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Electric vehicles (EVs) run on powerful high-voltage battery packs, usually ranging from 400 to 900 volts, that drive the electric motor.
But many drivers are surprised to learn that EVs also include a standard 12-volt battery. So, what exactly does this small battery do in a modern electric car?
Why Do EVs Still Have a 12-Volt Battery?
Despite the advanced technology behind EVs, they still rely on a traditional 12-volt battery, just like gas-powered cars.
This smaller battery powers essential low-voltage systems such as:
- Central locking and alarm systems
- Power windows and mirrors
- Headlights, wipers, and interior lighting
- Infotainment systems and dashboard displays
- Onboard computers and sensors
- Electric seat adjustments and steering columns
Most importantly, the 12V battery controls the relays that allow the high-voltage system to activate safely. Without it, your EV wouldn’t even be able to “turn on.”
How Does the 12V Battery Get Charged?
EVs don’t have alternators like gas-powered cars. Instead, they use a DC-DC converter to draw power from the main high-voltage battery and step it down to charge the 12-volt system. When the vehicle is plugged into a charger, the 12V battery is usually topped up as well.
Some plug-in hybrids may use regenerative braking or an onboard generator to keep both battery systems charged, depending on driving conditions.
What Happens if the 12V Battery Dies?
If the 12-volt battery dies, your EV may not start, even if the main battery is fully charged. That’s because critical systems rely on the 12V battery to power up the car’s computers and unlock the high-voltage system.
In most cases, you can jump-start the 12V battery using a portable jump starter or another vehicle, similar to traditional cars. Some EVs even allow the main battery to recharge the 12V battery with a push of a button, but this depends on the model.
If the battery can’t be revived, it will need to be replaced, ideally by a certified technician due to the presence of high-voltage components nearby.
Are 12V Batteries Important?
The 12-volt battery may seem simple, but it plays a critical role in every EV on the road. Keeping it healthy ensures smooth operation and avoids frustrating breakdowns. Always check your owner’s manual for exact instructions, and if in doubt, consult a professional for support.