GregsterEV
Well-known member
There is a reserve buffer . The State of Charge displayed is often 4-6% off vs whats SOC BMS on the top end and low end.I m surprised ev car don’t have a reserve as in even if you reach 0% you should still be able to drive 20-30km to reach a recharge station
Many ICE cars, especially toyota/lexus you can drive down to 0 km range and still have 3-5 liters in the tank, it s a protection to ensure ppl dontget atranded on aaide of road
Idiotproof kinda thing
To manage the reserve, the system will start limiting power output and electrical consumers (hvac for example) Engagement of “Turtle Mode” depends on manufacture fail safes with low pack voltage Example Tesla at 0% isn’t nearly as bad as Vinfast was. Even Ford in my experience isn’t that bad or Hyundai at low pack voltage.
Some EVs don’t like to be charged from 0% SOC BMS. You need to disconnect the 12v plug in, reconnect 12v and initiate the charge. GM for example. Ford will have a very long handshake time at low pack voltages. All EVs on cold, low voltage low SOC packs could encounter charging issues. This is what happened in Chicago last year, ride share drivers were showing up very low SOC, cold packs and failing to charge or unable to charge
I have software that can measure all this. Pack voltage, SOC BMS, cell temp, pack temp, charging etc

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