EV World: The 12-volt lifeline of electric vehicles

How lead-acid batteries power the hidden systems in EVs

While much of the talk around batteries in the world of electric vehicles has centred around lithium-ion, a proven tested technology looks to be the key to unlocking the full potential of EVs.

Indeed, a more traditional technology continues to play a critical role in keeping these high-powered vehicles going: The 12-volt lead-acid battery.

Automotive repair experts will note that it’s commonly forgotten that an EV still has a 12-volt battery helping power the vehicle. The vehicle’s sophisticated network of auxiliary systems depends on the humble lead-acid battery to manage everything from security features to critical safety functions. These unsung battery heroes silently ensure that when the vehicle owner approaches their EV that their key fob works, the security system activates and the vehicle’s fundamental electronic systems remain operational.

Bryce Gregory, director of strategic product technology at EnerSys, offers a glimpse into this technological ecosystem. With over a decade of experience in energy storage systems, Gregory explains that the 12-volt battery isn’t just a holdover from traditional automotive design — it’s a deliberately engineered solution that continues to be essential in our increasingly electrified automotive landscape.

As EVs move more into the mainstream transportation consciousness, understanding these intricate technological dependencies becomes crucial. The story of the 12-volt battery in electric vehicles is less about replacement and more about intelligent integration — a testament to the enduring power of proven technological solutions.

EVW: 12-volt lead-acid batteries are taking on an important growing role as we’re vehicle electrification. Can you explain the role of these batteries in the EV market?

BG: The biggest place that I see them used today is in the EV space is providing key off-type power on a typical car. You would recognize that as the ability to lock and unlock your doors or have a security system through your key fob. And, frankly, those systems are still basically built in 12-volt architectures today and for pretty much every vehicle on the planet.

And in those 12-volt applications, those are critical to starting the vehicle. In EV applications in particular, charging a 12-volt battery is actually kind of complicated, because you don’t have an alternator spinning every time the vehicle starts up.

EVW: What kind of challenges does that present for our industry and making this technology more convenient for consumers?

BG: I don’t see a lot of changes in that space because of all the components that are developed — because of the reliability of those components, and, frankly, the low power demand of those. One of the challenges you see in that space, though, is that traditional automotive batteries — a lot of them — aren’t really designed to cycle in that manner, to be able to get drawn down and then recharge. In most lead acid battery chemistries, you find in cars today, you run into them and they’re dead, a lot of times, because they’ve sat for too long or there’s some sort of parasitic drain

And there are batteries out there that are really designed well to handle that application, but they’re not typically designed well to go in a car, to be able to handle the shock and vibration and all the other things associated with it.

This application in the industry is called auxiliary batteries. We’ll call them low-power cycling-type applications. And improving automotive grade batteries to be able to handle auxiliary applications is really a is what’s happening in the automotive space. You see it not just in electric vehicles but in hybrid vehicles, especially the Toyota Venza — that has a group 47 auxiliary battery that doesn’t crank the engine over, but it does all these other applications and does it well and reliably. But that’s a really big battery for doing those little bit of things that it does do and do well.

So you see the downsizing of that battery and improvement of the electrochemistry and its ability to handle shotgun vibration is what’s happening in the lead space today.

EVW: How do these improvements help or influence the growth of the EV market?

BG: Certainly, as the EV market grows, that’s one thing that — if you look at any sort of news where people complain about EVs — that’s one of the things that people complain about. “Oh, my battery died and I couldn’t do anything. I couldn’t open the door, I couldn’t do all these things.” So that is certainly sort of a roadblock in this space to the average consumer — that they can’t do the things that they would historically be able to do when they have the same kind of problems that they might normally have had.

So getting rid of those roadblocks to be able to improve the technology to make sure it works through those applications will certainly open doors for the EV market.

“But making that battery last as long as the application and preventing the remanufacture or manufacture of multiple other products, I see those as great opportunities to be very environmentally friendly.”

EVW: How do we get rid of those roadblocks? How do we move them out of our way so that it’s easier to work with?

BG: Well, certainly picking the right electric chemistry, the right design of battery for the application. I work for Odyssey Battery, and it’s a battery that’s AGM technology, but it also has additional advances. One of those additional advances is that it uses a pure-lead architecture, meaning we don’t add calcium to the grids or to the pace mix or anything like that, to be able to make the battery. And when those are used, typically, it’s made to make the grid stronger. And what we do is we engineer the battery with compression so the case actually provides that strength.

By not using calcium or antimony in the structure of the battery, we’re able to avoid sulfation oxidation of the battery, and oxidation of the battery. So not that those things don’t happen still, but they happen to such a lesser degree that you’re able to discharge that battery lower, and it’s able to recover better.

But technologies like that, that’s not the only one. There are many technologies that can improve the cycle life of the battery and its ability to withstand not being fully charged for a longer period of time or surviving at a lower discharge level, which is what’s happening in this application with EVs. And the batteries that are being bought off the shelf and put in a lot of these cars today just aren’t really designed for it.

So picking architectures like what we do with Odyssey battery and what other companies are currently in development on will improve their abilities to be able to handle those applications.

EVW: Why continue to use lead and these 12-volt systems?

BG: One of the big reasons that you stick with lead in addition to — these sound like simple things but there’s a whole bunch of other — we’ll call it, 12-volt systems in a vehicle that are important to the safety of the vehicle. Teslas have automation on them —  they’re able to basically drive themselves. When you have automation on a vehicle, you have to be able to essentially operate safely, stop safely. And, frankly, the steering systems and the braking systems on these vehicles need to have backup energy. That really can’t be the primary energy storage. The motive power battery in the vehicle needs to be a separate system to make sure that when something fails in that system, the vehicle can be safely brought to a stop.

And that’s one of the reasons that lead is selected in those applications, predominantly in the world, is that people, engineers, companies, service providers, etc, understand that what lead batteries basically do, at least to enough of a point where they can service them and they can replace them easily, and you’re not waiting days, weeks, months for replacement part, etc.

So there’s a host of reasons why lead batteries are still used in these electric vehicles, and why 12-volt systems are still used in these vehicles. And that’s really to support not only the simple, basic low power stuff, but also these critical safety systems.

EVW: How do you see this traditional 12-volt lead-acid battery system evolve alongside the lithium-ion systems that we’re seeing more and more of nowadays?

BG: That’s a really good question. And frankly, I think there’s a lot of companies out there trying to figure out what that means. In that market space, you have two different sides to that argument. You have the part suppliers and, typically, they try to work in concert to bring the best solutions. The other issue that you see today is the actual availability and not only the cost of using a lithium battery to replace it, but the weaknesses of that system.

So some of the weaknesses of traditional lithium systems, or it might not be so traditional but they don’t really function well in cold. So if you have a lithium battery in a vehicle to support these systems, you might have to heat that battery. You might have to do some other things that actually require you to use energy that you wouldn’t necessarily need in another chemistry. As well, the supply chains for lithium batteries are stressed and will be stressed for quite a long time. The additional mining of minerals and required elements for lithium batteries, those supply chains are — with the move to EVs and hybrid vehicles — are really consuming a tremendous amount of those resources.

So not only is there supply chain constraints that will keep lead in play for a very long period of time in these applications on vehicles, both EV and non-EV, but I don’t see a future where — we’ll call it other lithium technology or lithium-like technologies — will likely replace lead acid batteries.

“The motive power battery in the vehicle needs to be a separate system to make sure that when something fails in that system, the vehicle can be safely brought to a stop.”

EVW: Can we develop lithium to provide the benefits we see from lead acid?

