Flow Racers is a reader-supported site. Purchases made through links may earn a commission.

Why Do Supercars Need Trickle Chargers?

If you’re an observant person, you may have noticed that in movies and car showrooms, supercars tend to have a small box with a wire going to their battery, called a trickle charger. No matter the manufacturer, every supercar needs a trickle charger.

Supercars need trickle chargers to keep the battery healthy. Supercars have lots of sophisticated electronics constantly drawing power, and they are usually not driven regularly. Because of this, their batteries lose charge quickly and eventually die, even when parked. Trickle chargers prevent this.

This is an oversimplification, of course. There is a lot of nuance, miscommunication, and conflicting information out there regarding trickle charging that this article will acknowledge and dispel. After all, if you’ve spent a small fortune getting yourself a supercar, you’ll want it to last!

What Is A Trickle Charger?

A trickle charger is a battery charger for a car. Much like with your phone or laptop charger, it charges things. Supercar trickle chargers are designed to provide your car with a small but steady flow of charge while your car is in your garage to preserve the battery.

Traditionally, a “trickle charger” was also called a dumb charger. They were compared to “smart chargers,” and the main difference between them is that a trickle charger did not have an off button. You would plug it into your battery and plug it out when you had enough charge. A smart charger often had a microcontroller attached to it that knew when to turn off so the battery did not overcharge.

Different Terminology

Terms like “battery tender” and “battery maintainer” are also thrown around, but these are just market terminologies for chargers. If you’re a fan of electronics, there’s a huge difference between a smart and a dumb charger, but for marketing purposes, battery tenders are trickle chargers with regulators and battery maintainers are smart chargers that maintain current flow.

So now that you know that the term “trickle charger” has become an overarching name for a variety of different things, what connects them together? The hint is in the name itself. It produces a low ampere charge that trickles into the battery over a long period of time. In recent years, people have begun to differentiate and insist “trickle chargers” only be used to describe dumb chargers.

RELATED ARTICLE Do Supercars Depreciate?

How Does A Trickle Charge Work?

A trickle charger works by providing your supercar with a small, steady flow of charge to prevent the battery from discharging too much while your car is in your garage. Some trickle chargers may provide a constant charge regardless of the battery’s charge level, while others turn off automatically.

To understand how a trickle charger works, we must also understand the basics of batteries. Regular cars have lead-acid batteries, but supercars tend to have lithium-ion batteries, which contain the charge. This charge is used to start the car, causing the first sparks that ignite the fuel in the engine. Before the engine turns, any device in the car utilises the stored charge in the battery.

This means if you’re sitting in your car while it is not idle and rolling your electric windows up and down or listening to music, you are drawing power from the car battery and not the engine. Between this usage and how car batteries tend to discharge slowly anyway, you need a way to keep your battery health up when the car is not running.

When You Start The Engine

Once the engine starts, it’s a different story. The alternator kicks in, which uses the engine power to create electric current to charge the battery. It’s a circular loop, so whatever charge is used to start the car is restored by the engine. But what happens when you do not have enough charge to even start the car? What if there isn’t enough power for the spark plugs to go off?

That’s where the trickle charger comes in. It’s a tool that helps you charge your car battery outside of the internal alternator loop described above. It throws current into the battery until it’s full and can’t take any more. If the trickle charger is a battery tender, then it will notice that current isn’t flowing as easily and turn itself off.

If, however, it is a dumb charger, it will keep going and cause an overcharge. The charger doesn’t realise the battery is full and continues supplying it with a current that will damage the battery and could potentially cause an explosion depending on the type of battery. Most supercars have a lithium-based battery, which is resistant to an overcharge, but there’s still a risk.

Why Do Supercars Need Trickle Chargers?

Supercars need trickle chargers for various reasons. Often, your supercar may have features that constantly run in the background, even when you’re not driving your car. The other main reason is that you may not drive your supercar often enough to keep the battery charged.

Even when your supercar is doing nothing, it is still drawing considerable power from the battery to maintain certain features. You may have various security features for example, and they may always be running in the background, slowly draining your charge. Normal cars may have similar features, which is why cars can’t be left too long without starting them.

They Often Aren’t Driven Much

The other reason this is important is because supercars are not usually taken out to drive every single day. Their mileage is important and is often kept as low as possible, and every time they are taken out for a drive, you risk damaging them either in an accident or somehow else. That’s why a lot of supercars are kept in the garage for weeks at a time.

This means that your supercar is likely going to be sitting still, undriven, for a fairly long time. If it’s an older model with a lead-acid battery, it could self-discharge down to dangerous levels rapidly. More recent models of supercars tend to have lithium-ion batteries, like the McLaren 720S, whichis far more stable and has slower discharge.

Lithium-ion batteries also have a fail-safe in case of overcharge. They tend to cut off ionic flow to the battery when it is full to prevent damage, but it’s no replacement for turning the charge off when it is full. When you’ve put as much time and effort into what’s more or less a depreciating asset, you want it to last for as long as possible. Trickle chargers can help you do this.

Do All Supercars Need Trickle Chargers?

All supercars need a trickle charger or battery tender. It’s suggested to have both a tender and a maintainer if possible, because trickle chargers work well to get your battery up to full charge, but it isn’t the best way to keep it there.

Battery maintainers have dynamic voltages, and so they prevent the battery cells from discharging by varying the voltage fed into them. But if you don’t want to get a maintainer and want to simplify car-care by keeping only one charger, a decent trickle charger with a robust regulator would get the job done.

Choosing The Right Charger

Supercar manufacturers often have a trickle charger for sale that is designed with their specific batteries in mind, so it’s usually better getting one of them than choosing the first one you see online.

Certain supercars are special and have different needs. One noteworthy example is Lamborghini’s Sián, which does not use conventional batteries but instead uses something called “supercapacitors” instead of the lithium batteries conventionally used. These are charged similarly and have the same concept as conventional charges but require a bit more deliberation when keeping them topped off.

What Happens If Your Supercar’s Battery Dies?

If your supercar’s battery dies, it will normally cost at least a few hundred dollars to get your battery replaced, but it can go into several thousands of dollars as well, depending on the make of the car and the battery type. If your battery dies, it is difficult to recover.

Your engine won’t start without some charge in your battery, and getting it replaced is the only actual solution. Recharging the battery after it has died will allow you to get your car running, but with the delicate electronics and sophisticated circuitry going on underneath, it’s a dangerous game to play. Instead of a dead battery, you might end up dealing with fried circuits.

Preventing Your Battery From Dying

This is why it’s so important to always have a trickle charger in your supercar garage. It will make sure that your battery never dies because every time it drops to a certain level, it will charge it back up. This kind of loss is normal, and batteries don’t get damaged this way. Regardless of the type of battery, the manufacturer would have the correct charger available.

If you did have an appropriate trickle charger but your battery died anyway, there are a few things that might have happened. It’s possible that your alternator is damaged, so when the charger isn’t connected and the battery relies on the engine to keep itself topped off, it’s simply not working. This would likely happen while driving rather than when starting the engine up for the first time.

If it happens in the garage, then there could be an issue with the wiring or the trickle charger itself. In either instance, the damage has already been done to the battery and it will need to either be recovered or replaced. If you’re keeping a supercar, you probably have the funds to get it replaced, which you should do. It’s healthier for the battery that way.

What Trickle Charger Is Best For You?

Your needs will vary depending on the kind of battery that you have. Most of the time, you will get a charger from the dealership where you acquired your supercar, but there are exceptions. In this case, you can go out of your way and buy your charger separately, or you could go to the source. Some companies often rebrand CTEK chargers as part of the package deal.

This means that the McLaren battery tender that the dealership gives is just a rebranded version of a CTEK charger. Lamborghini does the same, as many companies do. As such, you can go directly to CTEK to get your appropriate charger. They sell package deals for battery care depending on the brand, as McLaren batteries and Aston Martin batteries have different needs.

It Depends On What You Need

High grade battery maintainers are capable of outputting just as much current as a battery tender, which means that if you’re committed to keeping your battery healthy, getting a high-grade battery maintainer is the best solution. Of course, if you use your supercar frequently, a simple trickle charger would also get the job done. It all depends on your specifications and your needs.

Lamborghini’s Sián uses supercapacitors instead of traditional batteries, but it still essentially functions the same way. Larger batteries would need a heavy-duty trickle charger, while smaller ones could do without it. The specifications of your supercar battery dictate exactly what kind of charger would be best, but odds are they would all be available to you at CTEK.

What Happens If Your Supercar Battery Overcharges?

A lot of things can happen if your supercar battery overcharges, depending on what kind of battery it is. You should prevent it at all costs, as an overcharged battery is never a good thing. For this reason, no matter what car you have, you should never use a dumb charger on your battery.

Lead Battery

A lead battery is full of water and electrolytes. It is here that the charge is stored, and when the battery is getting too much current, far more than it can handle, it does something interesting. It begins to heat up the water it uses as storage. If your battery is perfectly sealed, this can cause a pressure build up and eventual explosion.

If your battery begins boiling off, that’s a visual indication that your battery is dying in front of you. Dead batteries need replacement, but overcharged batteries can cause a disaster that will destroy nearby components. It’s frustrating enough dealing with dead battery problems – you don’t want to deal with explosive battery problems.

Lithium Battery

Lithium batteries are a little more sophisticated. Since they do not store the charge in chemical energy but as lithium ions, they are able to store things far more efficiently and are designed to be rechargeable. Alkaline or other chemical batteries are not. When charging, the batteries pull the ions to one electrode, and when providing power, they let the ions move to the other electrode.

It is a standard and has become a safety requirement that lithium batteries come with built-in protections against overcharge, whether it’s a surge charge or a slow charge. There are mechanisms that cut off the flow of ions from the electrodes and keep them from overcharging. It is an elegant solution, but it’s not perfect. Lithium batteries are still susceptible to overcharge.

Lithium batteries are resistant but not invulnerable. Overcharging them can cause unstable lithium ionisation in the battery, hot air venting from cells, and can cause both fires and explosions. Samsung was in hot water because of their lithium battery disaster in 2016 simply because they had poor design and were prone to overcharge.

Supercapacitor Battery

Supercapacitor batteries are less dangerous when overcharged. In other examples, when batteries were overcharged, you could tell immediately. Lithium batteries hiss from the thermal packets, lead batteries boil, but supercapacitor batteries will break the circuit. It will be as if you cut the wire of a circuit or turned off the power.

It’s not entirely immune, because if the batteries are overcharged and do not have surge protection, the current will travel through open air. This would be a catastrophe, but it is far less likely than battery overcharge or lithium overcharge. While currently rare on supercars, this could be a common feature in the future.

Final Thoughts

Supercars need trickle chargers to keep the battery healthy. Because supercars often have security features that run even when the car is off, and the cars are often driven infrequently, the battery is susceptible to draining when left in a garage for a long time, and trickle chargers prevent this.