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What you need to test a car battery

Testing a car battery

If your car is having frequent battery issues, you may be wondering why. While the reasons for your battery going flat are often simple, they can sometimes be complex. This is why most vehicle experts recommend testing your battery on a routine basis. 

What's more, a common complaint after recharging a battery or having it restarted by jump leads is that it goes flat the very next day. This can cause you to miss the school run or even miss essential events or engagements. Regularly testing your car battery, especially after a jumpstart, can avoid lots of hassle down the line.

How does a car battery work? 

Batteries function by converting chemical energy into electricity. They do this by converting actual energy in the battery cells into electrical energy when commanded to do so. 

Car batteries work using acid and lead. First, when you turn the key in the ignition, the battery powers up the engine's starter. Next, when the engine is running, the alternator is put into action. The alternator is then used to recharge to charge the battery while the car is running. This process for recharging your battery is the reason your car battery may become flat if you don’t drive your car for a long time.

There are some common indicators you can look out for to see if your car battery needs testing. This includes dimmer headlamps on the car, a smell of bad eggs, increased time for ignition and noticing signs of corrosion or damage directly on the battery itself.

What you need to test a car battery

An effective and efficient car battery testing kit is essential in any car emergency kit or maintenance set. This is because batteries like engines don't stop working in the most convenient places or at the most convenient times. 

Plus, if you live in a remote location or do long drives, you may need an effective set of jump leads or the capability to identify the problem and fix it by recharging the battery on the spot without the help of another car battery. Depending on your needs, you may opt for a multimeter, battery analyzer, smart charger or even a refractometer. 


Multimeters are primarily used to check the voltage of car batteries. While this might be great for checks on whether or not the battery is entirely dead, it does not speak to other underlying causes of battery failure. This means that things like battery acid levels are not measured with the multimeter. 

Multimeters work by applying the probes to the terminals of the car battery. This should be done while the battery is resting. A healthy reading should be in the range of 12.2-12.6 volts. Readings above or below the stated levels may indicate other issues in the battery.

Battery analyzer

A battery analyzer plugs onto your battery and tells you about multiple aspects of the battery’s health. This includes battery condition, charge and alternator. Some models will even give you data on the starting function of your battery. 

Most battery analyzer models are powered by lithium batteries, so you don’t need to worry about charging them too regularly. What's more, the overall battery data is an unbeatable option. This is because most good battery analyzers will check AMH and AH capacity. Some even offer advice on whether or not you should simply recharge the car battery or replace it altogether.

Smart charger

Smart chargers are great for users who experience frequent battery issues. This is because while most batteries will go after one or more charges, never to go flat again, some give up on you at the worst possible time. 

With a smart charger, you have a device that can analyze, charge and, in some cases, even repair your battery. One particularly notable feature of smart chargers is their ability to remove sulphur buildup from your car battery, improving its functionality and extending its lifespan. The functionality of smart chargers ensures you won’t waste time or money recharging or repairing a battery that simply needs replacing.

Smart chargers can sometimes come with powerful batteries, but more than often, they come with plugs for in-wall access. 


You can use a refractometer to check the battery acid levels on your car battery. This is a great way to find out where the battery charge level is compared to where it should be. To use a refractometer, you first need to make sure that you have hand and eye protection in place, such as thick gloves and safety goggles. 

Next, you need to remove the vent covers off the battery with a screwdriver. Next, it's time to test the battery electrolyte, coolant freezing point and adbule levels in the battery. You first need to calibrate the machine to the levels stipulated in the instructions. Next, apply the refractometer to the battery and check the levels, which should be in the guide that comes with your refractometer.

What you need to buy to test a car battery

600V Auto-Ranging Digital Multimeter

This handy multimeter is super easy to use, and provides indicators on AC/DC voltage and temperature. It’s a quick and simple way to test your car battery functionality and health.

Where to buy: Sold by Amazon and Home Depot

NOCO GENIUS10 10-Amp Fully-Automatic Smart Charger

This smart charger is a full solution for battery testing, maintenance and repair. It can charge fully dead batteries, restore your battery life and detect problems such as sulfation on your battery. Overall, this smart charger provides stronger performance for engine starting and increases the lifespan of your car battery.

Where to buy: Sold by Amazon and Home Depot

Aichose 4-in-1 Refractometer for Automobile

This handy little tool provides four refractometer functionalities, including testing the gravity of your car battery acid and the general condition of your battery charge. But it also helps you with other general car maintenance checks such as measuring the freezing point of your antifreeze.

Where to buy: Sold by Amazon 


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Lauren Farrell writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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