BMS instead of Fuse/Breaker

[Short_Shot]

Please describe the scenario when the fuse would do something better then a BMS would do.

That's not really in context here tbh.

The appropriate issue to address is whether the bms can do something a quality fuse cannot.

Until a BMS provides ground fault interruption I'm not going to consider it a safety device. Overcurrent is a nice bonus but fuses have the proven history.

 

[John Frum]

Counter question - Is a fuse needed with a proper wire layout? Or is the BMS as overcurrent device sufficient?

I think I already mentioned in this thread that the BMS's fets can weld closed.

 

[FilterGuy]

Counter question - Is a fuse needed with a proper wire layout? Or is the BMS as over-current device sufficient?

If the BMS works correctly, then it is sufficient. However:

• The BMS requires a complex set of hardware and software to all function properly to quickly shut off the current. There are a lot of possible failure modes.
• The fuse requires one resistive element to heat up and burn out. There are not very many failure modes for a fuse. In fact, I would say the most likely failure mode with a fuse is if you buy it from a cheapo manufacturer and it is not what it is advertised to be.

The fuse will always be more reliable so the question comes down to weather the BMS can be reliable enough. To be honest, I can't prove the BMS's over current function is reliable or unreliable. However, like many others I am not ready to trust the BMS when a fuse is so easy to add.

 

[Shunt Czar]

You may want to read the following. I have also secured a report on the actual circuitry and implementation in the Tesla Model Y and intend to write on, especially if I find issues. There are good references in here why the aircraft industry does not do this. There is a path forward for automotive but the devices do not exist yet.

http://www.how2power.com/newsletters/2011/articles/H2PToday2011_design_RedHillLabs.pdf?NOREDIR=1