There are few things more annoying than getting ready for an exciting ATV trail ride, only to find the battery completely dead. You turn the key, but nothing happens, not even a click or a flicker of light.

Luckily, you may be able to restore your dead battery to complete working order, as long as it didn’t sit without a charge for too long.

Not All Dead Batteries Can Be Charged

A battery that has been sitting dead for quite some time has likely gone bad due to excessive internal sulfation and cannot be salvaged. 

When a battery drops below 11.5 volts, an internal chemical process known as sulfation begins and continues until the battery loses all of its capacity or eventually shorts out. This process happens gradually but advances relatively fast when the battery sits without a charge. 

However, a battery that’s merely drained overnight by leaving the lights on by mistake or from a short somewhere in the ATVs wiring can usually be revived back to complete working order. It’s crucial that you discover the issue before too much time has passed and that you charge the battery as soon as possible.

Related: 10 Reasons Why Your ATV Battery Keeps Draining (Going Dead)

But what if your smart charger won’t charge the dead battery?

As a safety precaution, modern smart chargers (or automatic chargers) are designed not to charge defective batteries. While the general idea behind such a feature is good and has likely prevented several charging accidents, it doesn’t always work out as intended.

The problem arises when your smart charger, due to a low voltage reading, mistakenly believes that your battery is faulty and refuses to initiate the charging process. In that case, we need to be a bit creative.

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

How to Charge a Dead ATV Battery

If your smart charger refuses to initiate the charging process on your dead or drained battery, you can use a healthy and fully charged battery to boost the charging process.

The method involves using the healthy battery to pre-charge the dead battery until it’s above the minimum voltage level of the charger. 

Caution: Only attempt this method if you know for a fact that the battery is drained but otherwise in good condition. If the battery has been sitting without a charge for a more extended period, it is likely sulfated to an extent where it can no longer be reconditioned. 

Connecting a healthy battery to one that shorted out or otherwise damaged may cause damage to the healthy battery as well.

Charging batteries can be harmful if you are not careful. Always wear rubber gloves and proper eye protection, as well as perform the procedure in a well-ventilated area. 

Things you will need:

  • A 12V smart charger with a low-amp charging mode for motorcycle and power sport batteries. 
  • A healthy and fully charged 12V battery such as another ATV battery or a car battery.
  • A set of jumper cables.

1. Disconnect the Battery and Remove It From the ATV

Because you are dealing with a battery that may or may not be damaged, it is always a good idea to disconnect and remove the battery to charge it somewhere at a safe distance from the ATV. That way, if something unexpected were to happen, like a short, you don’t risk damaging your bike.

Here is a step-by-step guide on how to safely remove and install an ATV battery

2. Connect the Dead (drained) and the Healthy Battery

Place the two batteries next to each other in a well-ventilated area. Connect the two batteries in parallel using the jumper cables in the following pattern:

  • Connect the two negative battery terminals (marked with the symbol “-“) using the negative (black) jumper cable lead.
  • Connect the two positive battery terminals (marked with the symbol “+”) using the negative (red) jumper cable lead.
TIP: Insert bolts in the battery terminals for a proper connection.

The dead battery will now feed off the charge from the fully charged battery.

Caution: With the red lead connected to the battery, the other end of the lead is hot. Be careful not to touch the negative battery terminals, the negative (black) jumper cable leads, or anything grounded as it will cause a short. Shorting out a battery will likely cause permanent damage to the battery and can be very dangerous.

3. Leave the Batteries Connected for an Hour

Leave the two batteries connected for an hour or so to allow the dead battery to gain some charge. Do not let it sit too long tho, as this may drain the healthy battery below what is recommended. 

4. Disconnect the Jumper Cables

When disconnecting the jumper cables, do it in this order:

  1. Fully charged battery positive cable
  2. Low battery positive cable
  3. Low battery negative cable
  4. Fully charged battery negative cable.

Optional: After disconnecting the jumper cables, use a multimeter or voltmeter to read the voltage level of the dead battery. The meter should now read 11,5V or more. 

If you do not have a multimeter at hand or don’t know how to use one, you may safely move on to the next step. If the charger is still unable to initiate the charging process, the voltage level of the dead battery is likely still not high enough. 

In that case, reconnect the jumper cables and let them sit for one more hour. If that doesn’t help bring the voltage level up, the battery is likely bad and needs replacing. 

5. Connect the Battery Charger to the Dead Battery

Connect the battery charger to the dead battery like you usually would:

  • The negative (black) lead of the charger attaches to the positive (-) battery terminal.
  • The positive (red) lead of the charger attaches to the positive (+) battery terminal.

6. Initiate the Charging Process

Now that the battery and charger are set up, it’s time to plug the charger into a wall socket and initiate the charging process like usual. As a rule of thumb, you should use a charger with a charging output of no more than 1/10th of the batteries rated CCA. On an ATV battery, this is typically around 2 Amps. 

Check this post if you want to learn how to identify your battery’s CCA and other crucial metrics. If you need a more in-depth guide on how to charge a battery, please refer to this illustrated step-by-step guide.

7. Charge for up to 24 Hours

Hopefully, the charger will now initiate the charging process as normal. In that case, allow the battery to fully charge until the charger shuts off automatically or enters a maintenance mode. 

This process usually takes up to 24 hours with a battery that is completely drained. 

8. Install the Fully Charged Battery to the ATV

With a full charge, the battery is now ready to be installed on your ATV again. 

  • First: Connect the RED positive (+) cable to the positive battery terminal.
  • Second: install the BLACK negative (-) cable to the negative battery terminal.

9. Charge the Healthy Battery

Remember to charge the healthy donor battery after successfully charging the dead battery to a full charge. It has likely lost quite a bit of charge from being used to boost the dead battery. 

How to Charge a Dead Battery Using a Manual Charger

As an alternative to using a donor battery and a smart charger, you may use a manual charger to charge the battery overnight at a low-amp setting. 

It may need some time to get the charging process going, but you’ll get the best result by not going too hard on the amps. When it comes to charging batteries, slow and steady winch the race every time. 

If the lowest amp-setting did not raise the charge when left connected overnight, consider stepping up one notch in amp output. 

Caution: When charging ATV batteries, you should never exceed 3Amp charger output. Note that car chargers typically come with an output of 10A or more. Charging an ATV battery at this rate will overheat it and cause permanent damage.

What Is a Dead ATV Battery?

A battery is considered dead when it drains to a charge near zero. While a battery with a charge just under 11.5 volts does likely not have enough power to start a vehicle, it is still not completely dead. 

But when a battery sits for too long at a deficient charge (below 11.5V), it will soon become completely dead due to internal sulfation. 

How Does an ATV Battery Die?

There are many ways for an ATV battery to drain to a level where it is considered completely dead.

In some instances, you can restore the battery as long as you charge it before it sits too long with a low charge. Typical scenarios where an ATV battery drains and go dead:

  • When unintentionally leaving the lights on overnight.
  • From extensive winch usage, pulling more power than the ATVs built-in charging system can keep up with. 
  • From old age. An ATV battery typically lasts 3 to 5 years in real-world conditions. 
  • Low fluid levels in the battery. This only applies to serviceable batteries. Do not attempt to open a sealed battery. 
  • From a loose or corroded ground cable. 
  • From parasitic amp-draw: When an issue in the electric system causes a small current draw that may drain the battery completely given enough time. 
  • When the ATVs charging system is not working properly, typically bad stator or regulator.
  • From driving in extreme sub-zero temperatures.
Previous articleHow to Know if You Need a Winch on Your ATV or Not
Next articleWhat Is the Biggest ATV? (By Size, Hp, Torque, Weight)
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.