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EV Won’t Start? Why You Should Check the 12v Battery

Owners of electric vehicles (EVs) might not think they have to pay attention to their 12-volt battery. After all, their EV also has a much larger battery that provides the electricity needed to move the vehicle and power the electric motor. Despite the presence of a high-voltage battery, EVs still use a 12v battery to power various electronic components, such as onboard computers, interior lighting, locks, and windows. 

Since the electricity from a 12v battery also helps start your vehicle, you should know why EVs need 12v batteries and how to check if your 12v battery is the reason why your EV won’t start.

Why Do EVs Have a 12v Battery?

While high-voltage batteries excel at powering your EV’s motor and handling propulsion for your vehicle, their high amount of voltage makes them unsafe for other functions. For example, high-voltage batteries in EVs tend to have 400 or 800 volts, and if they powered your vehicle’s smaller systems, hundreds of volts of electricity would be running through these systems all the time. This high voltage could create a significant safety issue, as a driver or passenger could come in contact with a great deal of electricity if a crash causes a short circuit.

Besides the safety concerns of high-voltage batteries, most of your EV’s electrical devices will only use 12 volts or fewer. As a result, your power door locks, HVAC fan, airbags, ADAS technology, power windows, and onboard computer run safely and effectively with a 12v battery. Even when your vehicle is off, your 12v battery will remain on, powering important systems like your vehicle’s alarm and other security features. If an EV used its high-voltage battery to continuously power these systems, it could strain the larger battery and shorten its lifespan.

Can a Dead 12v Battery Cause an EV Not to Start?

Though your EV needs its high-voltage battery for propulsion, the 12v battery plays a critical role in starting it. When you turn on your EV, the 12v battery will start the high-voltage battery pack. If the 12v battery is dead, your high-voltage battery won’t start (and neither will your EV!). 

What Causes a Dead 12v Battery?

Your EV’s 12v battery is almost always on, even when you’re not driving your vehicle. The electrical components in EVs also tend to consume more energy than those in gas-powered vehicles. Both of these factors cause your EV’s 12v battery to die faster, with EV batteries expected to last between three to six years. If your EV won’t start and your 12v battery is past the three-year mark, there’s a fairly good chance the battery is dead and needs to be replaced.

At times, however, dead 12v batteries can be due to mistakes from the manufacturer. In a Wall Street Journal article about 12v batteries in EVs, the writer discusses how software anomalies, sensor failures, and faulty parts have caused some EV 12v batteries to die prematurely and deplete faster than they should. Checking for news about recalls, needed software updates, or faulty parts concerning your EV can be helpful when diagnosing why your battery died. 

How Does an EV Charge the 12v Battery?

12v batteries in EVs will need to be charged regularly to perform at their best. If your EV’s 12v battery discharges too much and goes below its recommended voltage for too long, it can be damaged and need to be replaced. Without enough of a charge, your 12v battery also can’t properly provide enough power to your EV’s electrical components.

As a result, your EV’s high-voltage battery will trickle charge your 12v battery, delivering a small amount of electricity to it while your vehicle is on. Typically, your 12-volt battery will also be recharged when your EV is plugged into a charger. If your EV isn’t trickle charging the 12v battery properly, it could also be the reason for a dead EV battery. 

Turn to Chapel Hill Tire for EV Battery Repair and Replacement Services in the Triangle

If you’re EV won’t start and you’re looking for EV battery replacement services in Durham, Chapel Hill, Carrboro, Apex, Raleigh, or the surrounding Triangle area, Chapel Hill Tire has you covered. Our team can inspect your EV to find out if the 12v battery needs to be replaced. After our inspection, we can provide any repair or battery replacement services your EV needs to work at its best. We also offer a selection of coupons to ensure you can get a great deal on our services.

Learn more about our hybrid and EV services today. If you need to bring your car in for service, please make an appointment at one of our convenient locations in the Triangle Area.

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