Why does…? #22 — why an electric car still has a small 12 V battery
The big battery is switched off when the car sleeps; a small 12 V battery runs the computers, locks and lights and wakes the big pack's contactors.
A giant battery… and a tiny one too? Why does an electric car still have a 12 V battery? 🚗🔋
⚡ The big pack holds about 400 volts (some cars 800 V).
🔒 When the car sleeps, big switches cut it off — safe for crashes and repairs.
💡 Locks, lights, the screen and the car's computers all run on 12 volts.
🤔 So who wakes the big battery up?
✅ The small one! It powers the computers that close the big switches.
🔁 Then the big pack recharges it while you drive (a DC-DC converter turns ≈ 400 V into ≈ 14 V).
(A few new cars use a 16 V lithium one — same job.)
Read the voiceover (transcript)
- A giant battery, and a tiny one? Why?
- The big pack holds about four hundred volts.
- When the car sleeps, big switches lock it away.
- Locks, lights, screen and computers run on twelve volts.
- So who wakes the big one up?
- The small one! It closes the switches.
- Then the big pack recharges it.
- Next: why USB-C fits both ways. Follow for more!
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