Do ATVs and UTVs Have Alternators? (The Answer Will Surprise You)

by Matt Powell | Last Updated:  October 22, 2019

Many car owners have heard the term alternator or have had their alternator go out on them. Alternators are standard on almost all highway vehicles and it is used to power your electrical system and charge your battery so it is ready for the next time you go to crank up your car. 

You may be wondering to yourself if UTVs and ATVs have alternators to charge their battery and keep all the electronics powered and the simple answer is no.

ATVs and UTVs don’t have alternators. In fact, they use what is called a magneto system where magnets embedded on the flywheel pass over wire coils or stator to create an electrical current to power your vehicle.

Charging systems on ATVs and UTVs are different than your average 4 wheeled highway vehicles and I wanted to share a few tips and facts about them that you may not know. First you need to know a bit more about a magneto system compared to a traditional alternator system to gain full advantage of this system and be sure you keep it in tip top shape. 

I suggest you maintain your battery but anything can happen on the trail and I suggest bringing a portable battery charger with you like this one from Amazon. I will discuss this more a bit later on but I personally use this charger on everything I own from motorcycle to lawn mower to ATV. Let’s start learning about your vehicle’s charging system by watching this short video in the basics!

What Is An Alternator And What Does It Do?

So we all know what alternators are now right? Well you probably know the name and a little about what it does but let’s dive in and see just how it works before we move on to the magneto stator system. There are 3 components to a normal automotive charging system and they include the alternator, battery, and voltage regulator. All of you electrical components such as power windows, locks, dashboard instrumentation, and all your lights are powered by the alternator and battery as they work together. Alternators actually alternate current and is where they get their names from. There is alternating current (AC) and direct current (DC) and vehicle employ both types.

Engines in vehicles drive various components and one of them is the crankshaft. The crankshaft turns when the engine is running and in turn, operates the alternator allowing it to create current to power all your electronics. Alternators are generally connected to the crankshaft by a belt that is attached to a pulley. This pulley allows you to tighten or loosen the belt in order to do maintenance. Alternators produce AC power through electromagnetism. So what is electromagnetism?

It is the physics of electricity and magnetism. An interaction between electricity and magnetism, as when an electric current or a changing electric field generates a magnetic field, or when a changing magnetic field generates an electric field.

Webster’s New World College Dictionary, Fifth Edition Copyright © 2014

Alternator Components

Now that we know how an alternator works, let’s take a look at the components of one very briefly. Again this is to make sure you know the difference between the type of charging system on regular highway vehicles and UTV or ATV systems.

Most highway vehicle alternators are fairly small and can be easily installed (once all the components are out of the way) into a vehicle should something go wrong.

Housing

Alternators require a lot of direct airflow to keep them cool why they operate and this is why they have aluminum housings because it will also aid in the dissipation of heat.

Split Rings

The split ring in the electric motor reverses the direction of current flowing through the coil after every half rotation of the coil. DC motors like to reverse every time this happens and the split rings keep the current from reversing, i.e. direct current (DC).

Bearings

The bearings are little round pieces of smooth metal that are spherical shape and the rotor rotates on these. It is critical these bearings are perfectly round and do not get damaged as they keep the rotor balanced during its rotations.

Rotor

The rotor moves inside an electromagnetic system in an alternator. Its rotation is due to the interaction between the windings and magnetic fields which produces a torque around the rotor’s axis.

Stator

The stator is the stationary part of the alternator and does not turn, but the rotor turns inside the stator. As the rotor turns inside the stator, the magnetic field of the rotor turns past the stator windings with each rotation and produces an electrical current in the windings. Because of the rotation of the rotor, an alternating current is produced.

Fans

As I said before, alternators can get very hot and need to be able to dissipate heat. Along with aluminum housings, open design for better airflow, fans are used to augment the cooling for alternators.

Rectifier 

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.

Voltage Regulator

A voltage regulator controls the voltage produced by an alternator and allows it to recharge the battery. The regulator forces the alternator to maintain a voltage of between 13.5 volts and 14.5 volts.

How Are UTV And ATV Batteries Charged?

UTVs, ATVs, Motorcycles, and even snowmobiles use the same system to charge their machines and it is called the magneto stator system. The magneto used magnets that are permanently embedded into the UTVs or ATVs flywheel to produce electrical current instead of having it as a part of the alternator housing like normal vehicles.

Why Are Magnetos Used On UTVs and ATVs Instead of Alternators?

If you have been reading along then you know by now that alternators require a lot of extra cooling like airflow and vented housing to keep them running optimally while not overheating. It is much harder to get the airflow you need in a UTV or an ATV because there is no room for, or the alternators would not be in a place conducive to cooling on these vehicles.

Another major reason that an alternator is not used is because they can’t handle getting water, dirt, or debris in them because it will keep them from performing. They can also handle more extreme temperatures of up to 350 degrees fahrenheit! Designs such as engine coolant passages, oil cooling, and fan blades located inside the compartment are all used to keep magnetos operating within their specified temperature range. Off road vehicles like UTVs and ATVs are always kicking up dirt and dust or riding through terrain that is not very friendly to an alternator so another design had to be used in order to maximize the life and performance without any of the negative drawbacks that alternators pose. In fact the first ATV even came with this magneto based design because the engineers were aware of the challenges an alternator would face in day to day situations that these vehicles would present.

Magnetos are contained inside the engine compartment and sealed away from all the foreign material that may impede its operation so this style system is much more suited for us in our off road vehicle but it isn’t just offroad vehicles that implement this technology. Motorcycles do too and some of the earliest motorcycles came factory equipped this way.

