Hi @johannv,
Our batteries do not have built in protection circuitry, if that is what you’re asking. The cells will not prevent themselves from being over-discharged, and there are not fuses built in that would prevent/reduce damage in the case of a short circuit. In effect they should be treated as a single large cell with a convenient connector.
Expected operation safety is reliant on monitoring the voltage (via telemetry and/or by setting up the battery failsafe in ArduSub). Additionally, our lithium-ion batteries (18/15.6 Ah) include a built in thermistor and connections to each group of parallel cells, that can optionally be monitored as an extra safety measure. Some people also choose to add fuses to various parts of their electronics.
It’s perhaps worth noting that having the power monitoring and safety features in the vehicle instead of in every battery means individual batteries are less protected when disconnected, but reduces the components required for protection when actually using batteries (since you can swap batteries without swapping fuses and management circuitry).