Miscellaneous Electronics Will Drain The 12V Battery Of Your Chevy Volt, And Dealers Know About This Well-Known Issue, But May Charge You To "Diagnose" It

In response to our recent article detailing a Hyundai Ioniq 5 owner's experience with a dead 12V battery after a 10-day parking period, Dave Turvene shared his insights from owning a 2012 Chevy Volt until February 2025. He highlighted a persistent issue: the 12V battery drain caused by miscellaneous electronics, which is well-known among Volt owners.

"I had a Chevy volt 2012 until February of 2025. The 12V battery drain was a well-known issue. You either drive it to recharge the battery or keep it plugged in. Otherwise the miscellaneous electronics will drain the 12V battery. When this happens the best solution is a portable jump charger, but after a couple jumps the 12V battery will fade and need to be replaced. The dealer service shops ALL know about the this issue, but may charge you to "diagnose" the issue. If so, it's like a scam! Just be aware that it's a problem and prepare for it."

This type of battery drain isn’t exclusive to the Hyundai Ioniq 5 or the Chevy Volt. In fact, even Tesla owners face unexpected battery loss when leaving their vehicles unplugged for extended periods. One Tesla Model 3 owner ran a revealing test by leaving the vehicle idle for 12 days—and the results might surprise anyone who assumes EVs sleep soundly in the garage. Here’s exactly how much battery a Tesla lost over 12 days without charging—and what that could mean for your own EV.

Turvene noted that unless the vehicle is driven regularly or kept plugged in, these electronics can deplete the 12V battery. He recommended using a portable jump charger as a temporary solution but cautioned that repeated jumps would eventually necessitate battery replacement. Turvene also expressed concern that dealers, despite being aware of this common issue, might still charge owners for a "diagnosis," likening it to a scam.​

Turvene's experience underscores a broader concern in the EV community: the vulnerability of the 12V battery system. While EVs are lauded for their advanced technology and efficiency, the traditional 12V battery remains a weak link. This battery powers essential systems like electronics, lights, and safety features. When the vehicle is idle, these systems can continue to draw power, leading to unexpected battery depletion. This issue isn't isolated to the Chevy Volt; other EVs, including the Hyundai Ioniq 5, have reported similar problems.​

Using a portable jump charger can provide a quick fix, but it's not a long-term solution. Repeatedly jump-starting the 12V battery can reduce its lifespan, eventually requiring replacement. To mitigate this, some EV owners use battery maintainers or trickle chargers when their vehicles are parked for extended periods. These devices help keep the 12V battery charged without the need for frequent driving or plugging in. (Ref. CTEK).

While a portable jump charger can be a lifesaver in a pinch, there’s an unexpected alternative that many EV and hybrid owners overlook—one that might actually be safer and more effective long-term. In fact, there's a growing case for why we should stop jump-starting cars altogether and consider using a different tool that’s smarter, more protective of the vehicle’s sensitive electronics, and less likely to cause further battery degradation. Here’s a look at what you should be using instead—and why it could save your battery and your sanity.

Modern EVs are beginning to address this issue with improved battery management systems. For instance, some newer models monitor the 12V battery's charge and automatically recharge it from the main battery pack when necessary. However, not all EVs have this feature, and owners should consult their vehicle's manual or manufacturer to understand their specific system.​

The 12V battery drain issue highlights the importance of understanding all aspects of EV ownership. While the main battery pack often receives the most attention, the auxiliary 12V battery plays a crucial role in vehicle functionality. Being aware of potential issues and proactive in maintenance can prevent inconvenient breakdowns and unexpected expenses.​

What’s often overlooked - yet critically important - is knowing exactly when and how to test your 12V battery before it catches you off guard with an unexpected failure. Preventive maintenance can go a long way in avoiding the kind of situation Dave Turvene described, and there are specific steps every car owner can take to catch a weak battery early. This ultimate guide on battery maintenance, testing, and replacement breaks it all down in simple terms—even covering tips that many dealership service advisors won’t tell you unless asked.

We'd like to hear from you:

1. Have you experienced 12V battery drain issues with your EV?​
2. What solutions or preventive measures have you found effective?​

Share your experiences and insights in the comments below to help fellow EV owners navigate this common challenge.

Armen Hareyan is the founder and Editor-in-Chief of Torque News. He founded TorqueNews.com in 2010, which since then has been publishing expert news and analysis about the automotive industry. He can be reached at Torque News Twitter, Facebook, Linkedin, and Youtube. He has more than a decade of expertise in the automotive industry with a special interest in Tesla and electric vehicles.