Should You Switch Your Lead-acid Car Battery to a Lithium Battery?
Well, yes.
Yes, you should switch your car battery from lead-acid to a lithium (LiFePO4) battery.
It’s simply a far, far better technology.
But.
A more relevant question is: “Can I switch from lead-acid to lithium?”
And that is the more complicated question.
In this article, we’ll discuss whether you can, and TLDR, spoiler alert, the answer is:
“No, probably not. Not yet”.
We’re obviously talking about petrol/diesel cars, not electric cars (Teslas and suchlike) which, of course, already use lithium batteries, and, indeed, must use them.
Can You Switch to an LiFePO4 Car Battery?
As we said in the introduction, you most likely can’t, even though you should.
The vast majority of LiFePO4 (lithium iron phosphate) batteries sold in the UK are leisure batteries for motorhomes, campervans and suchlike. Or for solar applications.
Varta, a huge automotive battery manufacturer, also make lithium-ion batteries but they’re for “caravanning vehicles and boats”.
lithium batteries are vastly superior to lead-acid batteries in pretty much every way, and we’ll discuss exactly why. They’re also, in 2026, very, very safe; with highly sophisticated Battery Management Systems (BMSs) that prevent things like overcharging and overheating extremely effectively.
Why are lithium batteries better than lead-acid batteries?
The newest type of lithium batteries are a revolution, not mere evolution compared to lead-acid batteries.
It sounds like hype or bombast to say that, but it’s really not.
Let’s see why.
Longevity
The latest 2026 LiFePO4 batteries are rated for 6000+ cycles, while a good quality lead-acid battery is good for around 400 cycles or so.
You do the math…
Okay, we’ll do the math. That means it’ll last around 15x longer.
Not 15% longer. 15 times longer.
Starting Power
The starting power comparison is something of a… well, a non-starter. The difference is pretty huge.
A 40Ah lithium car battery could be around 1500CCA (Cold Cranking Amps). CCA, by the way, is the standard way of measuring the starting power of a car in cold weather (-18°C, to be precise).
Meanwhile, a 40Ah lead-acid battery may typically be around 300 to 400CCA.
Ability to handle discharge
AKA ability to deal with states of low charge.
Lead-acid batteries can’t really hack being deeply discharged. That’s why your car won’t start if you don’t drive it for a few weeks.
That’s simply not the case with lithium batteries, which can handle several months without being used with no issues at all.
Ability to handle cold temperatures
All batteries have reduced power in cold temperatures.
But many of the newest types of lithium battery can still work down to -20°C, at least for most applications.
And some premium models of LiFePO4 battery come with an in-built heating function, designed to give you starting power in extremely cold temperatures.
Weight
Lithium batteries are very much lighter than lead-acid batteries.
Most high quality lithium batteries are half or even as little as one-third of the weight of the equivalently sized lead-acid battery.
And this is a gap that seems likely to grow.
Each year, lithium cell makers are getting better at packing more power into smaller cells.
You Can’t Normally Use An LiFePO4 Battery In Your Petrol or Diesel Car
Why?
We’ve just read how much better modern LiFePO4 batteries are than lead-acid.
And they’re very widely available for other uses.
So why can’t we replace lead-acid batteries with lithium batteries?
Because the big car companies are not ready for it.
So they’re not selling cars with lithium batteries in them.
Change resistance
Their cars have long been built for lead-acid batteries, be they typical lead-acid, AGM or EFB (which are still varieties of lead-acid).
They’re not so eager to change everything to suit lithium.
I know what you’re thinking:
“but most of these companies are now making electric cars, and have been making hybrid cars for quite a long time now, right?
But those are a new category of cars, and their whole internal automotive power and electronics system is built for lithium batteries, from the ground up.
Political economics plays a large role here. Some very large automotive companies make lead-acid batteries. And even those that don’t have very close relationships with those that do.
They’re certainly going to put some pressure on car makers to make sure lead-acid batteries are the battery of choice for as long a time as possible.
Remember we said that 6000+ cycles are now possible with lithium batteries?
That means it could last as long as 10-15 years. Lead-acid batteries last maybe 3 to 5 years at the most.
That’s a very significant loss of sales revenue from replacement car batteries that would be lost if lithium batteries became the norm.
Geopolitical reasons and supply chain dependence
Using lithium batteries also means relying on supply from China. In an uncertain political climate, that’s a major risk that big companies are not that keen to take quite yet.
China, in case you don’t know, is practically the only place you can get lithium batteries from.
Governments are also involved, and of course will adopt regulation, duty and tax directives to suit political agendas.
For example, the UK automotive market would become very dependent on lithium supply. That’s going to be quite a lot of different industries dependent on one supply.
For these reasons, you can imagine it’s going to be a long process.
But it’s not just that automotive companies are resistant to change. It’s also cost considerations.
LiFePO4 batteries are still much more expensive than lead-acid batteries, as a one-time purchase.
Electric cars are mandatory by 2035 in the UK
Does it make sense to even start the long and slow process of developing cars that are ideally suited to use lithium batteries, educating the public about them, or developing lithium batteries that work for petrol-diesel cars when the UK has plans to make electric cars mandatory in less than 10 years.
That said, it will only be illegal to buy new cars that are petrol/diesel. You can expect the existing market for used petrol and diesel cars to continue for easily a decade, and likely even longer than that.
And there are those who think that the 2035 deadline could be extended by several years or even overturned entirely.
Research suggests the lead-acid battery market in the UK is growing, not declining. Read from that what you will about the future of car batteries.
Are LiFePO4 Car Batteries even available (for petrol/diesel vehicles)?
Yes, they are.
The market in the USA for LiFePO4 batteries for gas cars (as they call petrol cars) and diesel vehicles is more developed than here in the UK.
But, even there, these batteries are typically intended for race cars and performance vehicles.
You can check out one example here; an American company called Antigravity Batteries, has a UK branch selling lithium car batteries.
Only drivers of those kinds of cars would value such a costly investment to get the vastly superior power to weight ratio that lithium batteries provide.
Is there currently demand for lithium car batteries?
The data suggests there is.
Here’s the trend line, showing how many people have googled “lithium car battery” in the last 5 years, to 2026.
Data source: Google Trends (https://www.google.com/trends).
It’s not surprising.
It’s a product that does a much better job than the alternative:-it lasts much longer, is more powerful, and starts your car better in the cold.
But the machinations of the economic, industry, and geopolitical worlds; all cogs that work in tandem, mean that it could be a while before they’re widely available for petrol and diesel cars.
Lead-acid to LiFePO4 Battery Summary
Hope that answers your questions.
It’s most likely that you can’t easily replace your current lead-acid car battery with a lithium (LiFePO4) version.
Auto companies don’t seem to currently have an appetite to give you that option. There are numerous political and economic reasons why that is, such as the vested interest of auto companies in the existing lead-acid battery market, the over-reliance on China for lithium, and impending regulatory change.
All that said, if you’re really keen to find a lithium battery for your car, you can.
You just need to make sure it’s actually a starter battery that is compatible with petrol or diesel vehicles, and of course, that it fits your car.
But, for the time being, it’ll be very costly. You’ll have to really want to invest in it.