The Best Car Battery Tester

Topdon's BT100 is the top-rated product in the category and replaces the former #2 pick AB101 on our list. It works with all major battery technologies: Conventional and enhanced flooded (EFB); AGM flat plate; AGM spiral; and gel. It can perform a standard battery health test (shown), cranking, and ripple charging system test. You get both a backlit illuminated 128 x 64 LCD readout and green-yellow-red warning lights.

Testing the BT100 Car Battery Tester

We hooked up a BT100 Car Battery Tester to one of our Optima Yellow Top test batteries (note: you must connect it directly to the posts), and the display came on immediately. The opening screen shows a small voltage readout at the bottom, and then you have to select your battery technology, in this case, AGM spiral wound, from the following screen. During several rounds of testing, we noticed that the display gets sluggish in colder temperatures. Getting a battery health reading was easy. We then tried the cranking and charging system health functions in a Mazda with a flat-plate AC Delco Gold battery. The battery health ripple test requires starting the car and holding the RPM at 2,500 for five seconds, which would be a lot easier with two people. But it was possible and gave us useful information (including that wherever our short is, it's not in the charging system). Our biggest complaint is that it must be connected to a battery for the display to work. With short leads, this could be inconvenient for trunk-mounted batteries. It's a great battery tester for occasional use, but if we were using one a few times a week, we'd want to upgrade to either a printout or Bluetooth. We would also have liked a case or at least a storage bag with it.

The BT100 has a great 92% positive rating from over 2,000 reviews, the best weighted average in the category. Topdon's other models of battery testers have similar 90%-plus ratings.

Topdon Warranty and Customer Service

There is a good two-year limited warranty on Topdon battery testers and a brief three-day money-back guarantee on defective items. The company also offers a loaner tool program if your tool requires repairs under warranty. There is a toll-free customer service number for Topdon's New Jersey headquarters and a number of web forms for technical support and warranty issues. We found high-quality pdfs of user manuals as well.

One of the most popular and highest-rated products on Amazon in this category is the Innova Battery and Charging System Monitor. It's an extremely easy-to-use device, because it plugs straight into your cigarette lighter to monitor battery and charging system voltage. It's designed for 12-volt negative ground systems and features an LCD display with a bar graph to indicate charge level. There are also color-coded LEDs so you can quickly identify your battery's charge status. The head of this device pivots so you can easily adjust its angle for better viewing.

This is one of the more affordable car battery testers on the list, and it's a favorite among its owners since it does its job with little fuss.

Many users praise this unit for its accuracy and the fact that it has a four-digit display, while other meters display up to three digits. There are however, a few users who have experienced failures with the device after a few months of use.

Look, this one is a bit old-school, but, well, there's nothing wrong with that. The 12-volt car battery isn't exactly cutting-edge technology, after all. The tester can handle 12V as well as 6V batteries, and is able to add up to a 100 amp load test to a 12-volt battery. That ability can show you hard to diagnose problems that more modern and more compact units can't. The battery tester can show you battery condition and let you know how many cranking amps are left. That lets you spot a weak battery long before it goes bad and leaves you stranded.

It has a rubber-insulated handle to make it easy to carry, while the large dial gauge on the front is easy to read. Especially in bright light, where LCD screens have trouble overcoming the sun. Hefty wiring and large alligator clamps make attaching this tester to your battery a snap. And if you find out your battery isn't the problem, this tester can show you if your alternator is running well without the need to re-connect or even flip a switch.

One of the more affordable options on this list comes from Cartman. The company's battery and alternator tester are compact and easy to read, with an LED display that indicates the condition of a 12-volt battery. When conducting a battery check using the Cartman Car Battery and Alternator Tester, you simply have to connect the red clamp to the positive terminal and the black clamp to the negative terminal of your battery - with your car turned off. The tester will then illuminate the OK light, followed by the battery state. If you want to check the state of your car's alternator, you simply have to turn the car on before connecting the two clamps.

Battery state is designated by Low, Medium, and High, and the charger will update the status as the battery charges. This device also lets you check the battery's condition before charging. If it's a steadily-lit LED, then your battery is in good condition and can be charged. But if the LED is off, then the battery voltage is out of range and could possibly be dead.

