2008 Polaris Rzr 800 Battery Size - The Complete Fitment & Upgrade

There’s nothing worse than gearing up for a day on the trails, turning the key on your RZR, and hearing that dreaded… click. A dead battery can kill an adventure before it even starts. We’ve all been there, and it’s a frustration every off-roader wants to avoid.

You know you need a new battery, but the world of powersports batteries can be confusing. What fits? What do all those letters and numbers mean? Can you get something better than the original?

Don’t worry, we’ve got you covered. This is your definitive guide to the 2008 Polaris RZR 800 battery size. We’ll demystify the specs, show you how to choose the perfect replacement, explore powerful upgrade options, and give you the pro tips to make your new battery last for years. Let’s get your rig powered up and ready to ride.

What is the Factory 2008 Polaris RZR 800 Battery Size?

Let’s get straight to the point. The original equipment manufacturer (OEM) battery for a 2008 Polaris RZR 800 is a standard powersports battery size known as YTX14AH-BS.

This isn’t just a random string of characters; it tells you everything you need to know. Understanding this code is the first step in our comprehensive 2008 polaris rzr 800 battery size guide.

Decoding the Battery Lingo

Here’s a quick breakdown of what that “YTX14AH-BS” label means for you:

YTX: This designates it as a high-performance, sealed, maintenance-free battery manufactured by Yuasa, but the “YTX” prefix has become a general industry standard for this type of battery.
14: This is the power rating or performance indicator. A higher number generally means more power.
A: This can indicate a specific case size or terminal configuration within that power family.
H: This stands for “High Performance,” meaning it has a higher cranking capacity than a non-H version.
BS: This tells you the battery is shipped dry with its acid pack separate (“Bottle Supplied”), which you or the retailer must add to activate it. Most modern replacements, especially AGMs, now come factory-sealed and activated.

Standard Dimensions and Specs

While brands may vary slightly, a YTX14AH-BS battery will have these approximate dimensions:

Length: 5.31 inches (134mm)
Width: 3.50 inches (89mm)
Height: 6.56 inches (166mm)

The key takeaway is this: any battery with these dimensions and the positive terminal on the left side will physically fit in your RZR’s battery tray.

Why Getting the Right Battery Size is Mission-Critical

Choosing the correct battery isn’t just about making it fit in the tray. The proper 2008 polaris rzr 800 battery size impacts safety, performance, and the longevity of your machine’s electrical system. Ignoring this can lead to some serious trail-side headaches.

Here are the core benefits of 2008 polaris rzr 800 battery size precision.

Perfect Fitment and Vibration Resistance

Off-roading is a brutal environment. Your RZR is constantly shaking, bouncing, and vibrating. A battery that fits snugly in its tray and is secured by the hold-down bracket is essential.

A battery that’s too small will slide around, risking damage to the battery case and internal plates. A battery that’s too large simply won’t fit without sketchy modifications you should never do.

Optimal Power Delivery

The correct size ensures the battery terminals are in the right location. This allows your positive and negative cables to connect cleanly and securely without stretching or kinking.

A poor connection is a point of high resistance, which means less power gets to your starter and accessories, and it generates heat that can melt terminals and wiring.

Safety First: Preventing Short Circuits

This is the big one. A loose battery can shift and make contact with the metal frame or other components. If the positive terminal grounds out on the frame, you’re looking at a dangerous short circuit—a major fire hazard.

Using the exact size specified for your RZR ensures it stays put, keeping you and your machine safe.

How to Measure and Confirm Your 2008 Polaris RZR 800 Battery Size

Even though we know the standard size, it’s always smart to double-check before you buy. A previous owner might have installed something different. This section covers how to 2008 polaris rzr 800 battery size verification right in your own garage.

Tools You’ll Need

This is a simple job that requires basic tools:

Socket set or wrenches (usually 10mm for terminals and the hold-down)
Tape measure
Wire brush or battery terminal cleaner
Safety glasses and gloves

Step-by-Step Measurement Guide

Safety First: Always disconnect the negative (black) terminal first, then the positive (red) terminal. This prevents accidental sparks if your wrench touches the frame.
Locate the Battery: On most 2008 RZR 800s, the battery is located under the driver’s seat. You’ll need to remove the seat to access it.
Remove the Hold-Down: Unscrew the nuts or bolts securing the battery hold-down bracket and set it aside.
Lift Out the Old Battery: Carefully lift the battery out of the tray. Be aware, lead-acid batteries are surprisingly heavy.
Measure and Inspect: Use your tape measure to get the Length, Width, and Height of the old battery. Compare these to the standard dimensions listed earlier. Also, take a moment to confirm which side the positive terminal is on.

Pro Tip: While the battery is out, inspect the battery tray for dirt, debris, or corrosion. Clean it out thoroughly. A clean tray helps prevent premature battery failure.

Common Problems with 2008 Polaris RZR 800 Battery Size & Selection

At FatBoysOffroad, we see the same mistakes over and over. Avoiding these common problems with 2008 polaris rzr 800 battery size selection will save you time, money, and frustration.

The “It Almost Fits” Mistake

Don’t be tempted by a battery that’s “close enough.” A slightly taller battery might prevent the hold-down from securing properly. A slightly wider one might require you to force it in, which can crack the case. Stick to the exact OEM dimensions.

Ignoring Terminal Orientation

This is a classic blunder. You find a battery with the right dimensions and power but fail to notice the positive and negative terminals are reversed. Your factory cables won’t reach, and trying to stretch them is a recipe for disaster. Always double-check the terminal layout!

