ATV and UTV batteries are considered consumables that go bad over time due to sulfation, bad cells, poor maintenance, or simply old age. Before you go ahead and buy a new battery, it’s a good idea to test the condition of the one you have. That way, you know you are not wasting your money when other issues may be the real cause of your poorly performing battery. 

No single test will troubleshoot all of the potential problems a battery can have. But by going through the steps in this little guide, you will cover most aspects that may be causing issues.

These are the tools you will need:

  • A battery charger
  • A multimeter or voltmeter
  • Optional: A consumer-grade battery load tester

Caution: For all of the testing in this post, we recommend that you use safety glasses and gloves.

Step 1: Make sure the issue is battery-related

You may just have found that your ATV does not want to start, and you suspect that it’s caused by a dead battery. Keep in mind that there is a range of other reasons why your ATV seems completely dead or will not start.

Before spending too much time testing the battery, we recommend you make sure there are no simple solutions like forgetting to turn off the kill switch, not having the gear shifter in “park” or keeping the brake lever activated. Such mechanical safety features that may prevent your ATV from starting vary from model to model. Here is a complete guide for when an ATV won’t start.

Step 2: Visually inspect the battery for defects

Before you begin testing, it’s a good idea to inspect the battery visually. You may need to remove the battery from the ATV for a proper inspection.

If you notice any of the following defects, there is a good chance your battery is bad beyond repair. Replace it with a new one, no further testing is necessary.

Bumps or bulges in the outer casing

A visible bulge may be a sign of overcharging. Smart chargers shut off automatically when a battery is fully charged. 

Manual chargers, on the other hand, need to be monitored and turned off manually as soon as the battery reaches a full charge, or you face a risk of overcharging the battery.

Loose or broken terminals

The terminals should feel solid and not move even slightly. A loose terminal may create a potentially dangerous short circuit.

Melted or burnt plastic near the terminals

When a loose terminal short circuits, the battery will discharge all of its power immediately. Such a rapid discharge creates a lot of heat that can melt the plastic or make it catch on fire. A direct short like this can sometimes even cause the battery to explode.

Visible cracks or ruptures in the outer plastic casing

Battery casings are tough but may crack open from impacts, mishandling, or if the battery has frozen. A cracked battery may still work fine but should be replaced never the less due to safety reasons. 

Visible battery fluid leaks

Battery fluid should not leak off the battery. If it does, the battery should be replaced.

Discoloration (applies to filler cap lead-acid batteries)

If the color of the electrolyte fluid inside one or more of the cells has turned brown or dark, your battery is most likely bad. It does not matter if the other cells look healthy; if one cell is dark, the entire battery is rendered useless. 

Check the fluid level (applies to filler cap lead-acid batteries only)

Inside a conventional lead battery, there is electrolyte fluid that should reach up to a level where it fully covers the top of the lead plates or within a specified max/min level found in each cell. 

Carefully remove the filler caps and inspect using a flashlight. If electrolyte levels are low, top of with distilled water until you reach the correct level. Never try charging a dry battery as it may cause it to burn up.

If the battery has been sitting dry or with a low electrolyte level for too long, chances are it has sulfated beyond repair. 

Step 3: Charge the battery to see how well it holds a charge (open circuit voltage reading)

By fully charging a battery and then measuring its open-circuit voltage, you can tell quite a few things about its overall health. 

1. Charge the battery

If you are not sure how to properly charge your type of battery, I advise you to follow the steps in this guide.

2. Remove any surface charge the battery may have

After charging the battery to a full charge, and with the charger disconnected, allow the battery to “rest” for a minimum of 12 hours. 

This is necessary for the battery voltage to stabilize after the charging process, or you may get a false reading. Often there is a surface charge still present some time after disconnecting the charger. 

If you don’t have time to wait as long as 12 hours, you could also turn the lights (high beams) on for two minuts to remove the surface charge.

3. Measure the battery’s open-circuit voltage 

Use a multimeter or volt-meter to read the battery’s voltage under no load.

