CR2 Batteries (Category Guide)

CR2 batteries are compact 3V lithium photo cells (size code CR15270) used where small size, high pulse current, and long shelf life matter—think golf rangefinders, motion sensors, laser pointers, and compact/film cameras. This guide explains how to choose the right CR2, when to consider rechargeables, and what to expect for runtime and safety.

Key facts at a glance

• Size: ~27.0 mm (L) × 15.6 mm (D)
• Chemistry: Lithium Manganese Dioxide (Li-MnO2) for primary; Li-ion for rechargeables (RCR2)
• Voltage: 3.0 V (primary CR2); 3.6–3.7 V nominal (rechargeable RCR2)
• Capacity: ~700–900 mAh (primary); ~200–350 mAh (RCR2, typical)
• Shelf life: up to ~10 years (primary)
• Operating temperature: typically -20°C to +60°C; some extended-range primary cells are available
• Also labeled as: CR2, CR-2, CR15270; brand codes may include DLCR2 (Duracell), etc.

How to choose

1. Match your device spec: If it calls for “CR2 3V lithium,” use a primary CR2. Only use RCR2 (3.6–3.7 V) if the device manual lists rechargeables as compatible.
2. Consider usage pattern:
   • Infrequent/standby (security sensors, emergency spares): primary CR2 for long shelf life.
   • Frequent cycling (practice rangefinding, hobby use): RCR2 can reduce cost over time—if compatible.
3. Look for pulse performance: Rangefinders and some cameras draw short, high current bursts. Choose cells that specify strong pulse/drain performance.
4. Environment: For cold weather, pick primary CR2 rated for low temperatures (many work to -20°C; some to -40°C).
5. Quality & safety: Prefer reputable brands with fresh manufacturing dates; avoid mixing brands or ages in multi-cell devices.

CR2 vs. RCR2 (rechargeable): quick comparison

Feature	Primary CR2 (3.0 V)	Rechargeable RCR2 (3.6–3.7 V)
Best for	Standby devices, long storage, critical/occasional use	Frequent use in devices that tolerate 3.6–4.2 V
Typical capacity	~700–900 mAh	~200–350 mAh
Shelf life	Up to ~10 years	Must be recharged periodically
Up-front cost	Lower per cell	Higher (cell + compatible charger)
Cautions	Single-use; recycle properly	Higher voltage may damage 3V-only devices; use protected cells and correct charger

Use-case recommendations

Use case	Recommended type	Notes
Golf/laser rangefinders	Primary CR2	Needs strong pulse current; keep a spare. Expect months to a season for typical play.
Wireless motion/contact sensors	Primary CR2	Very low standby drain; 1–3 years is common depending on device and temperature.
Compact/film cameras	Primary CR2	Designed for 3.0 V; avoid RCR2 unless manual allows.
Laser pointers/small LEDs	Primary CR2 or RCR2*	*Use RCR2 only if rated for 3.6–4.2 V. Runtime per charge will be shorter than primary.
Frequent practice/testing	RCR2 (compatible only)	Lower cost over time; verify voltage tolerance and polarity.

What runtime can you expect?

Estimate hours ≈ capacity (mAh) ÷ average current (mA). Examples:

• Security sensor averaging 0.05 mA (50 µA): 700 mAh ÷ 0.05 ≈ 14,000 h (~1.6 years). Real-world: 1–3 years depending on signal bursts and temperature.
• LED device at 150 mA: 800 mAh ÷ 150 ≈ ~5 hours (continuous). High modes or cold weather reduce runtime.
• Rangefinder with short high-current pulses: total shots often measured in the low thousands per cell; varies widely by model.

Compatibility and sizing

• CR2 vs. CR123A: Not interchangeable. CR2 is shorter and narrower.
• RCR2 voltage: Full charge can reach ~4.2 V. Only use if the device manual supports rechargeables.
• Naming: CR2 = CR15270. Brand codes may differ but dimensions/voltage should match.

Care, storage, and safety

• Store in a cool, dry place (~20°C / 68°F). Keep spares in original packaging or a plastic case.
• Do not recharge primary CR2 cells. Do not mix old/new or different brands in the same device.
• Avoid short circuits—never carry loose batteries with keys or coins.
• Recycle at battery collection points or household hazardous waste sites; do not throw in trash.
• Air travel: carry spares in carry-on; protect terminals. Check airline and TSA/ICAO rules.

FAQ

• Are CR2 and CR123A the same? No. They have different dimensions and are not substitutes.
• Can I use a rechargeable RCR2 in a device that specifies CR2? Only if the device documentation lists rechargeables as compatible. The higher voltage of RCR2 can damage 3V-only electronics.
• How long do CR2 batteries last in storage? Quality primary CR2 cells can retain usable capacity for up to ~10 years when stored properly.
• What charger do I need for RCR2? A lithium-ion charger that explicitly supports RCR2 size and uses CC/CV charging. Use protected cells when possible.
• Why did my device drain the battery quickly? High-drain or frequent pulse use, extreme cold, or an aging cell can reduce runtime. Consider high-pulse rated primary cells or confirm RCR2 compatibility.