The BMS monitors the throughput of current to and from the battery, by connecting directly onto the battery negative terminal you would bypass the monitoring device and screw up the charging algorithms. By connecting directly to any other ground stud on the vehicle, you're ensuring that the charge and discharge current is seen by the BMS, that's all. Nothing bad will happen, just the vehicle systems won't operate necessarily as intended. Carrying out a battery discharge test through the BMS isn't a good idea though.
 
Electrically no, most use some sort of shunt to measure the current and are generally very accurate - accurate enough to measure quiescent current down to single mA and high enough to measure starter current in the 100's of Amps. Some of the early ones were true 'series' devices and were often damaged if the vehicle was incorrectly jump-started. The BMS usually communicates on a LIN to whichever module has the supervisor function for charging, autostop, etc.

If anyone is interested / suffering from insomnia, attached is the Description & Operation document for L405 battery management
 

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Electrically no, most use some sort of shunt to measure the current and are generally very accurate - accurate enough to measure quiescent current down to single mA and high enough to measure starter current in the 100's of Amps. Some of the early ones were true 'series' devices and were often damaged if the vehicle was incorrectly jump-started. The BMS usually communicates on a LIN to whichever module has the supervisor function for charging, autostop, etc.

If anyone is interested / suffering from insomnia, attached is the Description & Operation document for L405 battery management
It probably uses a Hall effect device rather than a shunt.
 
They do, I was just trying to keep things simple without opening another rabbit-hole... The early ford ones were a simple induction coil but suffered from drift if driven / parked for too long.
 
Well back too using the RR, got the father in laws mini to sort so iv left mine at his,
Facebook memories came up thought id share,
Screenshot_20240125_101412_Facebook.jpg
 
Replaced the desiccant in the air suspension drier - wasted time and money on that then, still have the same fault. Grr!
  • C1A13-64 (AF) Pressure does not decrease when venting gallery - Algorithm based failure - signal plausibility failure

The strange thing is that it always lowers when using GapIID but almost never lowers the front of the car when selecting access mode (or when it needs to do it itself)
 

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