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Why Do Jeep Wranglers Have Two Batteries? Know in Details

Have you ever wondered why the Jeep Wrangler comes with two batteries? If so, cheers! I, too, had the same amazement initially. In this article, I will explain in detail: why do jeep wranglers have two batteries?

The two batteries installed in the Jeep Wrangler will provide a longer service backup. It helps to enhance the performance of electrical components, and thus, the load does not shift to single battery. Two deep-cycle batteries in Jeep allow to run all the accessories longer without being recharged.

Off-road enthusiasts highly demand Jeep Wranglers because of their specs and features. This vehicle holds all the necessary specs for an excellent off-roading adventure. If we talk about the battery, many jeeps are equipped with a single battery and perform their functions with it. It is said that the jeep Wrangler has two batteries, and it enables it to stand among others in the market.

Why Does My Jeep wrangler Have Two Batteries?

Every vehicle is equipped with batteries with their engines, which start the car and operate the electrical components inside the car, such as lights, horns, DVD player, and similar. Whereas in jeeps, the system is a little different.

The jeeps have two batteries present inside their hood. The two batteries are connected to the car by all means but serve differently.

Why Do Jeep Wranglers Have Two Batteries

The system designates one battery for cranking, and the other battery for the accessories

One of the two batteries is the primary battery. This battery serves the purpose of cranking the truck. When the driver rotates the key in the vehicle's ignition switch, it produces a cranking sound. It is called to crank the truck. This cranking sound indicates that the starter is doing their job great. So the primary battery of the jeep is placed for starting the vehicle.
The second battery is known as the secondary one. It is the auxiliary battery and is used to provide power to the electrical components present in the car. The power is produced equally to both the batteries to get charged equally as the engine starts running.

We have created the infographic below that covers the reasons on why jeep wrangler has 2 batteries. (You are welcome to use and share but please credit us if you do so.)

Why Do Jeep Wranglers Have Two Batteries

Working On the Dual Battery System:

The dual batteries are designed to work the cranking system and accessories, respectively. According to their charging setup, the smart isolator with the jeep links both batteries.

Firstly, the cranking battery is charged up, and the accessory battery charges. The two batteries and their association provide an extended time to run the vehicle even when the engine turns off.

The smart isolator can disconnect the batteries when the batteries drain out. It prevents the cranking battery from draining as accessories connect with it.

But still, there are chances that the cranking battery might drain out as the headlights, radio, and outlets are connected. You can use the built-in boost button if the engine is not starting and can temporarily link your batteries together. It will help you to start the engine using the second battery. 

Why do Jeeps Have an Auxiliary Battery?

The Aux battery keeps accessories and computers alive when the ESS stops the engine. Aux battery cannot alone fulfill the current demands to start the motor. It is helpful to keep the system in a running situation when the alternator produces nothing. 

How do Two Batteries in Jeep Wrangler Function Together?

The circuit connection of both the batteries has to be made as a parallel circuit. One of those batteries is known as the primary one, responsible for the function of cranking the vehicle.

It means that this would make the vehicle start and move. The secondary one is the auxiliary battery, which powers the accessories and add-ons in your vehicle. As the driver turns on the vehicle, electric current from the alternator flows to the dual batteries.

Benefits of Dual Batteries in Jeeps:

The dual batteries in a jeep are helpful and effective in vehicles. There are various benefits of dual batteries, among which some of them are as follows:

Long winchesWinch is a machine that is helpful to tow the vehicle. People love to create modifications in their vehicle and install winching machines in their vehicle.

Winching machine requires extra power for starting although that power is just for few seconds.

There are chances that battery might drain out earlier than before due to winching machine even if the engine is turned on. So, dual batteries are helpful in such case.
Emergency backupWith the advancement of technology, we believe that the branded and new products launched in market will work out longer for us.

But still it is seen that there is no specific time limit for the working duration of technological items. If there is any technical fault in a device or item, no prior notice is given.

In case of batteries, there are chances that they might run out before their duration so it is better to have dual batteries as they can act as an emergency backup provider. 
Extra comfortDual batteries enable to use the accessories like stereo system, radio and smartphone chargers.

All these accessories require electricity to run and can lead the single battery to drain out earlier.

With a dual battery, you can enjoy all these add-ons with your vehicle without the fear of running out of battery.
Make-shift generatorYou can convert your auxiliary battery to a make-shift generator using a dual battery system. You can power your laptop or invertor with it.

Are Two Batteries Better Than One in Jeep?

A 12-volt battery consists of two six-volt cells in a series combination. Their size often leads to the problem of installation, so one form is better in such cases. People consider a 12-volt battery as a single one, but it holds two batteries determined from an electrical point of view.

Why Does My Jeep Shake At 40 MPH? All You Need to Know

The Best Battery Recommendations for Jeep Wrangler:

Here we will discuss some best battery recommendations for you that you can install in your vehicle:

1. 7ah Rechargeable Sealed Lead Acid Battery:

Why Do Jeep Wranglers Have Two Batteries
  • This sealed lead acid battery is considered the highly reviewed and best battery. It is a genuine expert-powered battery of 12 volts and includes a sealed lead acid battery that works for more than 20 hours.
  • This battery type is maintenance-free, and its case is made up of non-conductive ABS plastic.
  • This battery holds strong resistance to vibrations, heat, and shock.
  • It is easy to install and does not require maintenance. The acid present in the battery is absorbed by the plates and is immobilized by a fine fiberglass mat.

