What Is Service Battery Charging System & How To Fix It? (2024)

Your vehicle’s electrical system is as important as the fuel, lubrication, and coolant flowing through the engine. Think of the electrical system as the brain of the car, which tells the rest of the parts what to do.

What Does Battery Charging System Mean?

The electrical system of your car works like this:

1. The battery turns the starter, which fires the engine via the spark plugs.
2. The alternator receives power through a belt from the action of the engine working.
3. The alternator turns the engine’s power into an electrical current that recharges the battery.

If anything interrupts the flow of power to the engine, it won’t run very long, and a battery light will likely be illuminated on the car dashboard. An OBD tool can be used to diagnose the source of the problem by plugging it into the car’s onboard computer.

What Causes Battery Light to Come On?

Symptoms that your battery charging system is failing include:

• Dim headlights.
• Trouble starting the engine.
• Accessories are not charging when plugged into USB ports.
• Failing accessory electricals like stereo, interior lights, and heater fan.

If your car alternator is not supplying power to the battery to recharge, the battery will eventually stop working. How long that takes depends on the age and condition of the battery.

It’s common for a battery to last three to five years, but many factors play into that lifespan, including the age of the battery when you purchased it. Your driving habits and the weather and dry or wet conditions in your area can affect that lifespan significantly. Your battery will last longer if:

• You minimize its exposure to extreme temperatures: hot summers and cold winters wear a battery down.
• Onboard accessories are not overwhelming the system. The more you use Bluetooth, keyless door locks, DVD players, electric seats, and charging ports, the faster your battery will be depleted.
• You take longer drives at higher RPMs, which will recharge the battery because short drives at low speeds do not.
• You drive long distances frequently. Leaving a car parked for weeks at a time drains the battery because systems like the keyless entry, security system, and onboard computer are always on, using electricity from the battery that isn’t replenished as long as the vehicle sits unused. Tip: if you’re going away, consider taking the battery cables off the terminals during that time so the battery isn’t drained by automatic systems like door locks and thermometers.
• The manufacturer and retailer took proper care of the battery before you purchased it, including providing a battery that wasn’t old when it was installed in your vehicle.
  

How to Fix Battery Charging System

If you get a sensor reading that says “service battery charging system,” there are several options to pursue. You can:

• Check the main battery and remove corrosion at the terminals so there’s a clean connection. This can be done with a cleaning solution from an auto parts store. Remove the wires from the battery terminals and scrub off any rust or corrosion. Allow it to dry before reconnecting.
• Get your battery tested at an auto parts store. They can tell you how much of its lifecycle has been depleted and how long it is likely to last. They can also test the alternator to determine if it’s sending sufficient charge to the battery.
• Check for stray voltage. A loose component within the electrical system could be malfunctioning and drawing down power.
• Make sure your battery is securely fastened in place. A loose battery that rattles around won’t maintain good connections, nor will it last as long as a secured battery.
• Check your battery for general wear and damage. In cold climates, road salt can get inside the engine and cause issues with the battery wires and the container itself.
• The starter is a major draw on battery charging system power. If your starter is going bad it could deplete the battery through stray voltage or the driver’s needing to crank the ignition many times to get the vehicle started. You can use a voltmeter to find out how much power the starter is drawing and whether it is effective.
• If the battery seems okay but the engine won’t start, check the fuses. One blown fuse can affect the vehicle’s ability to send enough charge to the starter.

Usually, when the “check battery light” comes on, it means there’s something wrong with the alternator. The alternator is an important electrical system component that should be checked for proper function on a regular basis. Because it sends power back to the battery to recharge it when the vehicle is running, an alternator that isn’t working or has bad connections can be the culprit behind a check battery light. Check the following:

• The alternator’s electrical connections for disconnection or corrosion. Disconnect the vehicle battery before moving the wiring if using a commercial connection cleaning spray. Take apart any wiring harnesses on the alternator and spray the cleaner inside, allowing them time to dry before reconnecting. Also, check wires for wear and any breaks.

• The alternator’s drive belt, around the lower engine crank pulley, should be checked to ensure it’s in place and in good condition. If there’s a whining or screeching sound from the engine when it’s running, it could be this belt slipping from wear or improper tensioning. It may not deliver consistent power to the alternator if it is not securely wrapped around the proper pulleys and tightened correctly. If in doubt, replace the belt.
• Another indication that the alternator belt is problematic is if your coolant system is not running properly. The coolant pump is operated by the alternator belt. If the coolant system is not working, your vehicle’s temperature sensor is likely to be triggered by a high engine temperature reading.

If the battery is relatively new but is getting drained and the alternator checks out okay, you have to find out what else could be using the battery’s power. There can be a bad sensor somewhere in the vehicle that is drawing power. Something like automatically closing doors that do not have a good connection may still open when they appear closed, which draws electricity even when the car is off. Chasing down these possibilities is imperative because even a new battery won’t last long withsuch continuous, unnoticed drainage.

Use an OBD Tool to Diagnose

An OBD tool is a scanner used by auto workshops and mechanics to diagnose engine problems. It uses the onboard computer technology to decipher messages from sensors throughout the vehicle – and some cars have hundreds of sensors.

Battery charging systems are typical sources of problems with vehicles not starting or functioning as they should. A newer battery without corrosion may not be able to keep a vehicle running if the alternator has loose wiring or the belt to the crankcase is loose. Likewise, fuses and a vehicle’s many ports for power all play a part in keeping an engine performing properly. Some are issues that a novice can identify and repair, like installing a new battery, but others are too involved for the average weekend mechanic to do alone.

Simply plug in the OBD tool to the outlet that’s usually located near or under the steering wheel. Turn your ignition key to “on” without starting the engine. If the scanner doesn’t make a connection with the car’s computer, try plugging something into the car’s “lighter” port to see if that works. If neither is getting power, you may need to borrow a fully-charged battery to begin the process.

Follow instructions for receiving sensor messages. It may require you to input your vehicle’s VIN number, which is found on a small plate in the corner of the windshield or inside the frame of the driver’s door.

The OBD tool receives information in five-digit codes. Each of the digits represents a significant piece of information:

1. The first digit is the location of the problem, such as P for the powertrain or U for the onboard computer system.
2. The second digit tells you if the issue is specific to the manufacturer or generic.
3. The third digit provides more specific information about the location and nature of the issue with your vehicle. You’ll want to find a key to the codes that are specific to the make, model, and year of your car to determine if the problem is something you can tackle or if you need to take the car to a mechanic.

Modern vehicles have complex electrical systems with dozens to hundreds of sensors that feed information to an onboard computer. When that system is deprived of electricity due to an old battery, faulty connections, malfunctioning alternator, or simple corrosion, you must track down the culprit and rectify the problem before you end up stranded with a vehicle that won’t start. It’s key to take action and start testing systems the first time the check battery light comes on. You’ll be glad you did.