How to Build a Battery Box: Step-by-Step Guide (With Images)

Knowing how to build a battery box can help you keep the electrical components, including your batteries, safe inside any moving RV. While some RV enthusiasts think that a battery box is “just an accessory”, it does more than just keep the inside of your trailer organized. In this blog post, you will not only learn which are the different types of batteries in RVs and trailers but also how to build one completely by yourself. Let's get started!

Types of Batteries in RVs and Trailers

battery box

To understand how to build a battery box for your RV, trailer, van, or camper, you must familiarize the different kinds of batteries. RVs typically use two batteries: starting, lighting, ignition (SLI) batteries, and deep-cycle batteries.

  • SLI Batteries

SLI or "starting" batteries are 12-volt batteries that supply a sudden burst of power to start the engine. Once the engine is on, the alternator recharges the starting battery.

  • Deep-Cycle Batteries

On the other hand, deep-cycle batteries are essential for “deep cycle” functions such as powering the lights, water heater, etc. even when the RV is turned off. Deep-cycle batteries are designed for prolonged use. They offer a steady stream of current to power electronics and appliances. Additionally, deep-cycle batteries won’t get damaged even after constant discharging and recharging.

  • Marine Battery

Some RV owners prefer to purchase a marine battery, which is a combination of a starting battery and a deep-cycle battery. While marine batteries consume less space, they typically don’t last very long.

Why You Need a Battery Box?

battery box RV

A battery box is a necessary accessory for any RV enthusiast. If you’re planning on going on a long-distance road trip with your camper, it’s a good idea to secure your main power source inside a battery box. Before you learn how to build a battery box, we have compiled several benefits of having one.

1. User Safety

Protect yourself and your passengers from hazardous chemicals. Batteries can produce chemicals that are harmful to people, animals, and the environment. Keeping the battery inside a battery box reduces the chances of leaks and spillage of toxic substances. Learn more about this here.

2. Protection from the Elements

Just like any piece of equipment, batteries are at risk of exposure to the elements such as dust, dirt, and water. Debris can accumulate within the batteries, resulting in short circuits and permanent damage. Protect your battery from the elements by storing it inside a well-built battery box.

3. Longer Battery Life

A well-maintained RV battery should last around six years. However, most RV owners replace their batteries each year due to poor maintenance. The life expectancy of your battery depends on how well you take care of it. Keeping your battery inside a battery box ensures that your battery is protected throughout your journey. Speaking of this, make sure to check out our other blog post regarding the RV battery box disconnect switch here.

Types of Battery Boxes for RVs and Trailers

Types of Battery Boxes for RVs, Trailers, etc.

There is no one-size-fits-all kind of battery box, as batteries literally vary in size. Generally, there are three types of premade battery boxes: plain, vented and modified. When deciding how to build a battery box, you can take inspiration from these types to build your do-it-yourself (DIY) battery box.

1. Plain Battery Box

The most ordinary battery box is made of plastic or metal. Usually, this plain black battery box comes free whenever you purchase a battery, but you can always pick one up at an affordable price. While plain battery boxes are lightweight, they offer only minimal protection.

2. Vented Battery Box

A popular choice is the vented battery box, which provides its ventilation system for air and fumes. Most vented battery boxes only have vents, while others feature a hose to release the fumes outside.

3. Modified Battery Box

A modified battery box is a premade battery box that a user-customizes to include features such as locks, vents, and so on. It’s typical for users to modify their battery boxes to suit their specific needs.

How to Build a Battery Box By Yourself

Your design may differ from what other RV owners have built since it largely depends on your specific requirements, such as where you intend to place the battery box, the size of your batteries, the number of batteries, and so on. For this guide, we’ll teach you how to build a battery box for two 155AH deep-cycle batteries that measure approximately 13 x 6 x 11 inches each.

Step-by-Step Guide on How to Build a Battery Box

Step 1.

Cut the plywood pieces into your desired dimensions. We recommend keeping it spacious to leave room for the battery terminals.

Step 2.

Connect the cut-out pieces of the box with pocket holes.

Step 3.

Drill through the pocket holes and then screw the pieces together with 1-inch pocket hole screws.

Step 4.

With the furring strips, create a spacer at the bottom of the box. This helps secure your battery inside the box so you don’t have to worry about driving through rugged roads.

Step 5.

Place the batteries in the box to see how they fit.

Step 6.

Drill holes in the front, top, sides, and back of the battery box. The holes provide ventilation but also function as holes for wiring.

Step 7.

Install D-ring anchors inside the box, with one in the front and one in the back. These anchors let you strap your batteries in place.

Step 8.

Install a lid by screwing a piece of plywood to the top of the battery box. You can also angle the lid by connecting two pieces of plywood with a piano hinge.

Step 9.

Mount the batteries inside the RV. Where you position it is up to you, but we recommend screwing it down if your RV has laminate or wood flooring. This ensures that your DIY battery box won’t slide around.

Step 10.

Secure the batteries with tie-down straps just as you would with a suitcase that’s about to burst. If you want to see how exactly looks like more visually, check out this video:

If this seems like too much work for you, then check out this one that is available on Amazon:

Final Thoughts

And that’s how to build a battery box! You can use other materials like aluminum or plexiglass and add other useful features like a vent or hose. Often, making your own battery box results in a sturdier item compared to the readily available ones. In addition, it is also not crucial to have one, however, knowing how to build a battery box can is a handy skill for any RV owner.

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