Why Do Electric Cars Still Use Lead-Acid Starting Batteries?
- by Joe Weber - updated on 12/21/2023
Electric cars are propelled with a very sophisticated and high-tech lithium battery system. But did you know that even with this new technology, electric cars still use a 12-volt lead-acid battery to power key equipment and features when you enter the car?
What Does a 12-volt Battery Do in an EV?
The motors that propel the vehicle forward are powered by the lithium battery system that produces anywhere from 375-450 volts. Some models are even using 800-volt systems. So, what the heck is a small 12-volt lead battery doing in there?
It's a pretty simple answer, really. All vehicles on the road today have convenience features like climate control, heated seats, infotainment systems and the list goes on. This isn't different for EVs, if anything they have more electronic accessories. All of those accessories, in every car, are powered by a 12-volt system. That's the way it has always been and it doesn't seem like a change is coming anytime soon.
So, no, the 12-volt battery doesn't propel the car but it does power everything else that you are accustomed to using while driving.
Why Can't the High-Voltage Lithium Batteries Power Everything?
Electric vehicles are still very new and therefore haven't been able to really drop in price for the masses to start buying them. Designing and developing a new high-voltage system, or converting 12-volt systems to safely use the high-voltage lithium batteries to power all of the current accessories in the vehicle would add even more cost to an already costly venture.
How is a 12-volt Battery Charged in an EV?
Fully electric vehicles don't have engines, therefore they don't have alternators like you see in vehicles with internal combustion engines, so how are the lead batteries kept charged while driving?
The answer to this question is not as simple. The high-power voltage from the main battery system can't just be sent to the 12-volt battery to charge it, that would have disastrous repercussions. Instead, the voltage is run through a converter to convert the 375 volts, or higher, to 12 volts so it can be safely used to charge the lead-acid battery.
Some electric vehicles even come equipped with a small solar panel that captures the sun's rays to trickle charge the battery.
What Happens When the 12-volt Battery Dies?
The entire car runs on large, high-powered lithium batteries, so what happens when this one, tiny 12-volt lead-acid battery dies? The answer might surprise you. If your small lead-acid battery dies, your EV will act just like an internal combustion vehicle and be dead in the water.
The massive lithium battery system may propel the car but most of the important electronics in the car are powered by the 12-volt lead-acid battery system. If that battery dies, you will be unable to unlock the doors, turn on the lithium system or even charge the lithium batteries. The entire system is reliant on the lead-acid battery.
Can You Jump the 12-volt Battery?
Yes. You absolutely can, although you are not trying to crank an engine that requires massive amounts of energy. The goal is to get the battery back to a stable state of charge so the electronics in the vehicle work. You can use a quality jump pack as an immediate solution but a battery charger/maintainer would be ideal.
Note
These batteries are usually in hard-to-reach places, like behind the glovebox or behind a panel in the trunk. Not like the starting batteries on gas or diesel engines. Because of their location, they can be hard to reach to test or replace. If you need help or don't feel confident about doing either of those things yourself. Drive on over to Batteries Plus and we'd be happy to help.
What Type of Lead-Acid Battery is Used in an EV?
The lead-acid batteries commonly seen in electric vehicles are similar to those seen in normal gas or diesel engines, with a couple of exceptions.
Absorbed Glass Mat (AGM)
AGM batteries, short for absorbed glass mat batteries, stand out as a preferred option for many car manufacturers and battery producers crafting cells for electric vehicles. These batteries require minimal maintenance and prove especially suitable for vehicles equipped with advanced electronic systems, a characteristic common in electric cars.
Notably, AGM batteries boast quick recharge times and a lifespan approximately double that of standard flooded lead-acid batteries.
Enhanced Flooded (EFB)
EFB, which stands for enhanced flooded batteries, is another choice gaining popularity among car manufacturers. These batteries come with internal enhancements, such as the inclusion of carbon in the plate manufacturing process. This addition improves cyclic stability and charge acceptance, especially when the battery is running low.
EFB batteries are the middle ground between conventional flooded batteries and AGM batteries.
Deep Cycle
Some, not many, electric vehicle manufacturers opt for deep-cycle batteries. These batteries are specifically built with thicker internal plates to enhance their ability to absorb energy. They stand out for being more resilient to wear and tear caused by fast charging or deep discharges.
How Do I Maintain a 12-volt Battery in an EV?
Like every car battery, these too need to be maintained to ensure the longest life and reliable performance. Keeping the battery clean, removing corrosion as needed and following proper charging procedures is key to a healthy battery.
Read about all of that and more tips to make your battery last longer in our recent blog "How Long Do Car Batteries Last?".
Shop for New Car and Truck Batteries at Batteries Plus
Batteries Plus carries a large selection of car and truck batteries for whatever vehicle you drive, from great brands you know and love. From Duracell Ultra, Optima and Odyssey to the ultimate battery experience, X2Power. We carry batteries for every power demand.
Stop into your local Batteries Plus today to see all we have to offer. Learn more about our exclusive, premium battery line X2Power by reading our recent blog "What are X2Power Batteries?".