As electrification in the automotive industry progresses, high-voltage infrastructure is rapidly expanding. Charging networks are being developed by public and private organizations, and battery pack servicing, replacement, and recycling facilities are emerging. But an often forgotten part of an EV’s electrical system is its low-voltage SafetyPower ™.
Key Takeaways
- SafetyPower™ is a Midtronics technology. In an EV, it’s the 12V power that keeps critical safety systems running, including airbags, anti-lock brakes and ADAS features.
- An EV can lose those systems even when the high-voltage battery is fully charged, because they depend on the 12V battery.
- The 12V battery is recharged from the high-voltage pack through a DC-to-DC converter, so a weak battery or a weak converter can strand a car.
- Early warning signs include slow doors or windows, dash warnings at startup, a slow wake-up and unexplained infotainment glitches.
- SafetyPower Diagnostics™ is Midtronics’ 12V diagnostic technology for EVs, built to show whether the battery can support the vehicle’s critical loads.
In addition to the high-voltage traction battery, every electric vehicle on the road today has a low-voltage battery responsible for providing SafetyPower™ to critical vehicle loads, ensuring safe and reliable operation. Here’s a SafetyPower™ Primer – What you need to know about SafetyPower™, what it does, what occurs when it’s neglected, and how to maintain low-voltage batteries in EVs.
What SafetyPower™ Is
Alongside the high-voltage system is a 12-volt electrical system, similar to an ICE vehicle has. In many cases, it may even share some of the same parts as other models from the same manufacturer including power windows, power door locks, the infotainment system, and other interior accessories. However, the EV 12V battery’s most important function is providing SafetyPower™ to support critical vehicle safety functions.
In an EV, airbag systems continue to operate on a 12-volt system, as do the control modules that ensure essential functionality. Anti-lock brakes also rely on SafetyPower™ support as do the elements of the ADAS system, including:
- Lane Departure Warning
- Forward Collision Warning
- Collision Avoidance
- Emergency Braking
- Pedestrian Detection
- And more.
In general, critical safety systems rely on 12V SafetyPower™ for two primary reasons. First, the architecture of low-voltage systems mitigates the risk posed by potential faults within the vehicle infrastructure. For instance, a compromised wire could inadvertently expose drivers or technicians to potentially fatal high voltage. Second, in a collision or incident when the high-voltage battery is disconnected or fully discharged, the vehicle is intended to briefly function on 12V power to escape traffic come to a “stop” out of harm’s way.
What Can Happen If SafetyPower™ is Neglected
In an ICE vehicle, the 12V battery is recharged by converting mechanical energy from the engine to electrical energy by the alternator, which is then stored as chemical energy inside the battery. However, in an EV, the 12V battery is recharged with energy from the high-voltage battery pack via a device called a DC-to-DC converter.
However, failures are an inevitable reality as batteries possess a finite lifespan. Even AGM batteries, commonly employed in SafetyPower™ applications, typically last for approximately two to three times longer than standard flooded lead-acid batteries on average. Nonetheless, instances of premature failures have been observed to transpire more frequently than anticipated.
In fact, problems with the 12-volt battery are the primary reason for roadside events in all EVs. Drivers are often confused in such situations, as the high-voltage battery remains charged despite the car’s rapid loss of functionality, or even inability to move.
There’s no power to vital safety features or accessories. Basic vehicle access is prevented as doors and windows are left without 12V power.
While these symptoms may appear hypothetical, they are, in fact, grounded in reality. Numerous documented instances in the real world substantiate their occurrence.
- One driver’s car lost power while they were driving downhill. Their brake functions stopped working and they narrowly escaped an accident. The car only continued operating after boosting the 12-volt battery.
- Another driver lost acceleration in their car at highway speeds despite the HV battery showing 76% on the charge level. Everything else appeared normal except for their car would no longer drive.
- Another owner couldn’t get their power doors to unlock or open, it wouldn’t turn on, and the headlights would flash intermittently.
These concerns may instill a sense of skepticism towards electric vehicles, despite ample evidence that failures in EVs occur less frequently than internal combustion engine (ICE) vehicles. Given EV technology is still in its infancy, it is essential 12V batteries in EVs are diagnosed with appropriate technology to determine if sufficient SafetyPower™ Capacity is available to support critical vehicle systems.
SafetyPower Diagnostics™ – EV 12V diagnostic technology
No manufacturer or dealership wants their customers to be stranded on the side of the road put in harm’s way. EVs feature advanced automotive safety technologies, boast greater efficiency, and require lower maintenance compared to their ICE predecessors. Such incidents erode drivers’ trust and loyalty.
To pre-emptively address these concerns, it’s imperative to implement a 12V service strategy tailored to the EV application. Ensure that your operation is equipped SafetyPower Diagnostics™, Midtronics’ new 12V diagnostic technology, is the only available solution to accurately diagnose 12V batteries in EVs.
Service providers must be equipped with the appropriate diagnostic tool capable of precisely assessing the health of the 12-volt batteries in EVs to prevent the inconvenience of roadside service and ensure safe and proper function of the vehicle.
Signs an EV’s 12V Battery Needs Attention
Owners often assume that a car with a charged traction battery can’t have a power problem, so they miss the early signs. Watch for slow or intermittent door and window operation, dash warnings that appear at startup and then clear, a vehicle that takes longer than usual to wake up and infotainment glitches that don’t have an obvious cause. Any of these can mean the 12V battery isn’t delivering what the systems need.
Technicians should include the 12V battery in every EV inspection, along with the DC-to-DC converter output. A healthy battery with a weak converter will still run down, and a good converter can’t help a battery that has lost its capacity. Testing both gives you the full picture and saves the customer a second trip.
Frequently Asked Questions
What is SafetyPower™?
SafetyPower™ is a Midtronics technology. In an EV, it refers to the 12V power that supports critical safety functions such as airbags, anti-lock brakes and ADAS features like forward collision warning, collision avoidance and emergency braking.
Why does an EV still need a 12V battery?
The high-voltage pack runs the drive system, but airbags, control modules, brakes and driver-assist features run on the 12V system. The low-voltage design also limits the risk if a wire is compromised. If the high-voltage battery is disconnected or discharged in a collision, the vehicle is meant to run briefly on 12V power so it can move out of harm’s way.
What happens if an EV’s 12V battery is neglected?
The car can lose power to safety features and accessories even when the high-voltage battery still shows a charge. Drivers have reported brakes that stopped working, a sudden loss of acceleration at highway speed and doors that wouldn’t open. Problems with the 12V battery are the primary reason for roadside events in EVs.
How is the 12V battery recharged in an EV?
Through a DC-to-DC converter that sends energy from the high-voltage pack, not through an alternator. A weak converter can let a healthy battery run down, and a good converter can’t help a battery that has lost its capacity. Testing both gives the full picture.
What are the signs an EV’s 12V battery needs attention?
Watch for slow or intermittent door and window operation, dash warnings that appear at startup and then clear, a vehicle that takes longer than usual to wake up and infotainment glitches with no obvious cause.
What is SafetyPower Diagnostics™?
SafetyPower Diagnostics™ is Midtronics’ 12V diagnostic technology for EV applications. It’s designed to check whether an EV’s 12V battery can support the vehicle’s critical systems, so shops can catch a problem before the customer is stranded.