How to Check If Batteries Are Good
12th September 2022
Whether it is a car, a mobile device, or even a flashlight, it is best you check if the batteries are good before purchase or from time to time. There are many different types of batteries and so is the method to test if they are charged, good, or not.
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The good news is that you can easily check if batteries are good from the way it responds to so many tests and conditions. We have carefully analyzed the differences between a good battery and a bad one and we have outlined some steps on how to check if batteries are good.
How to Check If Batteries Are Good
- You can check if a battery is good by a simple drop test. Simply hold the battery vertically about 2–3 inches above a hard, flat surface. A bad battery tends to bounce more due to the presence of zinc oxide which builds up inside alkaline batteries.
This test differentiates an old battery from a new one as a fresh battery will plop down without bouncing. It may roll over onto its side but won’t bounce back up. On the other hand, an older battery will bounce up several times before falling over.
- Use of Voltmeter
A voltmeter gives a more accurate test for a battery charge. To test using a voltmeter, you need to locate the positive and negative terminals of the battery. These points are located on the battery as (+) and (-) for alkaline and rechargeable lithium batteries. On AA, AAA, C, and D batteries, the negative terminal is the flat side and the positive side has a protrusion. On a 9v, the smaller, rounded terminal is positive and the larger, hexagon terminal is negative.
Voltmeters measure alternating current and direct current. All batteries use direct current, or DC so ensure you turn the knob on the front of your voltmeter to DC before taking a reading.
On a voltmeter, the red lead is the positive one. Hold the positive lead to the positive battery terminal and the negative lead to the negative terminal.
Be careful to place the terminals correctly to avoid a wrong reading. Hold the leads to the battery to get the volt reading. The meter will produce a reading within a few seconds. Use this reading to tell if the battery is fresh or not. Fully-charged AA, AAA, C, and D batteries have a charge of 1.5 volts. A 9v has 9 volts. If the charge is more than 1 volt below where it should be, then replace the battery.
- Battery Testers
Battery testers are easier to use than multimeter and voltmeter. You can use the readings to check if the batteries are good. To do this, place the battery and take a simple reading. The testers have a slide that moves back and forth to adjust to different battery sizes.
- Test For Car Batteries
You can check if your car batteries are good from the sound when you start the car starts. If the batteries are bad, you will not get cranking at all from your engine and your headlights won’t come on and even if they do, they will be very weak. If your battery is almost dead, the car may crank some but won’t actually start. Another method used to test car batteries is to use a multimeter or voltmeter. To do this, ensure that you turn the car off first. Then, lift the hood connecting the batteries to the car and look for a black rectangular box marked with positive (red) and negative (black) terminals. Using the voltmeter or multimeter, place the end of the black probe on the negative terminal and the end of the red probe on the positive terminal and then take the readings on the device.
If your battery is reading at or above 12.45 volts, your battery is still in good shape, therefore the problem isn’t from the battery. However, if your battery is reading below that, it won’t consistently start your car, and you’ll likely need to get a new one.
- Test For Phone Batteries
To check an iPhone battery, you can use the Apple Support App. Download the app from the Apple store and start a chat with one of the technicians, who will walk you through how to run a diagnostic on your battery. The diagnostic report is sent to the technician, and they’ll be able to tell you how healthy your battery is. You can then check from the phone “Settings”, then Privacy, and finally Analytics. Check if “Share iPhone Analytics” is checked. If not, press on it to enable the tech to view your analytics reports. Also, use a third-party app to test an Android battery. Download any of the app testing batteries, like AccuBattery. Open the app and follow the instructions on the screen to set it up. Then use your phone as you normally would for at least a day. After a day, open the app to view information on the health of your battery. You’ll get more accurate information after using the app for weeks or even months.