It was at the Sun Trip 2019 and 2020 preparation weekend that I discovered this innovation. Thanks to Ralf!
So I decided to replace the BMS of my battery (battery management system) by a model with a bluetooth communication device. It cost me about thirty euros and a little more time than I imagined for the installation. Indeed, the connection pads of the BMS were different and I had to use the soldering iron.
No matter, I am satisfied with the result: now, I can know everything about the status of my battery, in real time, on the dedicated smartphone application. I still added a switch: it allows me to turn off the bluetooth module to avoid unnecessary discharge of the battery, for example during winter storage.