with a bad alternator?
Yes, you can jumpstart a battery even if the alternator is bad. When you jumpstart a vehicle, you are adding voltage instantly back into your battery. Once you remove the jumper cables from the vehicle with the lousy alternator, you start a countdown.
This countdown is counting down the time you have until the battery is dead again. Your alternator is bad, so your car will be drawing it’s needed power from the battery. The vehicle will continue drawing power until the battery is dead again.
Do I need to replace my battery if I replace my alternator?
Yes, it would be suggested that you replace your battery if you run the voltage down to zero. The alternator can charge car batteries but having your alternator charge a completely dead battery is bad for your alternator.
If you wanted to try to keep the battery, you still have instead of investing in a newer battery. There is a way you could save it, and that is by using a trickle charger. A trickle charger is a battery charger that is capable of completing a deep cycle charge on car batteries.
This type of charge is a low voltage for an extended period. As the charger slowly charges the battery back to operational voltage, this will ensure the battery holds it’s durability in the lead plates. By doing this, you are not giving your battery shell shock by giving it a fast high voltage charge.
Why did my alternator stop working?
Your alternator has a voltage regulator, magnets, and connectors. An alternator is vital to your vehicle, but just like a part is destined to fail over time. Alternators’ internal parts can get worn and torn over time and start to deteriorate, causing your vehicle to fail as well.
Usually, internal alternator bearings will go out, and once this happens, the 
alternator will stop working. To keep your bearings in great shape, make sure you keep your serpentine belt at the correct tension.
There is nothing else that will kill your bearing quicker than an over-tightened or under tightened serpentine belt. This will put extra strain on the bearing, causing it to fail early. If your alternator does not have an output of at least 13.8 volts, then it needs to be replaced.
If your alternator has an output of over 15 volts, then it needs to be replaced for overcharging. Alternators do not respond great to water, heat, oil, and dust. So if you have a leak, make sure you repair it promptly. If you have dust and dirt accumulating on your alternator, use some compressed air to clean it off.
Do not spray your alternator with water and cleaning solvents, and these will cause wear to your internal brushes. As long as you keep your alternator maintained, then you will have a reliable vehicle for years to come.
How can I prevent my alternator from failing in the future?
To prevent your alternator from failing in the future, you need to add it to your scheduled maintenance interval.
By keeping a lookout for any of these symptoms. You will be able to notice when your alternator is going to fail. Also by checking your battery and alternator with your code reader if it has that capability will save you some time as well.
My Zurich ZR11 can run tests on my battery and alternator while they are still installed in the vehicle. That saves me a lot of time from needing to remove the parts to take them somewhere to be tested. It even saves me time from needing to drive anywhere to test it at all. So if you do not have these tools, you need to pick it up to add to your tool collection.
You can use a load tester on your battery to check it as well. If the load tester says you have a low charge, hook the battery up to your car charger then test it again after a charge cycle has completed. If you have a large stereo or multiple accessories added to your vehicle, upgrading the alternator to a higher voltage output would prevent additional strain on your car.
Many things can be taken into consideration when modifying your vehicle. But remembering that your alternator and battery are the show starters and show stoppers if not properly maintained is a valuable lesson.
Thank you for reading my article! I hope you found it beneficial and enjoyable to read! Check out my Youtube channel and subscribe for more DIY Auto Repair and flipping cars for profit videos! Thank you again, and I hope you enjoy my next piece!
