Duracell MN21 (A23/23A) Specialty Alkaline 12V Battery

The Duracell MN21—also labeled A23 or 23A—is a compact, non-rechargeable 12V alkaline battery designed for small RF transmitters and access devices that need short, strong power bursts.

What It Powers

• Car key fobs and vehicle alarm remotes
• Garage door and gate openers
• Wireless doorbells and chimes
• Security sensors and small transmitters
• Selected specialty electronics that specify A23/23A/MN21

When to Choose This Battery

Use if:

• Your device or manual specifically lists A23, 23A, or MN21.
• You need reliable 12V burst power in a small form factor for RF transmission.

Avoid if:

• Your device calls for A27 (smaller and not interchangeable).
• Your device uses coin cells (e.g., CR2032/2025/2016) or other 12V types.
• You want rechargeability (A23/MN21 is primary-only, not rechargeable).

Compatibility and Cross‑References

Common equivalent codes you may see on devices or packaging:

• A23, 23A, MN21
• 23AE, GP23A, E23A, V23GA, LRV08, K23A

Match the code stamped inside your device’s battery compartment for proper fit and radio performance.

Technical Specs

Expected Runtime and Shelf Life

• Typical use in a key fob: about 6–18 months with daily use; light/occasional use can last longer.
• Shelf life: up to 5 years when stored at room temperature in original packaging.
• Cold weather and frequent button presses reduce runtime; warm storage and accidental presses can also shorten life.

Installation

1. Confirm the code: A23/23A/MN21.
2. Observe polarity: align the “+” end with the + symbol in the tray.
3. Clean contacts: wipe gently with a dry, lint‑free cloth.
4. Seat firmly: ensure the door/cap closes fully without forcing.
5. Test function: verify range and responsiveness after installation.

Performance Tips

• Avoid pocket presses by using a key cover or locking buttons when possible.
• Keep contacts clean to maintain transmitter strength.
• If range is weak, reseat the cell, check polarity, and confirm you have A23—not A27.

Safety and Disposal

• Keep out of reach of children and pets; ingestion can be harmful. If swallowed, seek immediate medical help.
• Do not recharge, crush, short-circuit, or dispose in fire.
• Store at room temperature, away from heat and direct sunlight.
• Recycle or dispose of according to local regulations; do not mix with household trash where prohibited.

Troubleshooting

• No response after replacement: Recheck polarity and contact cleanliness; ensure the door is fully latched.
• Intermittent operation: Clean the contacts and confirm you’re using A23/MN21 (not A27). Inspect worn buttons or cracked housings.
• Vehicle remote still weak: Some vehicles require re-syncing after a battery change—follow your owner’s manual.

FAQs

Is A23 the same as MN21?

Yes. A23, 23A, and MN21 are common names for the same 12V alkaline format.

Can I use a CR2032 coin cell instead?

No. Coin cells are 3V and physically different; they are not compatible with A23 devices.

What’s the difference between A23 and A27?

A27 is smaller and has lower capacity. They are not interchangeable—use the code your device specifies.

How long will it last in a key fob?

Often 6–18 months with daily use; usage patterns, temperature, and transmitter design affect actual life.

Can I mix old and new batteries?

No. Replace the battery with a fresh A23/MN21 and avoid mixing used and new cells in any device.