Clore Automotive offers a digital battery and system checker, although it is one of the more expensive products on the list. It's a 12-volt battery and system tester with 40-1200 CCA testing capacity. It has an operating range of 7 volts to 15 volts and is compatible with multiple battery types, including Conventional Flooded Acid, AGM Flate Plate, AGM Spiral Wound, and Gel Cell.

This device offers quick, easy battery and system analysis and can be used to test against a wide range of rating systems, including CCA, DIN, JIS, EN, and IEC. The front of the device features an LCD display for optimal viewing in all lighting conditions. It's also easy to use since the display walks the operator through the test sequence with instructions.

While most users do say this device is easy to use, some did say the instruction manual is a bit confusing and not very thorough. Some users also say they had trouble getting good contact with the clips.

Microprocessor-controlled, the Motopower Digital Battery Tester is designed to provide a quick reading to determine if a car's battery needs a jump or replacement. It's safe and simple to use, thanks to reverse hookup and over-voltage protection features. The front of the device has a four-character-lighted digital display, making this tester easy to read with accuracy.

Colored LEDs on the device indicate the status of your car's battery and alternator, while a black rubber, painted body makes it nice and durable. This tester uses 30-amp Alligator Clamps.

The testing range on the Motopower Digital Battery Tester is 4 volts to 20 volts for all types of 12-volt batteries.

Most owners praise this device for being easy to use with clear and concise readings. While it's a minor complaint, some users did say the cables are a bit short, so you may experience issues if your battery's terminals are far apart.

Another more expensive option comes from Ancel. This compact tester can be used on a wide range of 12-volt batteries and meets major battery standards, including JIS, SAE, EN, DIN, and IEC. It's designed to easily, quickly, and accurately measure the actual cold cranking amps capability of your car's battery, as well as the battery's health. Each reading will display the battery's CCA or AH value, charge percentage, voltage, internal resistance, and battery health percentage.

Conductance correlates directly to the battery capacity, and this device will never discharge or drain the battery. It can also be used to test the condition of a discharged battery and its passive testing method is safe to use. No internal batteries are required with this device, as it powers up once it's connected to posts on the battery you're testing.

This device can also be hooked up to a printer, so you can print out your test results.

Users who purchased this device praised the comprehensive data it provides while still being easy to use. However, the device is very compact with a small screen which some found difficult to read. There is also a small number of complaints that the screen easily gets scratched.

The Foxwell Battery Tester is one of the most expensive items on our list, but it's one of the most comprehensive testing devices you can buy. It will accurately test regular Flooded, AGM Flat Plate, AGM Spiral, and Gel batteries, allowing the user to analyze the battery health status to calculate the actual cold cranking capability of the battery and its aging status. Multiple rating systems are supported, including CCA, BCI, CA, MCA, JIS, DIN, IEC, EN, SAE, and GB.

This tester works on 12-volt and 24-volt charging systems and ensures the output voltage of the generator is normal, that the rectifier diode works correctly, and the charging current is normal. In addition, there's a comprehensive cranking test to check the starter system, cranking voltage, and cranking time in milliseconds so ensure the starting motor works correctly. Battery tests can be done in as little as 3 to 5 seconds.

The Foxwell Battery Tester features a premium-quality copper clip and wire, so it maintains a stable connection throughout the testing process. There's a 7.8-foot cable attached, so testing can be done from inside the vehicle. At the end of that cable are all-metal spray gold clamps, which are more solid and durable than normal clamps. A large backlight LCD displays all the information, while the device is fairly straightforward to use thanks to menu-driven operation. It also supports several different languages: English, French, German, Russian, Spanish, Dutch, and Italian.

Safety features on this device include short circuit protection and spark-proof protection.

What is a Car Battery Tester?

Why Do I Need a Car Battery Tester?

You want to purchase a car battery tester so that you can routinely check the state of your car's battery. This way, you know exactly when your car's battery is on its way out, allowing you to get it replaced before it completely dies and can't hold a charge. Most testers are affordable and they're a minor investment to save you from a potential headache of being stranded unexpectedly.

How to Check Your Car's Battery

Once you've purchased a car battery tester, it's time to see what condition your battery is in. Most testers will come with detailed instructions on how to operate the specific device, but here are some general steps and tips to follow.

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