When I wrecked my 2006 Yamaha R6, I sheared open the stator compartment and tore up the stator and magnets inside the compartment and had to replace them both. That bike had a generator stator and self contained alternator. That was the first time I learned about the charging systems on vehicles and why they are used the way they are.

Magneto for a Yamaha R6. See the magnets around the circle?

What Is The Difference Between Single Phase And Three Phase?

There are 2 types of charging systems and they are single phase and 3 phase. A phase in electricity means the distribution of the power load. Single phase uses a two wire system to transfer current, or power, and a 3 phase uses 3 wires. When we talk about phases, we are always referring to alternating current (AC) because DC is direct current and only flows one way.

Another key factor is that single phase is more inconsistent than 3 phase because the single phase system has multiple peaks and valleys in its power distribution and 3 phase does not. This allows more consistency in a 3 phase system giving it a more steady and constant power feed.

3 phase is also more efficient because it can transmit up to 3 times as much power by transmitting on only one extra wire. This means that the 3 phase system will use less conduction to transfer the electrical current, or power, to where it needs to go so it is easy to see why you would want to choose a 3 phase system.

How Does A Magneto Stator Work?

A stator is made up of multiple laminated bars that are wrapped up with thin copper wiring that makes each of the poles inside into a coil. Different manufacturers use different styles and pole counts for each of their vehicles so it is hard to tell exactly how many poles your setup with have without counting.

The rotor is a small wheel that is mounted to the crankshaft of the engine. It spins according to the engines rotation and speeds up the higher the engine revs. As the rotor or flywheel spins past the stator and several poles of copper wire, the magnets will cause current to flow through the coils. This generates current and with each revolution of the stator, the current will reverse and this is what creates an alternating current that is used to supply power to all the parts of your UTV or ATV.

What controls all this electrical power?

While the magneto or rotor and stator continue to create power, there has to be a way to control it. In comes the rectifier/regulator which converts this alternating current into direct current because a battery can only store direct current. The regulator controls how much power is being output to the system from the stator.

The stator and the magneto are really the same thing. Simply put the stator is the stationary, wire wound portion of the power generation system. Magneto is commonly used when describing a permanent magnet used to produce alternating current.

Which System Is More Powerful?

Belt driven alternators are inherently more powerful because they have stationary magnets with a rotating stator. This allows them to gain more speed and produce more current than that magneto system.

The magneto style is the inverse of an alternator and has magnets that rotate around a stationary stator. A magneto simply can’t supply enough amps to charge a 12V battery that will be operating your interior and exterior lights, stereo, electrical engine components, and other accessories on a larger highway vehicle.

How To Prevent Your UTV Or ATV Battery From Dying

Because ATVs and UTVs operate at lower speeds more often there is always a chance that there will be more draw on your system than the magneto can actually make up for. This is mostly true when adding extra components that put extra current draw on the system and can be the case if you use accessories like lights or a winch too long without charging the system back up. Below are some maintenance tips to help prolong and enhance the life of your battery.

Purchase A Better Quality Battery

A better quality battery will be able to handle more strain than your normal factory battery and will be able to store more juice if you get one a little bit bigger. I always upgrade my batteries after a few months of use because I don’t want to risk having a sub par battery ruining my trip.

Take Care Of Your Battery

Make sure you take care of your battery to keep the cells inside as healthy as possible. Batteries lose their charge over time, especially when they are connected to any kind of vehicle. There is a small amount of constant discharge that is happening every day and you want to keep your battery topped off, but not overcharged. 

The charger I linked in the first few paragraphs does really well at keeping your battery charged and is called a trickle charger for this reason. It stops charging once the battery is full and as soon as it discharges just a bit, the charger kicks on and charges it back to full.

Watch Your Battery Charge Levels

As I mentioned you should always keep a trickle charger on your battery when not in use but if you neglect your battery then you will notice things like dim headlights or accessory lights and you will know then that it is time to get that battery charged the right way.

Will Adding Extra Accessories Drain More Power On The Magneto Systems?

The more accessories you add to your vehicle, the more work you are asking the charging system to do. You can find a more powerful charging system for your vehicles that includes updates such as upgrading to rare-earth magnets, adding more charging coils and permanent magnets by making the flywheel a larger diameter. Also using 3 phase instead of single phase power output systems will work better. All of these upgrades will have a higher cost attached and be more susceptible to heat problems due to increased power generation.

Some alternators are beginning to be used on 4-stroke snowmobiles and will let them use more accessories than the standard magneto systems. An alternator is possible on snowmobiles because they are designed to keep air moving through the hood of the machine allowing the alternator to stay cool while producing extra power. Snowmobiles are not designed to be operated submerged in water the way ATVs and UTVs are. 

Magnetos systems are constantly being improved and, despite the lack of power compared to a standard alternator, are the best option for our powersport electrical systems.

Carry A Portable Battery Jump Starter

You never know what will happen on the trail and it is always nice to have a backup plan just in case something goes haywire. You can follow all of my tips above and still have a hiccup and end up stranded out on the trail because of a dead battery. The best way to prevent that is to bring along a portable battery pack or jump starter like this nice portable one over at Amazon. It will get you out of a pinch and back home if you happen to run your battery dead trying to get a friend out of the mud. Use the tips in this article I wrote to get you or any of your friends unstuck out on the trail. 

My name is Matt and I am the owner of DirtWheelRider.com. I want to do my best to give you all the information needed in your offroading endeavors.