A Review of the TOPDON BT100 Battery and Alternator Tester

Updated on June 14, 2020
eddiecarrara profile image

I'm a tool guy and love to put tools through the test. When I find a tool that can make life's every day projects easier, I like to share.

TOPDON BT100 battery and alternator tester
TOPDON BT100 battery and alternator tester | Source

I Upgraded to a TOPDON Battery Tester

I have several machines that use 12-volt batteries and they sit around during our cold winters. At the end of every winter, you never know what condition the batteries will be in.

I have an old analog battery tester, but I thought it was time to update it to something that actually gave me a digital reading, instead of showing me a needle on a graph where I would guess what numbers the arrow is pointing at. I didn't want anything too complicated, and I didn't need to spend the money on a tester with a printer. Since I already owned the TOPDON battery jump pack and I know their customer service is beneficial, I thought I would give the BT100 a shot.

I like to have a unique tool like this TOPDON BT100 in my toolbox because I have three kids who own cars, and I have a wife, so I'm the guy everyone calls when they have a problem with their vehicle. Whether it's just a question or they need me to test something, this little battery tester fits the bill.

The BT100 uses the vehicle battery for power, which at first I thought was a bad idea. Still, after thinking about it, you'll never have a low battery, and you won't have to deal with batteries deteriorating, leaking acid, or damaging the tester.

BT100 Test Results

I used the BT100 to test several batteries. I found that the test results are consistent and accurate to the best of my knowledge, I've gone as far as trying the same battery three times in a row and the test results were very close to exactly the same.

I found when using some of the more expensive battery testers that their test results are not as consistent as the BT100. When using a more expensive battery tester, running the same test on the same battery three times in a row, I would get three totally different test results. These testers cost close to a thousand dollars, and with inconsistent test results, how could I rely on the test results being accurate?

The BT100 Can Test Several Different Types of Batteries

  • Regular flooded (liquid sulfuric-acid-filled, the most common car battery)
  • AGM flat plate (absorbent glass mat)
  • AGM spiral (spiral plates)
  • Gel (electrolyte mixed with fumed silica)
  • EFB (enhanced flooded battery)

My Test Results With the TOPDON BT100

Charging System Test With the BT100

Testing the charging system was easy. I connected the clamps, ran the engine with no load, and used the tester to run a ripple test on the diode and windings. Unfortunately, I didn't have a chance to use the BT100 on a damaged or worn alternator, only on a good performing alternator.

When running the ripple test, the ideal pattern should be consistent with small ups and downs. High or low spikes indicate there is a problem with the system. Downward spikes suggest a problem with the diode, and upward spikes suggest a problem with the windings. The BT100 should detect either problem during the test.

BT100 Cranking Test

The cranking test measures the time it takes for the engine to start in milliseconds and how low the battery voltage drops during engine cranking. The manual does have a reference table to indicate what voltage is acceptable and at what voltage the battery will need to be replaced.

It would be nice if the BT100 cable was longer so you could hold it during the cranking test, but it's not necessary. When you do the cranking test, it's best to place the BT100 on a secure surface like the hood cowl or shock tower, not on the engine; when the engine starts it creates a lot of vibration, and the tester could drop and become damaged.

A thin rubber or silicone cover would have been a nice upgrade to this tester for better handling and comfort, but at this price, you can't complain.

TOPDON BT100 Pros and Cons


  • Lightweight and compact
  • Easy to use and understand
  • Consistent battery test results
  • Quality battery clamps, good spring tension
  • Backlit display
  • Uses vehicle battery for power (never needs batteries)
  • Alternator test
  • Stores last test result after disconnecting
  • Low price point
  • Language options
  • 2-year warranty
  • Excellent customer service


  • Short cable (personal preference)
  • No printer (typical at this price point)

Common Mistakes When Testing Batteries

I find the most common mistake people make when using a battery tester is to input the wrong battery information like the type of battery and the cold cranking amps (CCA), which skews test results. Battery information like cold-cranking amps and battery type can usually be found on the battery label. If you can't find it on the label, a simple Internet search using the battery group number and brand can verify the information.

This BT100 is a DIY must-have battery tester, it's compact enough to keep in the car glovebox or in one of your smallest toolbox drawers. I have used both expensive and inexpensive battery testers during my busting knuckles years, and this is one of the easiest battery testers to use with the most consistent test results.

If you have any questions that I didn't cover in this article, leave them in the comment box, and I'll do my best to answer them.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Eddie Carrara


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, axleaddict.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://maven.io/company/pages/privacy

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
    ClickscoThis is a data management platform studying reader behavior (Privacy Policy)