BM2 is a Bluetooth-powered car battery monitor that delivers real-time voltage readings, historical voltage trends, and automated startup and charging tests, all synced to your phone. It also offers a Wear OS companion experience to view device and test data on your wrist. Recent updates include Android 15 compatibility, showcasing ongoing refinement of this mature tool.
Pros & Cons
Real-time voltage monitoring with historical trends.
Bluetooth-based data sync to the mobile app.
Wear OS companion for on-wrist access to data and tests.
Automatic startup voltage testing and charging tests.
Android 15 compatibility and ongoing updates.
Compared with some competitors, BM2 does not emphasize time-based or health-related metrics in its feature language (e.g., time, health, current, power).
Uses a broad set of permissions (location, Bluetooth, storage, camera) to function, which may raise privacy considerations.
User feedback
Ratings and reviews on Google Play
Comments on BM2 for Android
★★★★★4008 N Molter· Mar 17, 2026
Easy to install. Charging and battery information at my fingertips. Excellent price. Cant imagine needing anything else to monitor the health of my batteries and charging systems. Installed on my Ram 3500 diesel and my Kia EV6. Could not be more pleased.
★★★★☆Steve C· Oct 31, 2025
In this app, the battery currently shows 13.0 volts and 84% - what voltage do you expect a fully charged (100%) 12 volt battery to be?
★★★★★Paul Rodrigues· May 8, 2026
I love this app, and I love the device, I wish I would have an another level where it would tell you what is being drawn off your battery like a pair of draws in the value of amperage per hour, that would be a nice way to figure out if your vehicle has an issue. Otherwise agree app and a great product. Recommended for everyone who has an older vehicle.
★★★★★michael muchard· Apr 24, 2025
I've been using this device for several years on all of my auto, tractor, RV and RV toad batteries. It works great. Not only does it show the battery state-of-charge, it also shows the battery performance during starting which is a good indication the battery's remaining life. I found it so useful for monitoring my motor home's toad's battery while towing that I bought devices for my friends as a gift.
★☆☆☆☆bob haz· Apr 17, 2026
Why?\n Do you need access to all my phone data I don't want you monitoring where I'm at all times how fast I'm driving. Where all stops, I make Where I live when I'm home, when I'm not home. Somebody stares at me with binoculars. Reporting back to a third party is not acceptable. You peeping Tom, you. How is this acceptable? Peeping, Tom is against I just wanted to know what the level My battery was on my car. Now, your software has made the battery monitoring device undesirable
★☆☆☆☆M b· Sep 6, 2026
This app is absolute rubbish! Do not purchase this item or think that what you are seeing is correct. My battery went flat with this app showing the battery was in good health! Found out later that app wouldn't connect to Bluetooth, even after 3 reinstallations! Don't waste your time or money on this device!
★☆☆☆☆Ronald Erlston· Apr 23, 2025
Microsoft Defender has flagged this app on my Samsung phones as malware! Disappointing as the app was quite useful. Will only reinstall if cleared by Defender 😕
★☆☆☆☆AI AIN· Jul 31, 2025
App's voltage to percentage value is off by 30 percent. It shows my voltage as 12.23 volts as 38 percent. Look at any 12 volts car battery chart on the web, 12.2x volts is 60 percent.
★☆☆☆☆Andrew· Dec 1, 2024
App requires location access to function. There is no technical (functional) reason for this; it just exists to collect and send your data to China. Beware!
Google Play Rating history and histogram
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Store listing
By wanbaolu, from Google Play
Description by wanbaoluWritten by the developer, not by AppBrain. Click to read.
Battery Monitor BLE is an application for car battery monitoring, which can monitor the real-time voltage of the car battery; count the historical voltage of the battery; it can automatically test the battery startup voltage, and support idle and high-speed charging tests. All data is synced to the mobile app via Bluetooth.
And provides a Wear OS version, with functions including: displaying device data, battery test data, startup test data and charging test data on the Wear side through communication with the mobile phone BM2.
Recent changes: 1. Compatible with Android 16. 2. Optimized related details.
Safety and technology
Found in the app by AppBrain
Ads
No ads
Price
Free
Libraries
47
App size
14.3 MB
Needs Android
6.0+
Content rating
Everyone
Technologies used by BM2
23 permissions·47 libraries
Subscribe to see full permission and library details
Trust & Safety: BM2 requests a wide range of permissions including background location, location, network state, Bluetooth, storage, camera, and more to support Bluetooth data syncing and Wear OS features. Users should review the app’s privacy policy and ensure permissions are granted on least-privilege basis.
BM2 has been installed 180 thousand times.
Over the past 30 days, it averaged 41
installs per day.
Rankings
Google Play top charts
Google Play Rankings for BM2
This app is not ranked
About the app and developer
About BM2
BM2 is a tools app developed by wanbaolu.
Download Statistics
BM2 has been downloaded 180 thousand times. In the last 30 days, the app was downloaded 1.2 thousand times.
User Ratings
BM2 is rated 3.53 out of 5 stars. The rating is based on 1.9 thousand ratings.
App Information
BM2 is freely available from Google Play. The APK size is 14.31 MB. The latest APK version available is 3.8.1. The last update was on October 29, 2026.
Technical Requirements
BM2 requires Android 6.0+ or higher. The app has a content rating of Everyone. The APK has been available on Google Play since May 2016.
BM2 is made and published by
wanbaolu.
AppBrain is an independent app data site and isn't affiliated with wanbaolu.
The app name, icon, screenshots and description belong to wanbaolu and are shown as published on Google Play.
App Performance Report
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