For AA, AAA, C, and D batteries, hold the battery so the positive side faces up. For a 9v battery, hold it so both nodes face up and the flat end faces down. A wooden surface is not the best choice for this test. Wood absorbs more energy and items don’t bounce as well.

Remember that if the battery bounces, this doesn’t mean it’s dead. It just means it’s older and is starting to lose its charge. [3] X Trustworthy Source Princeton University Leading academic institution devoted to expanding and sharing knowledge Go to source This is a handy test if your batteries are all mixed up and you can’t tell which ones are fresher.

Since the battery is dead, it will bounce higher than a fresh one. Compare the two bounces to determine the specific condition of the battery you’re testing.

This method works 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. Lithium batteries come in many shapes, so look for the markings on the battery to determine its positive and negative terminals. You can also use a multimeter for this test, but make sure you set it to measure in volts rather than amps or ohms.

Some voltmeters require you to pick a max level for the current you’re testing. On most, the lowest setting is 20 volts. This is enough for all common batteries, so set the meter to 20 volts if it requires you to pick a level.

If you mix up the leads, it won’t damage the battery. But the reading will be in a negative value rather than a positive one. Common household batteries won’t shock you during this test, so don’t worry.

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. A normal charge for lithium ion batteries is 3. 7 volts, but this could vary. Check with the manufacturer for the full charge. A 3. 7-volt lithium battery usually stops working at 3. 4 volts, so recharge or replace your battery if it s approaching this level.

A fresh 1. 5V battery will read 4 milliamps, and a fresh 9V measures 25. Readings below this indicate a dead battery. At 1. 2-1. 3V is typically when most 1. 5V batteries start to become weak. This particular test won’t work on a lithium ion battery because multimeters don’t have load test settings for their voltages.

To test a 9v, some meters have a separate port to touch the battery against for a reading. Check your meter to see if it has this feature. Some meters can also test lithium ion batteries if they’re shaped like standard alkaline batteries, but not if they’re irregularly shaped.

If your battery is almost dead, the car may crank some but won’t actually start. While that’s not always the battery, typically it is.

Your battery may be covered with a plastic hood. If it is, refer to your owner’s manual. You’ll likely need to unscrew a few screws to take it off.

If your battery is reading at or above 12. 45 volts, your battery is still in good shape, and any problems you may be having are likely caused by something else. If your battery is reading below that, it won’t consistently start your car, and you’ll likely need to get a new one. A car battery tester will do the same job. All you need to do is place the black clip on the negative terminal and the red clip on the positive terminal.

This is the easiest and the most accurate way to check your car battery. Most auto parts stores will even put in a new battery for you if you don’t know how to do it. If your battery is dead, you can jump it or charge it to get to the store.

Typically, you’ll need to go into 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.

You can also use third-party apps, such as Coconut Battery, to test an iPhone, but you’ll need to plug it into a Mac to do it. [17] X Research source

These stores can also replace your battery if it’s gone bad. They may need to wait for the part to arrive if it isn’t in stock.