Forgetting About Cold Cranking Amps (CCA)

CCA is a measure of a battery’s ability to start an engine in cold temperatures (0°F / -18°C). The OEM battery has a specific CCA rating (around 210-230).

If you ride in cold climates or run a winch, look for a replacement with an equal or, ideally, higher CCA rating for more reliable starting power when you need it most.

Upgrading Your RZR 800 Battery: AGM vs. Lithium

The stock battery is fine, but technology has improved. Upgrading can give you more power, longer life, and better reliability. Let’s look at the two most popular upgrade paths.

The AGM Advantage (Absorbent Glass Mat)

AGM is the most practical and popular upgrade for most RZR owners. It’s still a lead-acid battery, but the electrolyte is absorbed in fiberglass mats instead of being a free-flowing liquid.

Benefits of AGM:

Spill-Proof and Position-Flexible: You can mount them in any orientation without worrying about leaks.
Superior Vibration Resistance: The packed construction makes them perfect for the harsh off-road environment.
Maintenance-Free: They are completely sealed, so you never have to check water levels.
More Power: AGM batteries typically offer higher CCA and better deep-cycle resistance than traditional flooded batteries.

The Lithium Leap (LiFePO4)

For the ultimate in performance, lithium batteries (specifically LiFePO4) are the top tier. They represent a significant investment but offer incredible benefits.

Benefits of Lithium:

Drastic Weight Reduction: A lithium battery can be up to 70% lighter than its lead-acid equivalent. That’s a significant weight saving on a UTV.
Massive Cranking Power: They deliver incredibly strong, consistent starting power.
Extremely Long Lifespan: A quality lithium battery can last 2-4 times longer than a lead-acid battery.
Low Self-Discharge: They hold a charge for months, making them great for vehicles that sit for extended periods.

The Catch: Lithium batteries are expensive and can be sensitive to charging systems. Ensure your RZR’s voltage regulator is working correctly, and consider using a lithium-specific battery tender.

Your 2008 Polaris RZR 800 Battery Size Care Guide

Buying the right battery is only half the battle. Following this simple 2008 polaris rzr 800 battery size care guide will maximize its lifespan and ensure it’s ready when you are. These are the 2008 polaris rzr 800 battery size best practices every owner should follow.

Regular Cleaning and Inspection

Once a month, take a quick look at your battery. Make sure the terminals are clean and tight. If you see any white or greenish powder (corrosion), disconnect the terminals (negative first!) and clean them with a wire brush and a baking soda/water solution. A clean connection is a happy connection.

Use a Smart Battery Tender

If your RZR sits for more than a couple of weeks, especially in the off-season, connect it to a smart battery tender or maintainer. This device keeps the battery at an optimal charge without overcharging it, preventing sulfation and dramatically extending its life.

Check Your Charging System

Your RZR’s stator and voltage regulator are responsible for recharging the battery while the engine is running. A faulty charging system can kill even the best battery. Periodically check the voltage at the battery terminals with a multimeter while the engine is running at a fast idle. You should see a reading between 13.5 and 14.5 volts. If it’s much lower or higher, you have a charging system problem that needs to be fixed.

Eco-Friendly Battery Disposal

When your old battery finally gives up, please dispose of it responsibly. Lead-acid batteries are highly toxic but also highly recyclable. This is a key part of having a sustainable 2008 polaris rzr 800 battery size mindset. Never throw one in the trash. Any auto parts store or battery shop that sells batteries is required by law to accept your old one for recycling, and they’ll often give you a credit for it.

Frequently Asked Questions About the 2008 Polaris RZR 800 Battery

What is the best replacement battery for a 2008 RZR 800?

For most users, a high-quality AGM battery in the YTX14AH-BS size is the best blend of performance, reliability, and value. Brands like Yuasa, Odyssey, and Duracell offer excellent options. If you’re a serious racer or want the absolute best performance and weight savings, a LiFePO4 battery from a reputable brand like Antigravity or Shorai is the ultimate upgrade.

How many Cold Cranking Amps (CCA) do I need?

The stock battery has around 210-230 CCA, which is the minimum you should accept. We recommend looking for a replacement with at least 250 CCA, especially if you ride in colder weather or use high-draw accessories like a winch or a large sound system.

Can I use a car battery in my RZR 800?

No, you absolutely should not. Car batteries are physically much larger and won’t fit. More importantly, they are not designed to withstand the constant, high-frequency vibrations of off-road use. A car battery will fail very quickly in a UTV.

How long does a 2008 RZR 800 battery last?

The lifespan of your battery depends heavily on its type, usage, and how well you maintain it. A standard flooded battery might last 2-3 years. A quality AGM battery, when properly maintained with a tender, can last 4-6 years. A premium lithium battery could last even longer, up to 8-10 years.

Choosing the right 2008 Polaris RZR 800 battery size is a foundational part of reliable off-roading. By understanding the specs, measuring for a perfect fit, and considering an upgrade to AGM or Lithium, you’re not just replacing a part—you’re investing in peace of mind on the trail.

Now you have the expert knowledge to confidently select, install, and maintain the heart of your RZR’s electrical system. Get that new battery installed, keep it maintained, and get back to what matters most.

Stay safe, ride hard, and we’ll see you on the trails!

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Thomas Corle

Founder & Automobile expert at FatBoysOffroad

Automobile expert and off-road enthusiast, sharing in-depth knowledge of vehicles, gear, and adventures. Helping readers make smart decisions and enjoy the thrill of off-roading safely and confidently.