2. 12-Volt Rechargeable Battery:

Why Do Jeep Wranglers Have Two Batteries
  • It is a kind of replacement battery used to power the wheels of vehicles. It is a 12-volts battery that is helpful to power any vehicle and requires a 12-volts ampere or battery for smooth operation.
  • This battery does not include a battery charger, and it is advisable to use the one you use for charging the battery to power your wheels.
  • It is advisable to fully charge the battery before storing it to prevent premature battery failure.

3. Yellow-Top Dual Purpose Battery:

Why Do Jeep Wranglers Have Two Batteries
  • This dual-purpose battery has the capacity of 55-ampere hours and is more resistant to shocks and vibrations. It is a highly durable item and holds the case material made up of polypropylene.
  • This dual-purpose battery has a reserve capacity of 120 minutes which helps it perform constantly.
  • It holds an optimal starting power and can operate even in bad weather.

Type of Batteries for Appropriate Use:

It is recommended to go for the batteries from group 34. Group 34 is the size of the battery and is one of the most important things to learn. This group and size are capable enough to hold all the Jeep accessories and can be fitted under the hood.

Factory batteries lack the power to boost their impressive capacity and average performance. Two regular batteries will work out excellently if you have no wish to use winches or lights. 

But if you want to have an excellent setup and do not want to face the issue of power, then deep-cycle units are the best and reasonably priced options. Go for the identical batteries while purchasing the dual-kit system made by the same model and brand. 

The Isolator and Its Importance:

The isolator is a key component of the dual-battery system. It is helpful to handle the charging process and prevents the primary battery from drying out. An isolator is equipped with extra accessories, including:

  • A battery cable
  • An earth cable
  • Battery terminals of negative and positive brass
  • Lug connectors
  • Cable ties
  • Detailed instructions

Although isolators are easy to install, it is still recommended to get them fixed by a pro person who is an expert in wiring. If you are capable enough to do so, it is best to go for manual wiring to save money.

Before purchasing an isolator, look for IP65 certification on it. It ensures that the isolator was thoroughly tested and is safe to use in any harsh environmental conditions like harsh winters or humid summers. Try to fix it under the hood or your seat and protect the battery kit. 

Things to Consider for Isolated Dual Batteries in Jeep Wrangler:

  • It is recommended to use two identical batteries for even charging from the alternator. It is done so because the two batteries are connected in parallel as the engine runs.
  • It is recommended to buy a good solenoid so that it may last longer.
  • It is advisable to look at your accessories for the longevity of your battery. It is not a good idea to keep the big camp light on the whole night, as it will drain the battery.

Also Read:

Why Does My Jeep Wrangler Keep Beeping? All You Need to Know
How Long Do Jeep Wranglers Last?
Can You Lower a Jeep Wrangler? All You Need to Know
The Top 10 Jeeps for Off-Roading
Can All Jeeps Go Off-Road? All You Need to Know

Frequently Asked Questions (FAQs):

Why do Jeep Wranglers possess two batteries?

There are two batteries in a Jeep Wrangler, and one designates for cranking. The other battery designates for the accessories. It is helpful if the cranking battery gets fully charged, the isolator links both batteries, and the accessory battery is charged up.

Why is there an auxiliary battery in the Jeep?

The auxiliary battery in the Jeep keeps the accessories and computer in an alive state. It works when the ESS stops the engine, and the battery is not sufficient to provide the cranking current to start the motor.

Are there two batteries in a Jeep Wrangler?

The dual battery in Jeep Wrangler is the best option, and people demand such in their vehicle. But most of them are not aware that the Jeep Wrangler is equipped with two batteries.

Are the batteries necessary in the Jeep?

It is good to have two batteries in the Jeep to handle all the accessories. The factory’s batteries in a jeep cannot boost the impressive capacity. A set of two regular batteries is enough if you will not use the winches or lights.

Are the two batteries better or the one?

There is no difference between the batteries, and both hold the same volts. Sometimes there is an issue with installation, so one battery is better in such cases.

What is the average cost of the jeep batteries?

If you want a Jeep battery replacement, the average price falls between $220-and $230. In this cost, $40-$50 is for the labor, and $180 is spent on purchasing the parts.

What happens when you connect both the batteries in series?

When you connect both the batteries in series, the flow of electrons is the same throughout the circuit.

Does the battery holders place in series or parallel circuits?

There are different ways to check the circuit of the batteries. If you notice a wire connected through a positive and negative terminal, the battery is connected in a series connection.

Is series connection good for connecting batteries or parallel?

The parallel combination increases the capacity while the series increases the voltage. 

How long does an average jeep battery last?

An average jeep battery lasts for about 3-5 years. It depends on the type of battery, the habit of driving, and weather conditions. 

What happens when the batteries are reversed?

The reversal of batteries can lead to damage to the unit. It is advisable not to play with reversing the polarity of batteries. It will drain and ruin the batteries, and there is a potential risk of damage.

Why is parallel connection good for batteries?

The parallel connection increases the total current carrying capacity. It decreases the total resistance and increases the overall amp-hour capacity. All the batteries have the same voltage rating.

Which thing should be ensured when two batteries are connected parallelly?

The person should make sure that the batteries have the same EMF. It is necessary to avoid any circulating current between the batteries.

Is there a need for special batteries for Jeep Wrangler?

There is no need for special types of batteries for a Jeep Wrangler. There is a single battery in non-hybrid jeeps used to store electricity.

amer hamoud

Tuesday 20th of September 2022

my dash board is completely off all the gauges and speedometer are not working but the jeep starts and drive well. what is the cause for this.


Tuesday 20th of September 2022

This could be due to a damaged dash cable or a defective instrument cluster, or the vehicle's fuse.