Why do even hybrid cars have 2 batteries?(12v + high-voltage)

Untraceable@lemmy.world to Cars - For Car Enthusiasts@lemmy.world – 14 points –

It feels kind if dumb to see such configuration and I have worries If I drain small 12v battery by using car with engine off It wouldn't start..

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https://greenbeanbattery.com/hybrid-vehicles-two-batteries/?gclid=EAIaIQobChMIkfjUrc2fgQMVYTbUAR1LIisoEAAYASAAEgJdk_D_BwE

Huh.

The 12v battery in a hybrid doesn’t start the car like you’d expect – it provides power to the computer, relays, ECU, etc. The heavy lifting of starting the engine is actually done by the hybrid battery.

I knew about the rest of the things it does because I can run my stereo and my headlights on my Prius without the battery indicator dropping. But I totally thought it also started the car.

Well in a technical sense you are also right, since the contactor for the main battery gets power from the 12v (albeit it's not a big load) Meaning if the 12v is completely dead the hv battery will not switch on and the motor will not start.