Having recently purchased a new battery, and wanting to do a deeper evaluation of its performance, lead to the consideration of a battery monitor gadget.
Such tools can store 30 days or more of data, as well as provide empirical evidence, rather than solely conjecture, about questions relating to the application, such as the suitability of AGM batteries in vehicles with charging systems not designed for them, or systems that don't fully charge batteries, by design.
A wireless data logger, combined with the pocket computer most people carry with them, would seem to be a simple and inexpensive solution, and does seem to be a popular option.
However, the extraneous functions, such as trip logging and location finding, also contained in the apps these tools connect to, didn't smell entirely right and promoted me to pause and do some further digging.
Which returned some interesting reading, in the form of a multi-part forensic deconstruction of the data these apps may collect, how it is collected, and where it is sent.
It is a long, and technical series, so one may wish to skip straight to the summarized piece last on the list, but the TLDR was that these apps logged more than the state of the battery, and that data was sent to other places for collection.
Also revealed is what is probably the original OEM for a popular battery tester, and a popular wireless monitor in question, both sold under various branding.
haxrob.net
haxrob.net
haxrob.net
haxrob.net
haxrob.net
It should be absolutely no surprise that this kind of thing occurs, in places far wider than a automotive tool, and by parties of every ilk. But it is interesting to see how it works, and what it does, exposed, in factual, objective terms.
Such is the modern connected world we live in, where a practical balance must be struck between utility, convenience, and sense of privacy.
Everyone has their own personal thresholds, and the intent here is to not tread into that territory, but simply to present the facts, so at least informed choices can be made.
Edit: cleaned up some typos.
Such tools can store 30 days or more of data, as well as provide empirical evidence, rather than solely conjecture, about questions relating to the application, such as the suitability of AGM batteries in vehicles with charging systems not designed for them, or systems that don't fully charge batteries, by design.
A wireless data logger, combined with the pocket computer most people carry with them, would seem to be a simple and inexpensive solution, and does seem to be a popular option.
However, the extraneous functions, such as trip logging and location finding, also contained in the apps these tools connect to, didn't smell entirely right and promoted me to pause and do some further digging.
Which returned some interesting reading, in the form of a multi-part forensic deconstruction of the data these apps may collect, how it is collected, and where it is sent.
It is a long, and technical series, so one may wish to skip straight to the summarized piece last on the list, but the TLDR was that these apps logged more than the state of the battery, and that data was sent to other places for collection.
Also revealed is what is probably the original OEM for a popular battery tester, and a popular wireless monitor in question, both sold under various branding.

Discovering that your car battery monitor is siphoning up your location data
Reverse engineering an Android app for a Bluetooth connected car battery monitor with some startling discoveries ...


BM2 - An analysis of location tracking in the AMap mobile SDK
Part 2 of the battery monitor series - A deep dive into the location tracking functionality of a popular location SDK package.


BM2 - Reversing the BLE protocol of the BM2 Battery Monitor
Part 3 of the battery monitor series -Analysing the BLE protocol in a car battery monitor to set the foundations to replace the application which tracks user’s location


BM2 - Dumping and modifying the battery monitor firmware
Part 4 of the battery monitor series - Two methods to obtain the firmware from the hardware for analysis and modification


That battery monitor that spied on it's users. What happened after it was exposed?
8th May 2024 - The following is an "archive" of the investigation done live over X / Twitter to find out what changes had been made after my expose on a popular car battery monitor which you can read here. At the time of the original postings, it had garnished over

It should be absolutely no surprise that this kind of thing occurs, in places far wider than a automotive tool, and by parties of every ilk. But it is interesting to see how it works, and what it does, exposed, in factual, objective terms.
Such is the modern connected world we live in, where a practical balance must be struck between utility, convenience, and sense of privacy.
Everyone has their own personal thresholds, and the intent here is to not tread into that territory, but simply to present the facts, so at least informed choices can be made.
Edit: cleaned up some typos.
Last edited: