Mercedes Key Battery Replacement: The Basics

Gilbert Smith
Dec 21, 2020

Scouring the web for Mercedes key battery replacement? If your locked outside your vehicle, this means you need a quick answer. If not, we’re sure you’ll still appreciate this.

What kind of battery does a Mercedes key fob use?

Your Mercedes key probably uses a pair of 3-volt CR 2025 batteries. But before you go buying a replacement, you’ll want to check your owner’s manual or remove the old batteries to make sure. Then you can take them to the shop with you to double-check.

So that leads us to another question: How do you get the old batteries out of there in the first place? Keep reading and we’ll let you know, and we’ll also cover where to find a replacement and what it should cost you.

Where Can You get a 3-Volt CR 2025 Battery?

Key Fob Batteries CR2025 With White Background

You can find 3-volt CR 2025s just about anywhere they sell batteries. Wal-Mart, gas stations, grocery stores, Amazon. This is a fairly common battery type for small electronics, so you’ll be able to find them all over the place.

Typically you’ll see them selling for around three bucks, or you can buy a pack of them and save some money.

You can find Mercedes-branded key fob batteries that are a little pricier, typically around five dollars each, but you’re only paying extra for the packaging. There’s no reason to buy a Mercedes CR 2025 when a Panasonic will do just fine.

Some drivers have reported that a CR 2032 actually works better, improving key fob range. The number refers to the physical size of the battery, 2.5mm for the 2025, 3.2mm for the 2032. The voltage is the same, so if the 2032 fits, it’ll work.

Mercedes Key Battery Replacement – How To

If You Have a SmartKey

Mercedes Benz key with black leather wallet

  1. Hold your key by the keychain.
  2. Pull on the sliding tab, and then pull the valet key out.
  3. Move the valet key over to the other side where it can be inserted into the fob, and push it down.
  4. Remove the back of the key fob.
  5. Put the new batteries in place, and then reassemble by doing the above steps in reverse order.

If You Have a Chrome Key

  1. Pull the bottom tab away from the fob until the key releases.
  2. Press the key into the tab in the fob’s flat end to open the cover.
  3. Replace the key and put it all back together.

You can always ask them to replace the battery at the shop, but it’s a cheap fix that should only take a couple of minutes, so why not do it yourself?

Once you have your new batteries in place and the fob reassembled, take it out to the car and give it a test. If you’ve properly replaced the batteries but the fob isn’t working, the issue might not be the batteries, so you’ll have to do some troubleshooting.

Owner Reviews

accountCircle Pt on November 6, 2023
Correct
Typical capacity (mAh) CR2025 160–165 CR2032 225 (CR)
avatar Gilbert Smith
Gilbert Smith is a New Mexico-based automotive journalist who enjoys writing about cars, trucks, and SUVs. He is a longtime contributor to Vehicle History and a member of the site's original content team when it launched.
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