Battery Charger Needles Goes Up & Down/Back & Forth (Fixed)

diehard, schumacher battery charger needle jumping up and down, bouncing, back and forth

Sooner than later, you will have to charge your car’s battery. The more miles you cover, the faster this will happen. While in most cases, charging your car’s battery is a straightforward procedure, you often might encounter a problem. One such problem is the battery charger needle moving back and forth.

Why is my battery charger needle keeps jumping?

The battery charger needle keeps jumping because of a shorted cell, short in the charging system, internal overload, excessive drain current and faulty connectors.

1. Shorted cell:

The charger needle denotes the current being supplied to the car battery. Ideally, it should move from right to left as the car battery charges more and more. If it kept jumping right and left, it might indicate that something is providing erroneous reading to the charger. Therefore it is sometimes providing higher current and sometimes lower current.

Any shorted component in the circuit can keep the needle jumping around.

It is the most common cause.

2. Short in the charging system:

Not always, the problem is with the car battery. Many times, the problem can be with the battery charger as well. In that case, the battery needle might keep on jumping as well.

In this case, all the components and the systems of your car ride in perfect shape. The problem is only with the battery charger.

3. Excessive drain current:

The charger needle monitors the amount of current being supplied to the battery. If there is a drain current, the current provided will be irregular. Due to this irregular drain current, the charger needle might keep on jumping.

The problem is that drain current just leads to loss. It will not charge the car battery either.

4. Internal overload:

It is essential to match the specifications of the battery charger and the car battery. When the specifications match, you can use that charger to charge the car battery.

If the amount of current needed by the car battery is much higher than what the battery charger supplies, it will suffer from an internal overload.

When this occurs, time and again, the car battery charger will try to supply a higher amount of current but will fail to do so. That is why; the needle will keep on moving back and forth.

5. Faulty connectors:

In very rare cases, the connectors are faulty. This specifically refers to the terminals. In case the connectors are rusty, the current will not be appropriately supplied to the car battery.

If you want to make sure that this is indeed the problem, just take a look at the shape and condition of the connectors. If it is deformed, the connectors might be the problem. On the other hand, if the connector alligator clips are covered in rust, the charger needle might keep on jumping because of the same.

Related post: 5 Reasons Car Negative Battery Cable Getting Hot (Fixed)

What does the needle mean on a battery charger?

The needle of the battery indicates the amount of current being supplied by the battery charger to the car battery. Usually, when you turn on the charger, the needle is on the right inside, indicating that a high amount of current is being supplied. As the car battery gets charged more and more, the needle moves from right to left.

If the battery charger needle keeps jumping, it indicates that the current level being supplied to the car battery also varies. That is not how it should be.

Is it safe to charge my battery if the needle keeps jumping?

Only if the charger does not trip when charging the car battery should you continue to charge the battery. Otherwise, it is better to disconnect it from the car battery.

How long should you charge a car battery when the needle jumps back and forth?

You should continue to charge the car battery when the needle is jumping back and forth until the charger trips. If it starts tripping every time you connect it, you should immediately stop charging the car battery.

How can I fix a battery charger needle that keeps jumping up and down?

1. Replace the battery

Unfortunately, when the battery is short itself, there is no solution to it. You either have the option to continue with the same battery with less charge, or you will have to replace the battery itself.

In most cases, however, if a battery is short itself, you will have to replace it sooner than later.

2. Replace the charger

Many times, the problem is with the charging system itself. When that is the case, the needle might jump, and the charger might shut down due to short circuit protection.

You have to simply charge the battery with another car charger to test this. In case it works pretty well, it indicates that the older battery charger was the problem. The solution is equally simple as well. You will have to replace it. Even if it means buying a completely new one, you have no other choice.

3. Ask the mechanic

In case of excessive drain current, there might be a problem with one of the components. The problem can be with the component of your car or charger. Only a trained mechanic can identify the exact problem.

4. Check the battery specification and use the matching charger

If, after needle jumping, the charger trips, it is an indication that the car charger might suffer from overload. In that case, you have to carefully check the battery specifications and opt for another charger that matches the specifications. That is the easiest way to solve this problem.

5. Change the alligator clips

This problem is the easiest to solve. You have to just buy new connectors. In case the alligator clips are straight, merely changing the alligator clips will solve the problem.

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