TOPDON BT100 Battery Tester Review

Topdon BT100

In our continuous search for cool stuff that can be used for vehicle maintenance and diagnostics, we came across the BT100, one of the most affordable car battery testers from the popular TOPDON brand. It promises to do a full, reliable car battery test in a few minutes on a shoestring budget. 

Does it deliver? Let’s dig in and find out!

Tested by CCM

What We Like

  • Easy to use
  • Great value
  • Heavy-duty casing and battery clamps
  • Neat ergonomic design

What We Don’t Like

  • Rigid, short cables
  • No pouch or carrying case

Bottom Line

The TOPDON BT100 is a great battery tester, offering heavy duty quality for an affordable price. It’s easy to use and displays the results on a large screen with a clear conclusion so even the least technical DIY’er knows what condition the battery is in.

Tested by CCM

What We Like

  • Easy to use
  • Great value
  • Heavy-duty casing and battery clamps
  • Neat ergonomic design

What We Don’t Like

  • Rigid, short cables
  • No pouch or carrying case

Bottom Line

The TOPDON BT100 is a great battery tester, offering heavy duty quality for an affordable price. It’s easy to use and displays the results on a large screen with a clear conclusion so even the least technical DIY’er knows what condition the battery is in.


packaging of the topdon bt100

The first thing that stands out when you start to unwrap the BT100 is its simple presentation. It’s wrapped in a transparent, reclosable blister. Without opening the blister, you can already see its major components: a digital palm-size diagnostic tool with some large buttons and an LCD screen, and two sturdy-looking battery clamps. At the right-hand top corner of the blister, it clearly says it’s only intended for 12 volt battery testing.

backside topdon bt100 packaging

On the back of the blister, there’s a quick overview at what to expect from this tester: It claims to do a “Battery Test”, a “Charging Test”, a “Cranking Test” and that it also shows “Check Results” (GOOD/CHARGE/BAD) by displaying a green, orange or red light.

Finally, concealed on the inside of the blister, there’s an A5-size user manual in different languages. 

First Use and Settings

holding the topdon bt100

The BT100 sits nicely in your hand, and gives a good grip with 3 indents on each side for your fingers, which reduces the chance of accidentally dropping it when you have dirty or greasy hands from working on your car. It sure feels sturdy enough to handle daily workplace-related abuse.

close up of the topdon bt100

It’s got a nice big LCD display for easy reading, and you have 3 different lights that will light up depending on what result you have: “GOOD”, “CHARGE” or “BAD”. It’s got a little protector on the screen to prevent the screen from scratching during transport, but you can leave it on for extra protection if you want, of course.

The pushbuttons feel sturdy and give nice feedback with a clicky sound, which is nice. This gives a quality feel to it. There are 5 buttons: “Enter”, “M”, “Exit”, and an “Up” and “Down” button.

Battery clamps

The cable is not that long and feels kind of rigid, which is a pity because this means that you can’t take the battery tester with you inside the vehicle to perform the cranking and charging test and the stiff cable might prove a handful to work with, especially in cold temperatures.

The clamps on the other hand are really nice. They are well-designed, feel Heavy-Duty and inspire confidence. To further ensure a good connection they even have these nice copper teeth for extra grip.


the test setup used to test the battery tester

Before starting our test, we first fully charged our test batteries using our NOCO Genius 2×4.

the test setup used to test the topdon bt100 battery tester

Standalone Battery Testing 

To test the TOPDON BT100, we used 4 batteries in different stages of their life, ranging from almost perfect condition to dead: 

  1. Battery 1 is pretty new and works perfectly, and the continuous green light on our NOCO charging station indicates that it is fully charged. 
  2. Battery 2 is our backup battery, which is a few years old but still in good condition. It holds its voltage and has enough power to crank a car with ease. It is fully charged, also.
  3. Battery 3 is the most interesting test case out of the bunch, because it is old and bad but  holds its voltage and charges fully. While our charger says it’s fully charged, it does not have enough power to crank a car. 
  4. Battery 4 is 10+ years old and completely dead, it does not even charge fully anymore, and our NOCO charger doesn’t get beyond the first red charging stage, even if you charge it for days. Visually you can also see that it is bulging and when you touch the battery when it’s being charged, it feels a lot warmer compared to the other batteries. This is never a good sign and indicates very high internal resistance and/or dead cells.

First, we tested the batteries with a known, accurate voltmeter. This gave us a reference, a benchmark to start from and compare with. A voltage test is a quick test you normally would do to check if the battery is okay or not. 

Voltage meter test

Using a voltmeter only, these were the results: 

  1. Battery 1 measured 12.95V, a perfect reading for a nearly-new battery, as expected. 
  2. Battery 2 measured 13.02V, which is a great reading too for a battery that is a few years old.
  3. Battery 3 even measured 13.07V, which would make you think that this battery is perfectly healthy, but we know it isn’t.
  4. Battery 4 only measured 7.82V although it had been hooked up to our Noco charger for days. This was to be expected for a dead battery.

With the voltmeter measurements for comparison, we then tested the 4 batteries with the TOPDON BT100 battery tester:

attaching the battery tester

The TOPDON BT100 is very simple to use: You just have to hook up the clamps to the battery posts and the battery charger uses the battery’s power to function. It immediately turns on and even without having to do anything it gives the voltage that it detects. It’s very safe too: it’s reverse polarity and spark protected. 

voltmeter on the topdon bt100

The testing procedure is very simple: Press any of the 5 pushbuttons to go to the main menu. Then select “Battery Test”.

performing the battery test

Battery 1 is an AGM type battery so we scrolled through the menu and selected “AGM”. 

