The battery is at about 50% state of charge with2 purple bars showing. However running on the battery with no fuel will take the battery to a level where the engine will no longer start. This can also happen if the car is left in neutral with the AC left running as the engine cannot start in neutral to keep the HV battery charged. This has a knock on effect on the charge to the 12 volt battery as this receives it's charge via a dc to dc inverter from the HV battery The computer does not let the engine start when the HV battery is discharged to low to protect the battery from cell reversal, and this is well documented on the Prius forums. The Lexus CT200H uses all of the Prius drive system.
The battery self discharge rate is so slow that batteries that have been stood for 5 years have still maintained enough charge to register on the bar graph display, and start the car. Any bars showing on the display shows a charge level of above 40%, but not more than 80%. This is the range that the system is designed to work in to give long battery life.
John.
Thanks John for explaining this in detail. I'm still learning about this as I go along.
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