  • Disconnect the battery terminals to make sure nothing is drawing power from the battery. Always remove the black (-) cable first, then remove the red (+) cable.
  • Set the multimeter to “DC voltage 20” if you have a manual multimeter, or to “V” if you’re using a auto-ranging multimeter.
Multimeter settings for an open circuit voltage reading. Auto-ranging meter on the left, manual meter on the right.
  • Place the red lead on the positive (+) battery terminal, and the black lead on the negative (-) battery terminal.
test battery open circuit voltage
  • Use the table below to analyze your findings (applies to 12V batteries):
Open-circuit voltage readingWhat it tells you
0VTHe battery is not able to hold a charge. The battery likely has an internal short circuit and needs replacing.
Less than 10,5VOne or more dead cells.
Less than 11,8VThe battery is heavily sulfated beyond repair, and is not able to hold a suficcient charge.
Between 11,8V and 12,4V
(12,4V equals about 75% state of charge)
The battery is sulfated to a level where it may no longer be fully recoverable.
12.4V or moreThe battery his able to hold a suficcient charge. You can expect a high level of recovery by performing a desulfation charge.
Battery health in reference to it’s open voltage reading.

Step 4: Load test the battery to make sure it can provide enough amps (three different methods)

An open circuit voltage reading, as described above, is helpful but does not always paint the full picture. The battery may still be bad even if you get a reading of 12.4V or higher.

Sometimes, you will find that the voltage drops fast as soon as you draw power from the battery. If so, the battery is likely bad and needs to be replaced.

To test if the battery can drive a load, you can perform a so-called load test. The goal of this test is to make sure that the battery voltage does not drop too low when drawing a high load. 

A healthy ATV or UTV battery rated at around 200-400CCA should be able to maintain a voltage of 9,6V or more even under load (at 70°F (21.1°C)). A 400CCA battery should not drop below 10V.

Method 1 (Good): Multimeter load test

You will need a multimeter. Preferably one that has a max/min function. If you use a multimeter without a max min, you may get a false reading, as the display refresh rate cannot keep up to show the actual minimum voltage reading.

  1. Begin the test with a fully charged and rested battery; see steps 1 and 2 above. The open-circuit voltage reading should be 12.4V or more.
  2. Set the multimeter to DC voltage. 
  3. Connect the leads:
    1. The red lead goes to the positive battery terminal
    2. The black lead goes to ground
  4. Push the min/max button to start recording the voltage, or have someone observe the voltage reading.
  5. Activate the starter. The starter draws a high current from the battery in a short amount of time. It’s OK if the ATV starts.
  6. Turn off the engine and have a look at your readings. 
    1. A perfectly healthy ATV battery should not drop below the range of 9.6V to 10.5V (depending on battery CCA-rating and battery temperature at the time of testing).
    2. If your minimum reading is below 9.6 volts, your battery is likely bad. It does no longer hold sufficient capacity.
battery load test with multimeter
This battery is still able to start ATV, but the load test is telling me that it is getting close to the end of it’s service-life. The air temperature was around 32°F (0°C) when I did this test. Ths battery would likely get a higher reading if the test had been done in warmer weather.

Method 2 (Better): Consumer-grade load tester

A variety of consumer-grade batty testing tools are available in the $20 to 50 price range, where the two major types are digital and analog testing tools. Each tool has a specific user manual that needs to be followed, but I will outline how they work on a general level below.

Regardless of which tool you use, these guidelines apply:

  • Begin with a fully charged battery for more accurate results. You may get a good CCA rating in a halfway discharged battery, or you can get a bad CCA rating in a fully charged battery. So make sure the battery is fully charged to leave its state of charge out of the equation.
  • Disconnect the battery connectors and connect the testing tool directly to the terminals. This ensures that you get a solid connection, which leaves less room for a possible voltage drop.
  • It is safer to remove the battery before testing. In the unlikely event, something should go wrong during the testing; it is better to remove the battery from the ATV or UTV before running the test. A damaged battery may, in some cases, catch on fire or explode. 

Test with a conventional analog load tester

An analog testing tool uses a built-in resistance element/heat coil to simulate a high load. The tool measures the voltage drop under load, indicating if the battery is good, weak, or bad, relative to its CCA-rating*.

* CCA is the amount of current the battery can put out at -18°C (0°F) for 30 seconds while maintaining a cut-off voltage of at least 7,2V. You should find the battery’s CCA rating on the battery label. Each battery comes with a specific CCA rating. The actual CCA capacity decreases as the battery gets older or damaged.

  • Green (good): The battery capacity is OK.
  • Yellow (weak) or red (bad): The battery capacity is not ok. As long as you know the battery is fully charged, it is likely bad and needs to be replaced.

If the voltage recovers to its full potentil an only a couple of seconds after releasing the load switch, you know that the battery is bad. However, if the voltage recovers slow, yor battery is likely just run down and needs a proper charge.

atv battery load tester
The scale on a typical analof battery load tester.

Please refer yor the user manual of your testing tool for test directions specific to your tool.

