Top 8 Best Car Battery Testers
By | Last updated: November 5, 2021
best automotive battery testers

Whether it’s a prized collector car or simply your daily beater, twisting the key (or pushing the button) only to come up with a fistful of no-go thanks to a dead battery is a deeply disappointing moment. Who left those devices plugged into the always-on 12V socket again?

There is a case for not simply ditching the old battery for a brand new one; whether that argument is environmental or financial is up to each particular gearhead. In some instances, it’s better to test the thing to see if it’s holding a charge before splashing out your hard-earned money on a new zappity lump. Also, not all electrical problems are caused by the battery, so a bit of diagnosis can help prevent wasting money on unneeded new parts.

It goes without saying we’ve looked at these battery testers through a standard 12V lens with the intent to identify problems with a traditional-style car battery. This post is not touching hybrids or pure EVs with a 10-foot (insulated) pole.

1. Editor's Choice: Topdon BT100 Car Battery Tester

Equipped with a large and easy-to-read TFT screen, this battery tester can directly detect the battery data and give suggestions on whether to replace the battery. It also has a cranking test and charging system tests that advise on repairing a circuit or buying a new battery.

According to the seller, it displays test results (actual cranking voltage & cranking time) of the starter system in milliseconds to indicate if the cranking system is working properly. Its load tester can check the 12V charging system, ensuring the output voltage is within spec and the charging current is with normal range.

Pros/Easy to use, handheld grips, you know I like the color
Cons/Monochrome display
Bottom Line/A solid all in one tester

2. Foxwell BT100 Pro Car Battery Tester

This is apparently FoxWELL, not FoxCONN, so any images of these things being assembled within proximity of an iPad should be put out of your mind. This 12V analyzer permits users to read details of a battery cell before blowing notes on a new one at Autozone.

A large backlit LCD display, combined with a clearly arranged keypad and menu-driven operation, make this tester much easier to operate. In fact, the ad says it is “especially born for beginners” which is an, erm, interesting way to phrase it. If you’re wondering it powers itself off the very battery it is testing.

Pros/Clear screen readout, “born for beginners”
Cons/Doesn’t test the starter
Bottom Line/Compact, simple operation

3. Ancel BA101 Professional Automotive Load Battery Tester

Baked into its small and compact design is an ability to read a much wider test range than some of the other testers in this post, with a spread of 100 – 2000 cold-cranking amps (CCA). If you’re wondering, anything over 1000 CCA is considered extremely robust by road car standards, so the lead-acid cube in your ’99 Cavalier will likely not exceed the tolerances of this tester/

It provides a check the alternator’s charging and starter’s cranking conditions, handy when diagnosing problems. A vehicle charging system test is also available, including load voltage, unloaded voltage, ripple status, and charging system status.

Pros/Detailed screen, lots of functions, ribbed for [redacted]
Cons/Cable isn’t terribly long
Bottom Line/A useful workshop tool

4. Schumacher BT-100 Battery Load Tester

Here’s an old school option that deploys a sweep needle to provide readouts, just like the band speedometer in your grandfather’s 1989 Chevrolet Celebrity. It tests 6V and 12V batteries up to 1,000 cold-cranking amps, making it suitable for most cars and light trucks.

Despite its decidedly vintage appearance, this tester is capable of testing load, battery condition, and starter motor draw. It features a top-mounted rocker switch for easier operation, worth noting in a world where some manufacturers decide to place power buttons right where one would normally rest their finger.

Pros/Great reviews from a large sample size, all the capability most will need
Cons/More difficult to read than a digital version
Bottom Line/Great for those with good eyesight

5. Autder Car Battery Tester

Remember LCD displays? If you’re of a certain age vintage, there stands an excellent chance those inch-high red numbers have been burned into your psyche thanks to a series of bedside alarm clocks. Whatever the case, that’s the type of readout deployed here.

At least it’s dead simple to read, with only four characters in its lighted display. Colored LEDs on the face of it indicate battery or alternator status with admittedly less precision than more detailed machines on this list. Picture a car with an idiot light for engine temperature instead of a gauge and you’ve got the right idea.

