The end of 13.7 contains several notes. My understanding of notes is that they serve as recommendations but don’t carry the same requirements as items in the main body of the standard. Note 1 in the section recommends alternative power sources for critical systems. It’s worth noting, another lithium battery is acceptable as a redundant power source. The second note suggests that BMS should give an audible or visual signal when a disconnect condition is approaching.
I expected the standard would cover external communications in greater depth. An audible signal from a battery deep in a bilge is unlikely to be heard by an operator at the helm. Plus, in many cases, I think communication between the battery and charge sources could be more important than signaling the operator. Ultimately, batteries with external communications via CANBus or similar means can probably do both. I hope that over time the standard will be expanded to help ensure the safest possible operations.