Ways to Read The Amp Meter of a Battery Charger 

 September 19, 2021

By  Phil Borges

In order to have a better understanding of the battery charger, it is important to take some time and read the amp meter.

Most people don't know how to read their car battery charger amp meter, so this article is created as a guide for you. Read on and find out more how to read a battery charger amp meter.

How does the battery amp meter work?

The amp meter tells you how many amps the battery storage system is consuming at a given time. If the amp meter reads zero, then this means that there are no batteries in the battery charger.

A battery charger amp meter can be a handy tool when maintaining your vehicle's battery - not to mention the peace of mind that comes from knowing exactly what's going on.

Maintenance of the vehicle battery is important to avoid damaging the battery and prevent the cause of serious problems as given below:

  1. Aging or breaking down (batteries lose their ability to hold a full charge).
  2. Swollen cells (cells swell when they are not fully charged)
  3. Corrosion (this will happen when you store your vehicle for an extended time with older batteries.)

Guides to connecting the battery charger

Guide #1: Ensure that all of the terminals on both ends are clean as possible. If they're not, scrub with a wire brush until you get them shiny again.

Guide #2: Next up is safety! Always do this in an open area that has plenty of ventilation so there's less chance for any gas buildup from leaking hydrogen acid fumes.

Guide #3: Wear gloves and some eye protection while working on anything involving batteries because their contents can be dangerous if spilled onto skin or eyes.

Guide #4: Turn off everything when it comes to actually charging-including interior lights and radios.

Guide #5: Always make sure to identify terminals of the battery.

Guide #6: Carefully connect the red cable to the red battery terminal (positive).

Guide #7: Protect yourself from sparking batteries when connecting the black terminal (negative).

Guide #8: And lastly, switch on the charger and allow the amp meter to work for you!

How to read the amp meter of a battery charger by knowing its parts?

  • Check the charge rate. When you charge your battery, the amps are tracked in order to make sure it's charging at a fair and safe rate.
  • The amp scale will display how charged your battery is. As the voltage of your electric charge increases, so does the level on this needle. This gauge shows a reduction in amps as you're at full power and an increase when you run out of juice!

What to expect if a battery charger is working

The moment the charger gets connected and switched on, it will immediately show an indicator of how much electricity is flowing. The needle moves to the sharp right and after a few seconds it will move to the left, then congratulations! Your battery has been charged.

Output when battery charger gets fully charged

The battery charger needle jumping will show around half the input setting you selected when the battery is full.

On a 12 amp charging setting, the needle will settle at 6 amps or under and on 2 amperes it settles near to red triangle end of a small one.

Some problems that may encounter when reading a battery charger gauge

Jumping needle:

If the battery charger needle is jumping, this may be a sign that your connection to it isn't great.

If the clips are not making contact with the terminals on your car's battery, this can happen. It may be caused by a defective or discharged cell in the battery itself.

Needle not jumping:

You may be experiencing a charger fault if the needle on your amp meter does not move. If this is the case, connect it to another battery and check for any difference in reading. The same result shown will mean damage to the charger.


If your battery charger has an amp meter, make sure you take a minute to look at it!

You may be wondering why you should care about the amp meter on a battery charger. The reason is simple - it’s good to know how much charge your batteries have in them so that you can avoid overcharging or undercharging them, which decreases their life span and causes more frequent replacements.

We hope this guide helped you understand how to read an amp meter for voltage and current levels as well as what they mean when reading them. 

About the author

Hi, I'm Phil Borges.. thanks for reading.. My wife says I can't shut up about batteries so to save my marriage I've started this blog .. where I'd be ranting about batteries! Please leave a comment if you have any questions, I'm happy to help!

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}
Battery Tools