Pros/Dirt cheap, very simple
Cons/Fewer details than others
Bottom Line/Good for the basics

6. Suner Power Digital 12v Car Battery Tester

This tester has garnered a raft-load of good reviews thanks in large part to a pair of alligator clips more robust than most, contributing to its 4.5 out of 5-star rating. A good set of chunky rubber buttons doesn’t hurt either. This battery tester has a reverse polarity safety backup and is pocket-sized. Its CCA range is listed as up to 9555, a figure which your author triple-checked to ensure it wasn’t a typo.

Some customers complained the included instruction booklet was more difficult to follow than the current NASCAR points system, so be aware that there are a few resources online including some cheat sheets for common operations. Real-world recommendations abound.

Pros/Good clamping clips, beaucoup functions
Cons/Choose-your-own-adventure instructions
Bottom Line/Affordable and practical

7. OBDMONSTER 12V Car Battery Tester

Good for any 12V charging system, this cheap-as-chips (less than 7 dollars!) battery tester has an extremely basic display – but if all you need is a yes/no on the health of a car’s battery, it might just do the trick. It’ll apparently show if there’s an unnamed ‘fault’ along with state of charge.

Just don’t expect any fancy TFT screens or specific percentages. Customers describe it as “not a professional grade tool by any means” yet one that can “get the job done”. Hey, one doesn’t always need overkill in their toolbox. Manage your expectations about wiring quality in a unit costing less than a feed of McDonald’s, of course.

Pros/Beyond dirt cheap
Cons/Rudimentary display
Bottom Line/It might be all you need

8. Konnwei KW600 Car Battery Load Tester

We’ll round out this list with a battery tester is able to effectively analyze and read key car system data such as voltage, resistance, cold cranking amp and AH capacity, plus battery health and charge status. CCA reads up to 2000, by the way.

Displaying test results in text and graphing, this unit provides some of the most detailed information of anything on this list, making it great for the semi-serious mechanic or at least one who likes to give off the appearance they know what they’re doing. The LCD screen measures 2.4 inches, nearly as big as your author’s first TV and more vast than some OEMs first forays into digital infotainment systems.

Pros/Very detailed readouts
Cons/Getting spendy
Bottom Line/Impress yer friends

Best Automotive Battery Testers

How do you test a car battery to see if it is bad?

Honestly, it depends on the type of tester you are using. There are three types of automotive testers available in the market, namely:

  • Carbon Pile Tester

A Carbon Pile Tester is sometimes also referred to as a ‘Load Tester’. This tester type is the oldest among all, and comprises two analog meters to show D.C. Amperes and D.C. Volts, and a knob to put the cold cranking amps (CCA) load on the battery.

To test a car battery using a load tester:

  • Make sure that the needles for both volts are ampere meters are resting at 0
  • Connect the negative and positive cables of the tester to the corresponding points on the car battery
  • Notice if the needle for the D.C. Volts meter goes up to around 12. 6V and stays there
  • Rotate the knob to put half of the mentioned cold cranking amp load on the battery (E.g., If the battery says 800 cold cranking amps, use the knob to put 400 cold cranking amps of the load from the carbon pile tester)
  • Check if the needle on the D.C. Volts meter remains on 10V or above under normal temperature, i.e., around 21oC or 70oF (If it doesn’t, and the load tester starts making a beep sound, the battery needs to be recharged or replaced)
  • Volts Meter

This is a regular meter that checks the amount of voltage the battery holds.

To test a car battery using a voltmeter:

  • Switch the meter to D.C. Volts
  • Set the meter range anywhere above 15V
  • Touch the pins of the negative and positive cables to the corresponding points on the battery
  • Notice if the voltage remains around 12.6V or so under normal temperature
  • Next, start the car
  • Notice if the voltage remains above 10V (If the voltage drops below 10V, this means there’s some problem with the battery, and it needs to be recharged or replaced)
  • Conductance Tester

Sometimes also referred to as a Digital Battery Analyzer, these types of testers can check the voltage, cold cranking amps, resistance, and the condition of the battery. Such testers have a broad LCD screen to display the values.

To test a car battery with a conductance tester:

  • Connect the negative and positive cables of the tester to the corresponding points on the car battery
  • Turn on the tester
  • Optionally set the cold cranking amps
  • Check the values displayed on the LCD

Additional Info

If it’s a new battery, the resistance should not exceed 2mΩ to 3mΩ.