The next step was to select the standard in which our battery amps are rated:
All four test batteries are rated in “EN”, so we scrolled through the menu using the “Down” button until we found ”EN”, and then selected it by pressing “Enter”. 

The last step was to select the right amount of cranking amps: This can simply be found on the label of the battery. This battery is rated at 760A. After having selected the right amperage, we pressed “Enter” to begin testing.

battery test results

After the tester has processed for a bit, it will display all the measurements and tell you whether the battery is good or not. 

In our case, the tester said in huge letters on the display that this was a good battery, and also indicated this with a green light. Its state of health (SOH) was 82%, and the charge was rated 100%. It said the battery had a low internal resistance and when compared to the original 760A it still had 688A, according to the BT100.

Battery 2: At startup, the tester showed just above 13 volts just like the voltmeter did. Then we did a “Battery Test”. Once again, we selected “Battery Test”, and entered the correct parameters. 

After having processed the measurements, the tester concluded that this was a good battery, just like we already knew from experience.

battery test result second battery

Battery 3: This was the real test to see if the TOPDON BT100 could filter out a bad battery that manages to maintain its voltage. Once again, we selected the battery test, changed the parameters and let it perform its test.

result of the third battery test

And sure enough, this battery tester managed to detect that it’s a bad battery! Its state of health was only 24 percent and it only had 177 of the 360 cranking amps left, although the state of charge was 100 percent. It also had a really high internal resistance. So, also for this battery, the TOPDON BT100 did its job well! 

With a simple voltage test, there is no way to determine that this battery is bad, but the TOPDON tester immediately detected that this battery was bad and instructed to replace it. 

Battery 4: This last battery is bulging and gets hot when trying to charge it. After being hooked up to our NOCO charger for days, it still only read 7.6V. This clearly indicates high internal resistance and some dead cells.

power too low message

It was surprising that the battery tester even powered up with such a low voltage. However, when we pressed any button to go to the main menu, we immediately got a notification that the power was too low and we should retest after charging. Because this battery had already been charged for several days without showing improvement, this result meant it was clearly a bad battery. This confirmed  what we already knew.

reviewing the stored data

This tester has the ability, although limited,  to store test results. Or should we say test result (singular), because you can only review the last result, which is a bit of a pity. Regardless of the battery it is connected to, it will show the last test it has performed when “Review Data” is selected. It also lacks the ability to export any result to a printer or via email or text message.

load tester

As a third test, we triple-checked the measurements using an old-school load tester, and the results matched up perfectly with the results of the voltage meter and the BT100.

This confirms that the TOPDON BT100 performs battery tests reliably.

In-Car Battery Cranking and Charging Test

For the 4th and final test we tested the battery in our 98 jeep wrangler with our voltage meter, and then did a battery test, a cranking test and a charging test using the TOPDON BT100.

voltage test

A quick test with a voltmeter indicates that this is a healthy, fully charged battery. From experience we know that this battery has ample power to crank our car. 

Eager to test the TOPDON, we swiftly entered the parameters and started the test.

battery test

First impressions were good, the BT100 said it was a healthy battery.

cranking test

Then we did the cranking test. To do this, we went back to the main menu and selected the cranking test. After selecting this test, the BT100 instructed us to start the engine. TOPDON luckily designed these tests for single person use, so you don’t need a helping hand to start the engine. You do need to start it within 30 seconds of starting the test though. 

result of the cranking test

Once again, this battery performed well during the cranking test. The test showed a nice cranking time and voltage did not drop below 9 or 10 volts. This is important, because below these voltages, certain electronics can start to cause problems, and you don’t want that. 

increasing rpm to 2500 per minute

We also performed a charging test. For this test, you need to first start your engine. After confirming this in the menu of the TOPDON BT100, the device started performing a ripple test. This test was automatically followed by a load test. When this test had finished running, we received the instruction to increase the RPM to 2500 for 5 seconds.

result of the charing test

After pressing “Enter”, the tester started analyzing the data and after a short moment, displayed the results. The verdict was good: “Charging Normal”, our alternator appeared to work perfectly.

load test

Finally, we tested the battery again, but with the old school load tester this time. As expected, our battery had no problem withstanding this test. This confirmed that the TOPDON BT100 also performs an in-car battery cranking and charging test reliably.

The Verdict

If you’re in the market for an affordable car battery tester that is easy to use, you should definitely consider the TOPDON BT100. It’s easy to use with a nice big LED screen that is easy to read. It also has green, orange and red indicator lights to immediately see what shape your car battery is in. The BT100’s buttons feel sturdy and give a nice clicky feedback. Because of the grooves on either side of the casing, it allows for a firm grip without the risk of dropping it when you hold it with greasy hands. Because of its sturdy casing, it should be able to handle most workshop abuse though.

The battery clamps are Heavy Duty with strong springs and nice copper teeth. Somehow TOPDON even managed to make something as boring as battery clamps look cool. The short, stiff cables are the one thing that let it down though. It’s such a pity that they aren’t anywhere near long enough to reach into the cabin to perform cranking and charging tests like some other battery testers can. What’s also missing is a simple bag or carrying case, because now you have to dump it in a tool bag or try to cram it back in the plastic mold, and that’s not something you want to do on a regular basis.

But all in all, it’s a great device. So if you’re looking for a reliable battery tester that’s not too expensive and simple to use, then this one might be just for you. 


  • Great value
  • User friendly
  • Heavy Duty casing and battery clamps
  • Neat ergonomic design


  • Rigid, short cables 
  • No pouch or carrying case


Display 128x64 LCD display
Working Temperature -4°F~149°F (-20°C~65°C)
Storage Temperature -4°F~158°F (-20°C~70°C)
Dimensions 136.5mm*75.5mm*22.5mm
Weight 9.17oz (260g)

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