CR123A Batteries: How to Choose the Right Cell for Flashlights, Cameras, and Sensors

CR123A (aka 123, 123A, CR17345, DL123A, EL123A) is a compact primary lithium battery measuring about 17 × 34 mm with a nominal 3.0V and typical 1400–1600 mAh capacity. It excels in high-drain, duty-critical gear such as tactical flashlights, photo gear, and wireless security sensors thanks to high energy density, long shelf life (often up to 10 years), and strong performance in cold weather.

Is CR123A the Right Choice?

• Use CR123A if: your device explicitly calls for CR123A/123; you need long standby life (sensors, emergency lights); you operate in cold conditions; you want a reliable single-use cell for infrequent but critical use.
• Consider rechargeables (RCR123A/16340) if: you use the device daily and it is rated for 3.6–4.2V lithium-ion or 3.2V LiFePO4. Always check the manual—some optics, lights, and sensors are not compatible.
• Consider other formats: If your flashlight supports 18650/21700, those larger rechargeables usually provide longer runtime and lower cost per use.

Types and Compatibility

Type	Nominal Voltage	Typical Capacity	When to Choose	Notes
Primary CR123A (Lithium)	3.0V	1400–1600 mAh	Emergency kits, sensors, duty lights	Longest shelf life, strong pulse current; not rechargeable.
RCR123A / 16340 (Li-ion)	3.6–3.7V (4.2V full)	600–800 mAh	Frequent use in devices rated for Li-ion	Higher voltage can damage 3.0V-only devices; requires Li-ion charger.
RCR123A (LiFePO4)	3.2V (3.6V full) or regulated 3.0V	~400–700 mAh	Devices sensitive to overvoltage (if approved)	Lower capacity but safer voltage window; check compatibility.

Compatibility tip: If your device specifies only “CR123A” or “3V lithium,” stick with primary CR123A. Only use rechargeables if the manufacturer explicitly permits them.

How to Choose Within the Category

• Capacity (mAh): For lights/cameras, choose 1500 mAh class cells for longest runtime. For sensors, prioritize shelf life and low self‑discharge over small capacity differences.
• Discharge rating (CDR/pulse): High‑drain lights benefit from cells rated for 1–3 A continuous and higher pulse currents. Check datasheets for pulse capability.
• Operating temperature: Look for wide ranges (often around -40°F to 140°F / -40°C to 60°C). If you work in extreme cold, prioritize cells with tested low‑temp performance.
• Shelf life and date codes: Choose fresh stock with clear date or lot codes; expect up to 10 years when stored properly.
• Packaging: Bulk packs lower cost for fleets; retail 2‑packs are convenient for field kits.
• Brand and safety marks: Prefer reputable brands with safety certifications and robust venting designs for high‑drain use.

Quick Runtime Estimates

Back‑of‑the‑napkin math helps plan runtime. Actual results vary with driver efficiency, temperature, and step‑down behavior.

• Formula: Runtime (hours) ≈ capacity (Ah) × number of cells in series ÷ device draw (A).
• Flashlight example: 1× CR123A (1.5 Ah) at 1.0 A ≈ 1.5 h; at 2.0 A ≈ 0.75 h. Two cells in series don’t increase capacity—only voltage—so runtime stays ~the same at a given power level.
• Security sensor: Standby draw ~20–50 µA can yield multi‑year life. With periodic transmissions, plan for ~1–3 years per cell depending on signal strength and environment.

Pros and Cons

Pros

• High energy density in a compact size; strong pulse output for high‑drain bursts.
• Long shelf life (often up to 10 years) for emergency and infrequent use.
• Good cold‑weather performance compared to alkaline.

Cons

• Single‑use (primary) cells increase long‑term cost and waste if used daily.
• Less common than AA/AAA; availability can be limited in general stores.
• Rechargeable variants have lower capacity and higher voltage that may not be compatible.

Safety, Storage, and Travel

• Do not recharge primary CR123A cells. Use only approved chargers with rechargeables.
• Never mix old and new cells or different chemistries in the same device.
• Store cool and dry (around 68°F/20°C); avoid heat, direct sun, or metal contact. Use plastic cases; tape terminals before disposal.
• Air travel: Carry spare lithium batteries in your carry‑on only; protect terminals from shorting. Check airline/TSA rules before flying.
• Recycle at a battery collection point; do not incinerate.

FAQ

• Are CR123A and 16340 the same? No. 16340 (RCR123A) is rechargeable and higher voltage (up to 4.2V). Use only if your device allows it.
• Can I replace a CR123A with an AA? No. Size and voltage differ (CR123A 3.0V vs. AA 1.5V). Use the type specified by your device.
• Two CR123A vs. one 18650? Some lights accept either, but many do not. Only substitute if the manual lists both configurations.
• What temperature range is typical? Many primary cells operate roughly from -40°C to 60°C (-40°F to 140°F). Check the datasheet for exact limits.
• How long do they last in storage? Up to 10 years when stored properly. Choose fresh stock with recent date codes for critical gear.