What should I look for in a car battery tester?

Nowadays, most people prefer Digital Battery Analyzer over the old-school Carbon Pile Load Tester. While the former gives an overall idea of the condition of the battery, the latter uses the real load to check if the battery is in a good state, and can be used. In any case, the voltmeter (multimeter) is a simple tester that only checks the amount of voltage the car battery holds.

Are car battery testers accurate?

Although it depends of the type of tester you are using, the quality of the tester matters as well. Assuming that you have a tester from a reputed brand, the factors that determine the accuracy level include:

  • How well the tester can check the cold cranking amps
  • How well the tester can check the battery voltage under normal temperature
  • How well the tester can assess the resistance in milliohms (mΩ)

Keeping all these points in mind, it would be a good idea to go for a carbon pile load tester so you can be sure of the values you get, and assess if the car battery needs to be recharged or replaced.

From time to time, TTAC will highlight automotive products we think may be of interest to our community. Plus, posts like this help to keep the lights on around here. Learn more about how this works.

(Editor’s note: This post is meant to both help you be an informed shopper for automotive products but also to pay for our ‘90s sedan shopping habits operating expenses. Some of you don’t find these posts fun, but they help pay for Junkyard Finds, Rare Rides, Piston Slaps, and whatever else. Thanks for reading.)

[Main photo credit: oatzpenz studio / Product images provided by the manufacturer.]

5 Comments on “Best Automotive Battery Testers: All Juiced Up...”

  • avatar

    Most people test their batteries with a turn of the ignition switch.

  • avatar

    Autozone, O’Reilly or any other auto parts store. They will test your battery for free.

  • avatar

    The testers like #4 (anything with this form factor, doesn’t have to be a Schumacher) hit the battery with a heavy load (large resistance heater coil) for 10 seconds [timed by your finger on the button] and show you the resulting voltage drop.

    The lightweight electronic testers like the others generally send an AC signal into the battery to estimate the internal ‘resistance’ (more technically impedance; I’m caveman-level here) of the battery. You enter the nominal CCA [cold cranking amps] rating of the battery (from the label) and the tester gives you a go/no-go based on its estimate of the actual CCA.

    More info:

    In my experience, it is helpful to have both kinds [load tester + impedance analyzer], because the electronic method will sometimes give you erroneous results.

    Now on the subject of battery testers, this little guy here is an *amazing* (the absolute best) tester to have around for good old AA and AAA [etc.] household batteries:
    • ZTS – Mini Multi-Battery Load Tester Mini-MBT

    It uses some Jedi-level algorithms to estimate the state of charge. Everyone I have given them to loves them (including sound technicians who *have* to know that all the wireless mics have fresh batteries).

    [They have a larger version which tests other battery types but the “Mini” is all you need.]

    • 0 avatar

      Some relatively affordable OBD-II scanners will walk you through a ‘battery test’ using the headlights and a starting cycle as the load.

      Earlier this week when the temperature dipped for the first time this Fall the ‘battery’ light came on in the Avalon (indicating a charging problem). Voltage while running was way too low at the battery, but the alternator was recently replaced with a brand-new (not rebuilt) unit (unusual for me). Restarted and everything was fine [charged the battery overnight after that]. Almost seemed like the car sensed low battery voltage (due to the cold weather) and didn’t even try to charge the battery. Don’t get too smart for your own good there, daily driver. :-)

      ANYWAY, I was reminded during that process that the vehicle computer knows the voltage it is seeing and can tell you that voltage via your trusty OBD-II scanner hooked up under the dash. Much easier (and warmer and potentially safer) than hopping out and using your voltmeter under the hood.

      Suggested life skill: Learn what your ‘normal’ battery voltage is when the vehicle is off, and what your ‘normal’ battery voltage is when the vehicle is running. Then when something gets weird you will know the difference. (I keep a little digital ‘cigarette lighter’ voltage gauge in my ancient truck for just this reason.)

  • avatar

    I prefer the old school load testers like the Schumacher – I’ve been wanting one for a long time.

    I thought about buying one of those battery monitors that plug into a power port (lighter socket), but Toyotas and Kias don’t have always-on power ports, and also turn them off during cranking, so the battery monitors won’t work.

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