Is the definition of "BMS" consistent across industry and the marketplace? It seems that some products marketed as "BMS" include charging and balancing features, while others strictly refer to protections (such as thermal, overcurrent, under-voltage, etc). Are some retailers misusing the term?

examples
https://www.amazon.com/HiLetgo-Lithium-Integrated-Circuits-Protection/dp/B07X28845M/ref=sr_1_1_sspa
https://www.amazon.com/Weewooday-Charging-Battery-Protection-Lithium/dp/B08VDL8YFB/ref=sr_1_3

 

Are some retailers misusing the term?

I doubt it. It's a very general term -- Battery Management System

 

Strictly speaking, BMS is not a standard term. It covers a broad range of things related to protecting, charging, and maintaining batteries. That said, there is a general consensus (outside of ad copy) based on a threshold that a BMS is distinct from a protection board in that the former manages charging in detail (balance, &c) as well as enforcing limits such as charge rate and maximum voltage, discharge rate and minimum voltage, and providing instrumentation giving the battery state, while the latter has a very narrow function of protecting against over-charge (max voltage) and -discharge (min voltage), and maximum charge and discharge currents.

Calling the protection board a “BMS” is either a mistake or a lie—or, it is being done for a very specific and narrow reason. The expectation is that a BMS will include far more functionality than the simple protection board. That said, depending on the application, protected cells—that is a cell with its own protection board—as part of a battery can be a very good thing.