Battery Voltage Test,Cranking System Voltage Test,Charging System Voltage Test
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.
About BM2
BM2 is a tools app developed by wanbaolu.
How many times has BM2 been downloaded?
BM2 has been downloaded 170 thousand times. In the last 30 days, the app was downloaded 1.2 thousand times.
What is the rating of BM2?
BM2 is rated 3.54 out of 5 stars, based on 1.9 thousand ratings.
Is BM2 free?
BM2 is free to download. The APK download size is 22.05 MB. The latest version available is 3.8.0. The last update was on October 30, 2025.
What are the requirements for BM2?
BM2 requires Android 6.0+ or higher. The app has a content rating of Everyone. The app has been available on Google Play May 2016.
Description
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 15 2. Optimized related details
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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.
★★★★★kevin auman· Jun 22, 2024
I tell you what for $20 you sure get alot of very useful features/information about your batteries, I own 2 of these 1 for each vehicle & I know my voltage is a bit low to hit the remote start & let it charge up also I compete in car audio, so it helps to know the current voltage accurately & these are very close... Wish I was able to display both batts at once not have to go back & forth between them if I could suggest any additional features that'd be the only thing I'd improve... A+++
★★★★★David B Sears· Jun 4, 2025
I'm having a problem with battery charging on an MG5. Purchased a solar charger and installed, plus a battery monitor with a download of the BM2 app. When the ignition switched ON, showing 14.3v, switched OFF showing 12.6v, but solar charger is increasing this figure constantly, even when switched OFF. So it looks as though the items attached to cigarette lighter were drawing power off the battery while switched off?
★☆☆☆☆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
★☆☆☆☆Edison M· Oct 6, 2024
Location data is sent back to China. As proven in Hackaday. Runs on background invasively, drains battery. Beware!
★☆☆☆☆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.
★☆☆☆☆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 😕
Google Play Rankings for BM2
This app is not ranked
Technologies used by BM2
BM2 is requesting 28 permissions and is using 47 libraries.
Show 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.
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