This small battery could be your EV’s worst nightmare!
Electric cars have often been criticized for their range and battery lifespan. But a new study reveals that the real issue isn’t the main battery pack. Instead, a much smaller component—borrowed from traditional gas-powered vehicles—is causing a surprising number of breakdowns. This overlooked detail could be responsible for repeated failures, even when the main battery is fully charged. Many drivers find themselves stranded, unable to start their car, without understanding why.
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A problem that’s often ignored
When people think about EV batteries, they immediately picture the large lithium-ion packs that power the motors. However, electric vehicles also have a 12-volt battery, just like traditional gas-powered cars. Its role? To handle essential vehicle functions like starting the system, infotainment, door locks, and more. The problem is that this small battery is more fragile than most think. Unlike a combustion engine car that recharges its battery using an alternator, EVs rely on a DC-DC converter that pulls energy from the main battery to keep the 12-volt system charged. But if this system malfunctions, the car simply won’t start—even if the main battery is at 100%!
Models most affected by this issue
Not all automakers face this problem equally. A study by Consumer Reports identified several models frequently affected by 12V battery failures. Among them are the Hyundai Ioniq 5, Kia EV6, Toyota bZ4X, as well as the American-built Rivian R1S and R1T. Online forums are filled with frustrated owners who have been caught off guard by their EV refusing to start, even when everything seemed fine. What’s worse? This issue isn’t exclusive to electric cars. J.D. Power, an automotive research firm, reports that starter batteries are becoming increasingly fragile across the industry, regardless of the type of powertrain.
Why charging is such a challenge
The issue isn’t just the quality of the batteries—it’s how they’re managed. Unlike gas-powered cars that recharge their battery while driving, EVs rely entirely on the DC-DC converter to keep the 12V battery topped up. Some EVs keep the converter running continuously, ensuring a steady charge for the 12V battery. Others, however, shut off the power once the car is turned off, leading to faster battery drain. This system still has room for improvement, and several manufacturers are already working on more efficient solutions. Another complicating factor? The increasing number of onboard electronics. Between connectivity systems, parking sensors, over-the-air updates, and digital screens, the 12V battery is constantly under strain. In some models, this can lead to excessive power consumption while the car is parked, causing rapid discharge.
Are solutions on the horizon?
Automakers are slowly recognizing the problem and looking for alternatives. Tesla, for instance, has started replacing traditional lead-acid batteries with longer-lasting lithium-ion 12V batteries. Some manufacturers are also developing smarter charging systems to extend the lifespan of the 12V battery. Additionally, emerging battery technologies, such as solid-state batteries and sulfur-based batteries, could eventually improve the reliability and range of electric cars. However, these innovations are still in development and won’t be available on the market for several years. For now, EV owners should pay close attention to their 12V battery—especially if their car has been parked for an extended period. Regularly testing the voltage can help prevent unexpected breakdowns.
This article explores why the small 12V battery is often responsible for EV failures, while the main battery is rarely the issue. It highlights the most affected models, explains the challenges of 12V battery charging, and presents potential solutions for the future. While the industry is evolving, EV owners should remain vigilant about this critical yet often overlooked component.
Image: © Hyundai
