What does the battery light mean?


August 21, 2016

What does the battery light mean on my dash?


If the battery light comes on your dash which you are driving, that means there is a problem with the car's charging system. About 90% of the time, the alternator is under or over charging the battery. You probably have less than 15 minutes before the car will stop running.


Can you drive with the battery light on?


You can drive the car with the battery light on but you will only have on average 15 minutes. After roughly 15 minutes, your car will run out of electrical power and the car will stall.


What can you do when the battery light comes on while driving?


Since the vehicle is only running on the power that is remaining in your car's battery, you will want to turn off all electrical components that allow you to still safely operate the car. Depending on the battery condition and the electrical loads on your system, you probably have about 10-20 minutes of driving until your vehicle starts to stall.


I would recommend to get you and your car to a safe place or a local auto repair shop. Also call to get a ride coming for you.


Is it safe to drive with the battery warning light on?


It is not safe to drive with the battery warning light on.


Many things are ran from electricity on the newer cars including some important safety components. Get to a safe spot and find a qualified technician to diagnose the problem.


What items you can I check when the battery light comes on?


If you are able to locate the alternator for your vehicle (which is under the car's hood) there are a few things you can check.


  1. Look at the wires and connectors that go to the alternator and make sure that they are fully plugged in and tight.
  2. Make sure that your engine drive belt(s) is on the pulley of the alternator.
  3. If both of these are okay, you can find a blunt object and bang on the outer case of the alternator while the car is running. (This process is described in more detail below)
Alternator | A+ Japanese Auto Repair, Inc.

Banging on the alternator


Let me describe banging on the alternator in more detail. The blunt object should be wood so you don't short out the electrical system.


You should bang on the thicker outer portion of the alternator, not the center or the fins. You don't want to break the alternator.


And lastly, the car should be running while you do this. What's happening when you bang on the alternator is that you are shaking up the electrical contact points (or brushes) so it's possible that a poor connection could temporarily be fixed. 


You will know if you applied the temporary fix worked if the battery light turns off and you might hear the engine change speed.


If your battery is dead, learn how to properly jumpstart your car.


How long should my car battery last?


The battery warning light comes on intermittently


If the battery warning light turns of and off intermittently, most likely your alternator will fail soon. The alternator's job is produce voltage and amperage to fill up the car's battery and keep the vehicle running. The battery warning light will come on to alert you that the battery voltage is not correct.


(650) 595-2277 or https://aplusjapaneseautorepair.com/


Written by Eric Sevim | A+ Japanese Auto Repair, Inc. | 780 Industrial Rd, San Carlos CA 94070


www.aplusjapaneseautorepair.com | (650) 595-2277

White car | A+ Japanese Auto Repair, Inc.
September 3, 2025
Each car has a different approach to change a spare tire. This is a general procedure to change a flat tire on most cars or trucks.
March 1, 2025
Considering an OEM or aftermarket exhaust? Learn the pros and cons of each to make the best choice for your vehicle. A+ Japanese Auto Repair offers expert guidance and installation for both options in San Carlos, CA.
February 1, 2025
Wondering what that dashboard warning light means? A+ Japanese Auto Repair in San Carlos, CA, breaks down common dashboard lights and how to respond. Schedule your vehicle’s diagnostic today!
October 1, 2024
Does idling your car waste more fuel than restarting it? A+ Japanese Auto Repair in San Carlos explores fuel consumption, environmental impact, and best practices for fuel efficiency.
August 1, 2024
Discover how extreme heat affects your vehicle's interior and exterior. Learn practical tips to protect your car from heat damage, maintain performance, and extend its lifespan. Stay informed and keep your vehicle safe under the sun.
Fueling a car | A+ Japanese Auto Repair, Inc.
May 1, 2024
While providing an exact figure is challenging, most vehicles offer a range of 30 to 50 miles once the gas light illuminates. However, this estimate can fluctuate based on driving conditions, vehicle efficiency, and other variables. For this reason, it’s best to get to a gas station as soon as possible to fuel up.
April 22, 2024
Driving with the A/C does indeed reduce fuel efficiency to some extent. However, by understanding the factors that influence fuel consumption and implementing effective strategies to optimize efficiency, you can mitigate this impact and enjoy both comfort and savings at the pump.
February 1, 2023
Toyota vehicles are known for their reliability and durability. However, even the most reliable cars need regular maintenance to keep them running smoothly.
January 2, 2023
These tiny devices attach to your vehicle’s diagnostic system, allowing you to get the service codes behind warning lights on your dashboard.
August 1, 2022
If you own a Lexus, then you know that it is important to keep up with the required maintenance. Not only will this help your car run smoothly, but it will also help maintain its value. When your Lexus presents a check engine light, the team at A+ Japanese Auto Repair is here to investigate your service codes and maint
Show More