ATV Battery Voltage: 9 Most Important Things to Know

The primary purpose of an ATV battery is to power the starter and other high-energy components such as a winch, hand warmers, and power steering.

To ensure the battery maintains its capacity and remains effective throughout its lifespan, it is essential to check and maintain its voltage level regularly.

This post covers what every ATV owner should know about battery voltage to ensure optimal battery performance and longevity.

• What is ATV battery voltage?
• What voltage are ATV batteries, and how many volts should they read?
• How to check the battery voltage.
• What battery voltage is too low, and what voltage is too high?
• How many volts are needed to start an ATV?

PS: The numbers provided in this post represent an average from reading the datasheets of the most popular battery brands. Deviations may occur.

What Is ATV Battery Voltage?

ATV battery voltage indicates the battery’s state of charge (SoC), measured as the difference in electric potential between the positive battery terminal and ground. 

There are several common ways to indicate battery voltage:

Nominal voltage. Nominal means “named.” A battery’s nominal voltage is a value assigned by the manufacturer that represents the battery’s average voltage during use (discharge). The value is a convenient way of indicating a battery’s voltage class (6V, 12V, etc.) and is printed on the battery casing. The value remains unchanged regardless of the battery’s charge level or operating voltage.

Open Circuit Voltage (OCV or Voc). A battery’s OCV indicates its measured resting voltage when it’s not delivering or receiving any power. There is no load connected, no current being drawn, and the battery is not connected to a charger. The OCV of a fully charged battery is typically five to seven percent higher than its nominal voltage. 

Closed Circuit Voltage (CCV) is the operating voltage and indicates a battery’s measured voltage during discharge or charging.

• Discharging is when the battery is under load, and a current is drawn. CCV during discharge is lower than OCV due to internal resistance in the battery.
• Charging is when the battery receives power from an external power source such as a charger or the ATV charging system. CCV during charging is higher than OCV.

What Voltage Are ATV Batteries? (Nominal Voltage)

A conventional ATV battery has a nominal voltage of 6V or 12V, depending on the vehicle’s electrical system. 6V batteries are most common in some youth models, while 12V batteries are the most common type in adult-sized ATVs.

Only use a battery that matches the voltage rating your ATV requires. Using a battery with the wrong voltage can harm the ATV’s electrical parts and wiring.

• If the ATV has a 6V system, you should only use a 6V-rated battery.
• If the ATV has a 12V system, you should only use a 12V-rated battery.

ATV batteries come in different types based on battery chemistry. Regarding nominal voltage, lithium-ion batteries differ from lead-based batteries such as lead-acid, AGM, and GEL batteries.

• A lead-based battery has a nominal voltage of 2.0V for each cell, giving a 6-cell battery a nominal voltage of 12V.
• On the other hand, lithium-ion batteries have a nominal voltage ranging from about 3.2 to 3.2V for each cell. That is why a 4-cell lithium-ion battery typically has a nominal voltage between 12.8 and 14.4V. 

When upgrading from a lead-based to a lithium-ion battery, ensure your chosen battery is compatible with your ATV. Most battery manufacturers provide a compatibility table. 

Related: How to Replace or Install an ATV Battery; Step-by-Step

Here are a few ways to know what voltage class your ATV is designed to run on.

• Look for labels on the existing battery. All batteries have a label indicating their nominal voltage.
• Refer to the owner’s manual. You’ll find information about battery voltage in the spec sheet or under the chapter about battery maintenance.
• Ask the dealer. If you are still unsure what battery voltage your specific ATV uses, ask the dealer rather than risk installing the wrong type of battery. 

Related: What Do ATV Battery Numbers Mean?

The Recommended Voltage Range for ATV Batteries

A battery’s actual voltage varies between battery types and is usually higher than the nominal voltage.

A fully charged 12V conventional ATV battery should read between 12.6 and 12.9V at rest, while a fully charged 6V battery should read between 6.3V and 6.45V.

Most ATV batteries are Flooded Lead Acid (FLA) or AGM. Lithium-ion batteries have higher performance but are more expensive and operate at a higher voltage than conventional batteries.

When measured at room temperature, a battery’s voltage can be used to estimate its state of charge. The tables below give a more detailed indication of normal voltage levels for various battery types.

How Many Volts Should a 12V ATV Battery Read?

How Many Volts Should a 6V ATV Battery Read?

Typical ATV Battery Voltage When the Engine Runs

When you start the ATV, the battery voltage increases by the charge from the ATV charging system. 

When you start the ATV, the battery voltage rises due to the charge it receives from the ATV’s charging system.

ATV battery voltage when the engine runs is typically between 13.7V and 14.7V, depending on the battery type and the bike’s charging system.

Battery voltage above 14.7V measured with the engine turned on indicates overcharging, usually caused by a faulty voltage regulator. 

How to Check the Battery Voltage

To determine if your ATV battery has sufficient charge or needs recharging, you should check its actual voltage. For this, you can use either a voltmeter or a basic multimeter.

Here’s a simple guide on how to read the battery voltage using a multimeter:

1. Turn the ignition off: Open circuit voltage is measured with no load on the battery.
2. Access the battery: Remove any plastic covers to access the battery, usually located at the front of the ATV or below the seat. 
3. Set Up the Multimeter:
   • Attach the red positive probe to the “V” port and the black negative probe to the COM port.
   • Turn your multimeter to the setting for an open circuit voltage reading. This is usually marked as 20 V DC (v⎓) if it’s a manual multimeter or ‘V’ with a straight line if it’s auto-ranging.
4. Connect the Multimeter:
   • Attach the multimeter’s red probe to the battery’s positive (+) terminal.
   • Connect the black probe to the negative (-) terminal.
5. Read the Voltage: Observe the reading on the multimeter’s display. This number is the current voltage of your battery.
6. Interpreting the Results: Refer to the tables above to determine its state of charge.
   • 100 %: No action required.
   • 75% to 100%: It might need a slight charge.
   • 50% to 75%: Needs a full charge.
   • 25% to 50%: Needs a full charge.
   • 0% to 25%: Needs a charge with a desulfation charger.

Remember that even if a battery shows a full charge reading, it doesn’t necessarily mean it is in good condition.

Related: How to Test an ATV or UTV Battery. Good, Reduced, or Bad?

What Battery Voltage Is Too Low?

A conventional lead-acid or AGM 12V ATV battery that reads below 12V at rest is too low and needs a charge. When a battery reads below 11.5V at rest, it is considered dead and needs to be replaced.

Similarly, A 6V lead-acid or AGM battery must be charged if it drops below 6V to prevent damage. When a 6V battery drops below 5.8V, it is considered dead.

Note that a 12V battery may drop below 11.5V briefly under load, such as when starting the ATV. However, a healthy battery should maintain a minimum of 9.6V even under heavy load and jump right back up when the load shuts off.

A Lithium-Ion battery can manage the occasional drop below 12.9V, but if the voltage drops below 12.5V, this may cause permanent damage and shorten the battery life span.

What Happens When the Battery Voltage Gets Too Low?

When the battery voltage drops too low, it doesn’t hold enough power to start or keep the ATV running and will begin losing its potential capacity due to a process known as battery sulfation. 

Sulfation is a chemical process where sulfate crystalline deposits build up on the battery’s lead plates from being in a discharged condition or from being exposed to oxygen. The rate of sulfation increases as the voltage decreases.

Optimal Charging Voltage for ATV Batteries

Charging a battery with too high of a voltage may cause permanent damage to the battery and the ATV’s electrical system and components.

Different battery types must be charged at different voltages to prevent overcharging. Some battery types are more prone to overcharging than others. Lithium-ion batteries are especially susceptible to damage if you use an incorrect charger or charge them at a voltage that’s too high.

A high charging voltage can occur if the ATV’s voltage regulator becomes defective or you charge the battery using the wrong type of charger. 

Always ensure the charger you use is compatible with your battery type and that you use the correct charging mode. Refer to the battery spec sheet for proper charging voltage.

Typical charging voltages by battery type:

How Many Volts Is Needed to Start an ATV?

An ATV typically needs a minimum battery voltage of 11.5V to 12V to start. Turning the engine usually requires at least 12V or more in cold weather. 

A battery that can barely start the ATV likely has a too low voltage and needs a charge to prevent reduced battery service life. 

Wrapping Up

As you’ve probably realized by now, no one answer fits all regarding battery voltage. Hopefully, this post gave you a better understanding of why battery voltage matters and what you can do to ensure you get the most out of your ATV battery.