Why Do Electric Cars Still Use The Humble 12V Battery
As the years go by, new EVs get smarter, more powerful, and can travel further than their predecessors. They are also becoming extremely reliable and offer you the flexibility of charging them at home, making them a Godsend to city dwellers.
Despite the relative complexity of their circuity, EVs are a lot simpler to operate compared to petrol powered cars. Instead of having hundreds or thousands of moving parts, hydraulics and fuel flowing through various tubes, they use an AC motor that receives a high amount of power from their sophisticated battery packs.
But did you know that despite their ability to deliver high flow of current in an instant, an EV still relies on a 12V lead acid battery for various tasks and functions? Though it may sound like an oxymoron, electric vehicles use two electrical systems to work effectively.
How Does It Work?
There’s the high voltage system, which relies on the actual battery pack, and it’s used to power the electric motor that makes the car move. The second one is the low voltage system, which is powered by a 12V battery. It’s used to power the car alarm, unlock doors, power the stereo, A/C, infotainment system and send power to the USB ports.
Why is this the case? Wouldn’t it be more prudent to consolidate both systems and have them run off the EV’s battery pack? The short answer to that question is safety. It’s safer to have a low voltage system to power things that you interact with, and which do not require much electricity to operate.
This includes operating the locking mechanism, door handles and interacting with the stereo system. Why would you need hundreds of volts for them? If there’s a malfunction, the chances of the 12V system hurting you in any way are extremely low.
It Also Functions Like A Safety Switch
Besides this the 12V battery works with the power relay to connect and disconnect the battery pack from the car’s electrical system. When you turn off an EV, the power relay cuts off the battery pack from supplying any power. Instead, all the auxiliary systems mentioned earlier, including the headlights, work off the 12V battery.
When you turn on an EV, the 12V battery supplies power to tell the power relay to reconnect the main battery pack to the EV’s system. That’s what gives the car the power it needs to move. The 12V battery then takes on the role as a buffer, helping to smoothen out the electricity delivery from the battery pack.
The “Cutoff” Systems Is A Safety Measure
Once the main battery pack becomes active, it begins recharging the 12V battery. This is like what happens in a petrol-powered car. The 12V battery is used to supply electricity to the fuel pump and starter motor to start the engine. Once that happens, the alternator, which runs off the engine, takes over and produces the electricity necessary to power everything and recharge the 12V battery.
This “cutoff” system in EVs also acts as a safety measure to protect emergency services personnel who respond to an EV crash or fire. Cutting off the electricity supply from the battery pack will reduce the chances of them getting shocked while attending to the vehicle’s occupants.
Manufacturers may eventually replace the humble 12V battery with a more sophisticated setup but that won’t happen soon. And if you plan to replace your EV’s 12V battery, check your owner’s manual or the nearest service centre for help. Odds are, it will be a deep-cycle one, which won’t be compatible with ones used with conventional petrol-powered cars.
