Battery Capacity Down to 86.8% After 18,000 Miles

[gnuarm]

The buffer at the bottom of the battery isn't for the driver, it's for the car. At a certain point, the battery is isolated and stops providing power for any vehicle functions, including recharging the 12V battery. That buffer is well above the point where permanent damage is done to the battery and it's the reason that the car can sit for months, dead at 0% charge without being permanently bricked. It just needs to have the 12V jumped and be plugged in to charge to be brought back to life.

Driving past 0% or 0 miles is just luck that the BMS calibration is off in your favor, stopping at some low miles/km range is off to your detriment. The buffer isn't a reserve tank.

Ok, so the "buffer" has nothing to do with range. That's what I thought and only makes sense if the goal is to protect the battery.

But wk057 is being quoted, "4 kWh unusable bottom charge". That says the 4 kWh at the bottom can be used to drive the car although likely at a reduced output. I seem to recall crazy Tesla Bjorn driving at 2.5 kph to reach the charger. I haven't seen that video in a long time.

 

[Krazaak]

But wk057 is being quoted, "4 kWh unusable bottom charge". That says the 4 kWh at the bottom can be used to drive the car although likely at a reduced output. I seem to recall crazy Tesla Bjorn driving at 2.5 kph to reach the charger. I haven't seen that video in a long time.

To me, unusable says unusable. Reducing power output by driving slow might let the BMS drain power from cell groups that aren't at the critical voltage yet, due to battery balance issues, but once you try to draw power that drops voltage beyond a certain point, you're cut off.

The only reason the 4kWh buffer matters, is because it means that the ~102.5kWh pack only has ~98.5kWh of energy capacity you can actually use.