BG: Those take a long time to develop. There are things in queue today that have gone through the university levels or the corporate levels and have been proved out that they can do these things. But now you have to be able to manufacture them. You have to build a supply chain for them. And you may or may not be aware, but lithium batteries go through basically a full evolution every 18 months. So it’s really hard for manufacturing to keep up with the changes in the technology. So there are a lot of things happening in that space, because it’s a rapidly growing market, as well as the advent of similar technologies like sodium batteries.

So the stability of lead, and the availability of lead — and not only those things, but also the nearly 100% recyclability of lead — are an important factor in these markets and in the replacement markets in the use of the product and the lifecycle cost of those products. I don’t see 12-volt architectures dramatically dropping off in the next decade. There are going to be companies that test the waters. Tesla is already, currently testing the waters with a 48-volt system on the Cyber Truck — but that truck does have a 12-volt system. Granted, it’s not battery supported, or at least as far as I’m aware. So it’s not that it’s impossible, but there are challenges to it — and those challenges are things that people definitely don’t necessarily want to deal with.

And then add to it the supply chain concerns. One of the big things about lithium batteries is there are ‘forever plastics’ in them. It’s in the electrolyte; it’s in other parts of the products and not easy to get rid of. And frankly, in lead batteries, you can build lead batteries without those ingredients. Today, many companies do so. There’s a strong concern globally for what’s called PFAS. These are a really significant concern with the current state of lithium technology today.

So I do see a future where likely lead and also likely lithium batteries aren’t really used that much. Where other technologies that will be developed in the near future, or are currently are in the beginnings of the development cycle, may replace those technologies significantly when they also meet the needs of the wide temperature range and the safety related aspects, as well as the reliability related aspects.

EVW: So these technologies will complement each other rather than compete to be the outright only choice?

BG: I would say they’re complementary, especially in the EV space, and especially in things that need a whole lot of energy and need a whole lot of cyclability. Lithium has some advantages, but in applications that don’t need that much and maybe need a little lower price plate product but carries a strong reliability that will work together with those technologies to make vehicles work — and work well — for the foreseeable future.

EVW: Where can lead perform better and help fill the void that lithium can’t?

BG: Well, cold climate is one. But as you’re aware, most companies don’t build products for distinct environments. Like in the United States alone, if you sell a vehicle — and we’ll call it a commercial truck just to make it real simple — that truck could be operating in Arizona one day or one week and it could be operating in Alaska the next. So it’s very difficult to segregate products in such a way based on the climate.

So having products that work in all the climates that the trucks will see, or are likely to see, is what you’re going to see on vehicles, I think, for quite a while — until some new technology that surpasses and doesn’t share the weaknesses of any of the products that are on the market today comes into play

“So there’s a host of reasons why lead batteries are still used in these electric vehicles, and why 12−volt systems are still used in these vehicles.”

EVW: What innovations do you see in the 12-volt battery space that could further enhance their roles in the EV market?

BG: Certainly building, taking what we learned in lithium batteries and applying it to lead acid batteries — in terms of battery management systems and things like that — is one way that these products will improve over time. Take that technology that’s been developed for other chemistries, but applying it to lead to improve it. And one of those ways is to improve how batteries charge. Just the charge rate and the exact way a battery is charged — in terms of what voltage is applied where, how much current is applied where — can have a dramatic effect on the life of that battery.

And certainly, you know recycling is great. Being able to recycle a battery at near-100 per cent type numbers is a great thing. But making that battery last as long as the application and preventing the remanufacture or manufacture of multiple other products, I see those as great opportunities to be very environmentally friendly. And that exists within the lead space today and is improving on an annual basis. You see batteries that can last longer, that use more recycled material.

And then add to that, other technologies, like some different separators, different carbon additives — simple, elemental, basic stuff that you can add to the batteries — that make them perform in partial state of charge, conditions, as well as all the different cycling and temperature, shock and vibe instances that we see. I see those things all being a benefit to the technology roadmap and to meet these future demands that we see in this space.

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This article originally appeared in the Summer 2025 issue of EV World