MultiVolt speaks three protocols. While pairing, the app works out what is connected — in two stages: first listen passively for anything that announces itself, and only then start asking. That way not one byte is sent to a device whose language nobody knows yet.
Passive — the battery transmits by itself
The protocol of the LC-BT range. Once notifications are subscribed, the module transmits once per second on its own — nothing is ever requested. That is why Ective comes first in detection: the attempt sends not a single byte to the device and cannot break anything.
Active — the app polls it
The most common protocol in LiFePO4 house batteries with Bluetooth. Many brands sell the same electronics under their own name — to find out whether yours is one of them, look in the Bluetooth list for a name starting with "xiaoxiang".
Active — the app polls it
The D2 series and its relatives. Also an active protocol, with fixed thirteen-byte frames; depending on the radio module it runs over the vendor service or over a serial Bluetooth emulation.