3 Reasons Why Your Battery Gauge Drops While Driving

Your car battery is an important part of your vehicle that allows it to run properly by providing sufficient power to the engine. The battery gauge shows the health of your battery via meters and lights located on the dashboard. 

So, if the battery gauge drops while driving, you might immediately conclude that the battery has malfunctioned. However, that isn’t always the cause. 

There are several reasons as to why the battery gauge of your car might be malfunctioning like loose connectivity with the alternator, a defective alternator, problems with the alternator belt and the engine, etc. Other reasons include corrosive/rusty connecting wires or wire terminals, and perhaps, a faulty battery. 

Why is it Not Normal For The Battery Gauge To Drop While Driving?

You may tend to rationalize the battery gauge’s drop by thinking that power is being utilized by the radio, lights, and other parts of your car while you drive. So, maybe that is why the battery gauge drops while driving, but, no, that shouldn’t be the case. 

Power is surely being consumed by the battery but it is also supplied to the battery via the alternator while driving. Hence, it is not normal for the battery gauge to drop or even fluctuate while you drive. 

The battery gauge is responsible for indicating the condition of your battery via the meter and lights. And there could be a number of reasons why your battery gauge is dropping when you drive. Find them listed below:

3 Reasons Why Your Battery Gauge Drops While Driving

3 Reasons Why Your Battery Gauge Drops While Driving

#1. Alternator Issue

Your car’s alternator is what converts the mechanical energy generated into electrical energy and running the vehicle with it. So, if your battery gauge is dropping or fluctuating while driving, it indicates that the battery might not be receiving the same amount of charge consistently. 

Car Alternator

This might be due to the alternator not working properly. Probably, the alternator might not be able to convert mechanical energy into electrical energy efficiently or perhaps, it is cutting out or dying midway, etc.

To check if the alternator is working properly or not, you need to take a look at the alternator drive belt first. This belt connects your car’s engine to the alternator and if it is not working properly, then the alternator won’t work properly as well.

Check if the belt is placed tightly enough or not, and if there is some visible damage on it, you should consider changing the alternator belt. The belt needs to be tight enough to transfer the power from the engine to your alternator. 

So, tighten it to the optimum level so that the alternator receives enough energy for its wheel to spin and work. If the belt is fine and tightly placed, then you need to test the car alternator

Connect it to a voltmeter to the battery and the reading should be at 14.4 V without jumping while the car is running. If the reading is any less than this, then, your battery is weak. Else, if the reading jumps, then, the problem is with your alternator.

Solution: If that is the case, then, you need to replace the alternator of your car. Tighten the alternator belt first, to ensure optimum tension for the alternator to receive power from the engine. If the battery gauge still drops, then, check the alternator with a voltmeter reading. You might need to replace it. Go through this article to know how to replace the alternator on your own.

Here’s a YouTube tutorial to help you with the same:

#2. Loose or Corrosive Connections

Loose wire connections can give rise to a flux being formed at the joints. This acts like a resistance that makes it difficult for your car battery to deliver current to the required regions. Moreover, loose connections can also impact the alternator’s efficiency and so, the battery will not receive proper electrical energy. 

Battery Terminal Corrosion

In this case, where the battery terminals can loosen, resulting in flux build-up and subsequent corrosion. Loose or corroded wire connections can result in the battery gauge going down or fluctuating.

Solution: To solve this, you need to undo the battery connections and then clean the terminals of the battery and its connecting wires, especially the ground cables. Then, reattach the connecting wires to the battery.

You have to ensure that the connections are tight and secure so that no flux or corrosion is left at the terminals. Also, before reattaching, use a dielectric grease. If the terminals have corroded, you would need to replace the connecting wires and their terminals.

#3. Car Not Used For A Long Time

If your car usage is infrequent or you haven’t used your car for a long time, then, this type of problem is expected. The engine can fail in this case and all other connected systems can also hamper the working of the car’s battery gauge. 

Perhaps the battery of the car has become old and can’t hold as much charge as it once did. The batteries can lose their ability to hold charges between oppositely charged plates and hence, can’t get charged efficiently. 

Solution: If this is the case, then, you need to get your car checked and fixed by an auto mechanic. Or you can inspect the battery yourself with a voltmeter. Follow this youtube tutorial to know how to do so:

You can say that the car battery is in good condition if its voltage, when it is cold, is in the range of 12.4- to 12.6+. While running, it should be around 14 to 14.6 volts. You might need to replace the car battery or in some cases, proper cleaning of the terminals and removing the rust (if any) can also work.

You should never leave your car unused for long periods of time and take it out on a drive from time to time to ensure such problems never occur in the future.

Final Words

By now, you must have understood what it means if your battery gauge drops while driving. It doesn’t always mean that the battery is bad and needs to be replaced. The reason could be as simple as corrosive or loose wire connections or even some issues with the alternator. 

Try to identify what the problem is with the help of all the reasons given above and then, you can fix it the right way. Your car battery is the fundamental part that allows you to drive the car and you should maintain it properly to ensure that the car runs fine.

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