Upgrading and accessorizing your UTV is one of the best parts of owning one. Some mods – like increasing the carrying capacity – open the door to limitless customization options. And some are more subtle than others… like adding a second battery.

Two Riders with a RZR on a Mountain Trail

Why You Might Want to Add Another Battery in Your UTV

It all comes down to the electrical needs of your machine. Most UTVs are designed to accommodate basic use of the stock features on a single battery. However, if adding a new speaker system or winch sounds appealing, you might want to look into adding an extra battery.

What Happens with a Second Battery

Ideally, the electrical system will produce more energy while the UTV is running than it actually requires. Excess energy is transferred back to the battery using the stator. But in a situation where your power requirements are greater than your output, a second battery can supply the deficit. This won’t actually change your UTV’s ability to generate power while it’s running, but it will provide a greater supply of spare power, decreasing the likelihood of your primary battery going dead while you’re blaring music during a lunch break or keeping that heater blazing when the motor is off.

First, you’ll need to determine where to place the second battery. In many situations, you can fit it underneath the driver’s seat. Then you need to wire the batteries together, ensuring that they are in a parallel situation. What does this mean? The positive terminals must be connected to each other, and the negative terminals must be connected to each other.

Picture of a Simple Diagram Demonstrating Two Batteries in a Parallel Setup

Do not connect a positive terminal to a negative terminal, creating a series. You may have seen this in other situations involving batteries, but this is not the appropriate setup in this case. Putting two batteries together in a parallel arrangement will increase their total amp hours. Putting two batteries together in serial arrangement will increase their voltage – which you don’t want.

The Deal with Deep Cycle Batteries

For this sort of application, there are two sorts of batteries that you’re dealing with: starter batteries and deep cycle batteries.

Starter batteries are installed in nearly every automotive application and are used to actually start the vehicle, hence the name. They are designed to deliver a short – but high-powered – burst of energy that is required to start the engine. Cranking amps refer to the amount of energy the battery can supply during this short time period. This is most likely the type of battery that your UTV already has.

Deep cycle batteries are used in a variety of applications. They’re sometimes called marine, RV or golf cart batteries because they are used in all of these types of vehicles. Deep cycle batteries are designed to deliver a prolonged – but weaker – current of energy used to run different types of equipment.

In actuality, both batteries can provide either application. A starter battery can run electrical equipment. A deep cycle battery can start an engine. However, because they are designed to excel in a specific use, they won’t be as effective. For this reason, a starter battery will have fewer charging cycles before dying than an equivalent deep cycle batter when running electrical accessories – and vice versa when starting an engine.

Some batteries are designed as a compromise and work effectively as both a starting battery and a deep cycle battery. This is not a “super battery” by any means, as it is not as effective in either area as more specialized batteries. Instead, it’s better to pair a starting battery together with a deep cycle battery.

Installing Isolators

You can place starting and deep cycle batteries in a parallel setup. To gain full advantage of each, some riders have them operate separately, keeping the UTV’s starter motor and stock equipment connected to the starting battery and the deep cycle battery connected to peripheral accessories.

However, many riders install an isolator or an automatic charging relay when using starting and deep cycle batteries together. What do these do? They isolate or separate the two batteries while still allowing them both to operate as needed.

An isolator or automatic charging relay will prevent your auxiliary electrical components from draining your starting battery, ensuring that you don’t find yourself stranded on the trail.

A Word of Caution

It’s best to use two batteries of the same type. Don’t mix lead acid batteries with gel batteries or similar combinations.

UTV Riding Away on the Redrock

Conclusion

Dual battery setup is not for everyone who owns a UTV. However, more and more riders are noticing the benefits of having an additional battery.

If you’re ready to add a second battery, you can find a lot of the items you need at a local auto parts store. If you’re a RZR owner, we stock a simple auxiliary battery kit that has everything you need and is manufactured by Polaris specifically for this application. And don’t forget to check out our UTV battery section if you want to pick up an extra battery.

Technician Disclaimer