What Kind of Battery Does a Key Fob Take? A Guide to Common Types
By · Last updated: October 23, 2026
The Most Common Key Fob Batteries
That small remote in your pocket is a mini-computer that blends comfort and safety, and like any portable electronic device, it needs power According to automotive experts. The vast majority of car key fobs, transponder keys, and smart keys are powered by a small, flat, circular battery often called a “coin” or “button” battery. These are single-use lithium cells that provide long-lasting power in a compact size.
While the exact model varies by your car’s make and model, a few types appear more frequently than others. For example, a Reddit user in r/ reported that CR2032 batteries are used by the original equipment manufacturer for Subaru remote fobs. Another user in r/ noted that the CR1632 is a compatible battery model for some fobs. These batteries are widely available from auto parts stores, electronics retailers, and online sellers, with retailers like CarParts.com and Batteries Plus offering replacements for all major brands.
How to Find Your Fob’s Exact Battery Type
Before you buy a replacement, you need to confirm the exact battery your specific key fob requires. Using the wrong battery can prevent the fob from working or even damage it.
Check the Battery Itself
The most reliable method is to open the key fob’s plastic casing and look at the battery that’s already inside. The model number (e.g., “CR2032”) is almost always stamped directly onto the surface of the battery. Be careful when opening the fob, as it can be a delicate process. One automotive journalist described the task as feeling “like surgery,” warning that one wrong move could break the aged, brittle plastic clips that hold the shell together As reported by The Autopian. Use a small, flat tool like a screwdriver or the fob’s own emergency key blade to gently pry the seam apart.
Consult Your Owner’s Manual
If you’d rather not open the fob just to check, your vehicle’s owner’s manual is the next best place to look. As one automotive expert noted, reading the manual is the best way to learn about your key fob’s features and maintenance requirements According to Reader’s Digest. Look in the index for sections on “key fob,” “remote keyless entry,” or “battery replacement.”
A Brief History of Key Fob Power
Key fob technology has evolved significantly over the years, and so have the ways they are powered. Understanding the difference between older and modern keys can help you know what to expect. You can learn more about the Differences between transponder keys, smart keys, and remotes here.
The Standard: Disposable Button Batteries
For decades, the disposable button battery has been the standard. It’s a reliable and inexpensive solution, but it does mean dealing with an “unexpected nickel-and-dime expense every couple of years” As one analysis pointed out. This is the system most drivers are familiar with today.
An Experiment in Rechargeable Fobs
Some automakers have experimented with rechargeable keys. Starting in the 1990s, BMW introduced a key fob that used inductive charging. Drivers would insert the key into a slot in the ignition or dashboard, and the car would recharge the fob’s internal battery while driving. However, as proximity keys became popular in the mid-2000s, allowing drivers to keep the fob in their pocket, this system became obsolete. Since the fobs were no longer being inserted into the dash, BMW and other manufacturers largely returned to using replaceable button batteries According to a report in The Autopian.
The Future is Your Phone
The latest evolution is the digital car key, which eliminates the need for a physical fob altogether. Systems like Hyundai’s Digital Key 2 use a driver’s smartphone or smartwatch to unlock and start the vehicle, using the device’s own battery power As seen in vehicles like the 2026 IONIQ 5. This technology is becoming more common, especially in newer electric vehicles.
| Battery Model | Source | Reported Use |
|---|---|---|
| CR2032 | All About Wheels Snippet | Used by the OEM for Subaru remote fobs As reported by a Reddit user. |
| CR1632 | Just Cars Forum Snippet | Cited as a compatible battery model for some fobs By a Reddit user. |
Real-world cases and reports
Family Relies on Hidden Key After EV Battery Fails
In January 2026, an Antioch, California family experienced a harrowing 30 minutes when their infant was trapped inside their 2024 Cadillac Lyriq EV. The vehicle’s main 12-volt battery suddenly failed, causing the entire car to shut down and become unresponsive According to a report from ABC7 News. The electronic door handles wouldn’t deploy, and both the key fobs and the Cadillac mobile app were useless. After attempts by GM’s OnStar service to remotely unlock the car failed, the family eventually learned that a physical emergency key was hidden inside the key fob. They were able to use it to open the trunk and retrieve the baby As reported by SFist. This case underscores the critical importance of knowing how to access and use the mechanical key inside your fob, as it may be the only way to get into your car when its electronic systems fail.
The Delicate Surgery of Battery Replacement
While replacing a key fob battery sounds simple, it can be a frustrating task. An automotive journalist for The Autopian described the process of prying open the plastic shell as a major hassle. He noted that the clips holding the two halves together are often brittle and can easily break. Furthermore, he warned that some fobs have battery holders that can be sheared off the circuit board if too much force is applied, turning a simple battery swap into a need for a whole new fob In a 2025 article.
Cost of OEM-Supplied Batteries
A Reddit user in r/ shared a finding that a two-pack of CR2032 batteries, provided by the original equipment manufacturer of Subaru remote fobs, was priced at $25 According to a snippet from All About Wheels. While buying from a dealer ensures you have the exact right part, you can often find the same battery type from other retailers for a fraction of the cost.
Frequently asked questions
How often do I need to replace my key fob battery?
Most key fob batteries will last for several years. One automotive report suggests that replacing the battery is a small expense you can expect to encounter every couple of years According to The Autopian. Your car may give you a “low key fob battery” warning on the dashboard when it’s time for a change.
What happens if my key fob battery dies?
If your fob battery dies, you won’t be able to use the buttons to lock or unlock the doors. You will need to use the physical metal key blade hidden inside the fob to open the driver’s side door. To start the car, most vehicles have a designated spot on the steering column or near the start button where you can hold the dead fob; the car’s immobilizer can read the transponder chip inside the fob at very close range even without battery power. If your Key fob is not working, the battery is the first thing to check.
Can I replace the key fob battery myself?
Yes, most drivers can replace their own key fob battery. It typically involves prying the fob’s case open, swapping the old battery for a new one, and snapping the case shut. However, be aware that the plastic can be fragile, and there is a risk of damaging the fob if you’re not careful As one journalist warned.
Are key fob batteries rechargeable?
The vast majority of modern key fobs use non-rechargeable, disposable button batteries. While some older luxury cars, like certain BMW models from the 1990s and 2000s, featured fobs with rechargeable batteries, this technology was largely abandoned with the widespread adoption of proximity keys that no longer needed to be inserted into the dashboard to charge According to a report from The Autopian.
Replacing a dead battery is a quick and affordable fix. However, if your key fob is damaged, lost, or still doesn’t work after a battery change, you’ll need a full replacement. Before paying high dealership prices, it’s worth exploring your options for a more affordable aftermarket key fob that can save you hundreds of dollars. Learn more about the Differences between aftermarket and dealer key fobs to make an informed choice.
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