Test with a digital battery load tester

Digital consumer-grade battery analyzers are inexpensive, compatible with most battery types, and can offer a range of test features such as:

  • Open circuit-voltage reading
  • Internal resistance reading
  • Actual CCA (Cold Cranking Amps) reading
  • AH test mode
  • Battery capacity reading, in %
  • Estimated battery life remaining, in %

To load test the battery you need to set the tool to its CCA-mode. You will need to insert the battery’s CCA rating before you begin the test. You should find the rating stamped on the battery casing, or by looking up the battery model number online.

Head over to this post to learn more about what ATV battery numbers mean.

The test will indicate how many CCA the battery is capable of.

test cca battery
This AGM ATV battery gets a CCA reading well over it’s rated capacity of 320CCA, and should be in good health.

Based on the measured CCA, the test tool may also provide you with a useful capacity reading or state-of-health reading in %:

State Of Health (SOH) in %Battery status
0% to 40%The battery is damaged or too old for normal operation and should be replaced.
40% to 60%The battery is getting old or getting weak. Consider replacing it.
60% to 80%The battery is in normal working order.
80% to 100%The battery is in good to excellent working order.

Measuring the battery’s internal resistance

A digital test tool may also be able to test the battery’s internal resistance. Resistance is measured in milliohms (mΩ) and tells you how much restriction the electrons encounter as they travel through the internals of the battery. A lower value indicates less restriction.

This AGM ATV battery has an internal resistance of 6.04 milliohms (mΩ).

The internal resistance of a modern ATV battery stays relatively flat throughout its service life and then increases as the battery starts to go bad. A high resistance reading indicates that the battery is getting close to the end of its life-span.

The internal resistance can vary as much as 5-10% from one batch of batteries to another. For the most accurate results, you need to measure the resistance of your specific battery when it is brand new as a reference for later testing.

A few years down the line, when you teat again and get a significantly higher reading, you know that the battery doesn’t have much time left.

Method 3 (Best): Ask a battery supplier to run a professional load test

Both Method 1 and 2 give you a relatively good indication of your battery’s health, but the accuracy of consumer-grade test tools are not always the best. 

To get the most reliable results, you should have it tested with a professional load testing tool. A proper load test should draw a load that is half of the batteries rated cold-cranking amps for 10 seconds. 

Most Battery suppliers have one and usually don’t charge to do a test. Disconnect the battery and bring it fully charged to be tested. 

What is battery sulfation, and how does it affect battery health?

Several of the tests in this post are designed to indicate your battery’s level of sulfation. But what is sulfation, and why does it matter when testing an ATV or UTV battery? 

Over-sulfation is the most common cause of premature battery failure. An undamaged battery with low levels of sulfation is healthy, while it gradually loses its capacity as levels of sulfation increase.

Therefore it can be helpful to have a general idea of what sulfation is and what it does to your battery:

  • All lead-acid batteries sulfate. This applies to both sealed and filler cap flooded (wet) lead-acid batteries as well as modern AGM batteries. 
  • Sulfation is the natural build-up of lead sulfate crystals on the lead plates inside the battery. 
  • Sulfation happens as a result of the chemical process that occurs between the electrolyte and lead plates as the battery discharges.
  • Re-charging the battery reverses the natural sulfation process, where most of the crystals turn back into the electrolyte. 
  • Since not all of the crystals go back to an electrolyte, the battery develops a small amount of sulfation build-up each time the battery is charged and discharged.
  • Overcharging, undercharging, or leaving the battery discharged for some time will cause rapid sulfation. Just a few days at a discharged state can be enough to cause permanent damage.
  • Low electrolyte levels where the lead plates are exposed to oxygen causes rapid sulfation build-up. 
  • Sulfation negatively affects the battery in several ways:
    • It reduces the battery’s ability to provide cranking power.
    • The battery will require more time to charge.
    • Increases heat build-up from the charge/discharge process, possibly causing the battery to “boil out.”
    • Reduces the battery’s ability to reach a full charge (lowers the available amp hours between each charge).
    • Significantly shortens the battery’s service life.
    • A sulfated battery self-discharge is faster than usual.
  • A desulfation charger may help to reverse the sulfation process, but only to some extent. When the level of sulfation has reached a certain level, the battery cannot be restored and needs replacing.
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I'm an ATV and offroad-enthusiast, an engineer, a farmer, and an avid home-mechanic. I'm also the owner and editor of BoostATV.com. If you have any questions or suggestions regarding this article, please feel free to contact me.