Why Do Jeeps Have Two Batteries?

Though we'll not go into the high-tech details, there're still some basic things to understand concerning your dual jeep batteries. I know you wouldn't like to be stranded anywhere due to battery drainage in your jeep.

No matter how strong a battery is, it will run down with time. Also, a typical lead-acid battery can’t drive your vehicle and still support all the accessories and add-ons. Some of those accessories include bright LED lights, a radio, an air compressor, a winch, a smartphone charger, etc.

You must understand that having more batteries for your jeep gives you a longer service time from them.

A dual battery system is made to have the capacity of keeping your jeep and its accessories operating perfectly well in every condition. Thus, dual batteries are important for more capacity output before recharging when they run out.

Looking for the best jeep battery? Here's our top 3 recommendations!

How Two batteries Function?

The connection of the two batteries is made to be in parallel. One of the batteries, which is the primary battery, is responsible for cranking. This makes the vehicle start and move. The second battery is the auxiliary battery, which powers the accessories and add-on in your vehicle.

The link in the two batteries is connected to an isolator of the vehicle. The isolator mainly operates by preventing the primary battery from discharging when the vehicle is not functioning. There may or may not be a manual switch for the isolator to cancel this operation.

As you on your vehicle, electric current from the alternator flows to the dual batteries. The current will be able to charge the two batteries as the isolator permits the passage of the current.

This implies that it’s the isolator that controls the charging processes of the dual battery. The primary battery is first charged, after which the isolator links in the auxiliary battery for charging.

As you start your vehicle and drive, the two batteries share the load evenly. This makes it possible for you to have longer runtime, unlike what is obtainable for a single battery system.

However, as you consume some of the energy and the voltage of the batteries begin to drop (say 12.8 volts), the isolator will react immediately. It will disconnect the link between the two batteries.

Through this disconnection, it shields the primary battery from complete drainage, which can result in a dead battery. So, the isolator is the saver of the primary battery.

Furthermore, the vehicle wouldn’t keep you stuck on the road. This implies that even with the dual battery system in your vehicle, there’s still a need for a good isolator to control the operations of the batteries.

The powering of headlights, smartphone charger, radio, and other add-ons are bu the auxiliary battery. In cases of sudden drainage of the primary battery, the auxiliary battery can step in and start up the vehicle.

This is normally referred to as ‘jump-starting.’ This will then enable the primary battery to get charged again as the electric current flow. When you park the vehicle, the isolator disconnects the primary battery so it won’t discharge.

This saves you the trouble of having a dead starter battery. Thus, the auxiliary battery provides the power for any accessories you decide to use, such as the fridge or radio.

Benefits of two batteries in jeeps?

The dual battery system in jeeps makes them perform optimally.  Below of some benefits of a dual battery system:

It enables longer winching: Lots of people install their winching machines in their jeeps. Winching consumes much power from a battery. If starting up a car takes a bit of the power for just a few seconds, winching swigs deeply. Remember that winching can run for some minutes.

This means the possibility of battery drainage within a very short period, even when the engine is on. There’s no way the alternator can charge up your single battery so fast during winching.

Hence, the need for two batteries. A dual battery system shares the effects of winching between the two batteries and prevents complete battery drainage during winching.

It provides emergency backup: We all know how tech engines work. They will never give you any pre-notice before disappointing or developing any fault. Besides, batteries do die with time.

It can happen when you have an important place to go. Worst-case scenario, it can happen in the middle of nowhere with very bad weather.

It can be frustrating to be in such situations. So, a second battery comes as a backup to keep you going without any stress. You just have to make a switch from the primary battery to the auxiliary one, and you are good to go.

It provides extra comfort: Having a dual battery system gives you more comfort and enablement to use some accessories and add-on that consume power. You can enjoy the use of a fridge, a stereo system, a radio, a smartphone charger, and others. These accessories can use quite a lot of electricity.

With these extra, a single battery can easily be drained. By using two batteries, you don’t bother about the effect on your battery. This is because while the primary battery will power the vehicle, the auxiliary battery takes care of all the extra comfort.

This allows you even to camp out and still enjoy these accessories. You can keep some food like meat, vegetables, and fruits all fresh while on such camping.

It can be your make-shift generator: With a dual battery system, the auxiliary battery can become your make-shift generator. You can connect it to power an inverter for your laptop or provide lights in a tent or cabin.

Also, you can use it to power your onboard showers. Even with all these usages, you’re sure that your jeep will not become redundant due to a dead battery.


It’s never been sweeter and easier to run your jeep with two batteries. They boost your confidence of not getting stranded due to a dead battery.

Furthermore, your dream of having extra comfort in your ride has become a reality. You can enjoy adding some accessories to your vehicle without worries.

Click Here to Leave a Comment Below 0 comments

Leave a Reply: