EV Battery Problems

Since the launch of pioneering EV brands, like Tesla, more than a decade ago, as a result of the active encouragement of governments throughout Europe, almost every vehicle manufacturer (VM) has added a multitude of hybrids and EVs to their product ranges. 

To achieve this they, and their supply partners, have invested hundreds of millions of euros into developing the electric motors, control systems and high voltage (HV) battery packs that they need to make these vehicles viable. 

However, despite the investment to develop these technologies, not everything in these vehicles is new, because 12-volt systems remain integral to EVs, just as much as they are in traditional cars, to enable them to perform vital functions. These include not only powering the lighting system, both internal and external, but the central locking, electric seats and windows, radio, alarm and other security features. It also powers the vehicle’s onboard computer and diagnostic systems and even plays a role in activating the main HV battery pack. All these systems put a significant strain on the 12-volt battery. 

This is because in contrast to a traditional car with an engine, which after providing a big burst of electrical energy to power the starter motor to start, the battery is recharged by an alternator, in a hybrid or EV, the 12-volt battery is charged by the HV battery and discharged by all the vehicle’s 12-volt systems, so it goes through lots of charging/discharging/charging ‘cycles’, something many batteries don’t cope well with. 

Irrespective of whether your car is a full EV, or incorporates an engine, the maintenance of its 12-volt battery is down to the vehicle’s battery management system, and this is where there is a potential conflict of interest.

As range anxiety has traditionally been one of the key barriers to EV uptake, VMs naturally want to maximise the range capability that they can offer owners. To do this, the battery management system will sometimes have to compromise between charging the 12-volt battery to keep it in top condition, and optimising the vehicle’s range. This is particularly likely when the HV battery reaches 20% state of charge or below, and can result in the 12- volt battery being undercharged, subsequently affecting its ability to power the systems that rely on it, as well as its useable life. 

A further impact on the life of the 12-volt battery comes with the advanced technology inbuilt into modern vehicles. Their inherent connectivity and the multitude of apps they can run, such as to remotely ’wake it up’ and activate the 12-volt system, for example, can require thousands of activations per day, which can seriously discharge the 12-volt battery and leave the driver with a lifeless car. 

Spending a couple of weeks in an airport car park, for example, can be an especially testing time, as the HV battery can be often significantly discharged, which can have a knock on effect on the health of the 12-volt battery, and means it may not get you home without a recharge.

Although the VMs work hard to update their systems when they find these problems, you might well have experienced some of the issues that have been highlighted, but it’s possible to minimise the potential risk by being proactive. 

The first thing to do is to ensure your EV is properly charged by following the VMs recommendations. Another wise precaution is to visit your local independent workshop and ask them to check the condition of the 12-volt battery, and to find out whether it can be upgraded with a version such as an AGM battery, which is better suited to the repeated nature of those charging cycles mentioned earlier. 

Applying these two simple principles will significantly reduce the risk of you becoming one of these aforementioned European breakdown statistics.