No, CR2 and CR123A batteries are NOT interchangeable. While both are 3.0-volt cylindrical lithium cells with identical Lithium Manganese Dioxide (Li/MnO₂) chemistry, their physical dimensions and energy storage capacities are vastly different:
- CR123A (CR17345): Measures 17.0 mm × 34.5 mm with a high capacity of ~1,400 to 1,600 mAh.
- CR2 (CR15H270): Measures 15.6 mm × 27.0 mm with a compact capacity of ~800 to 850 mAh.
A CR123A is 7.5 mm taller (+28%) and 1.4 mm thicker (+9%) than a CR2. It physically cannot fit inside a CR2 battery compartment. Conversely, placing a CR2 into a CR123A slot will cause it to rattle loose, fail to contact the terminals, and even if bridged with a spacer, will deplete in roughly half the running time.
If you own an Arlo security camera, a high-lumen tactical flashlight, a Fujifilm Instax Mini instant camera, or a golf laser rangefinder, you have likely encountered cylindrical 3V lithium photo batteries. Because they share the "CR" prefix and supply 3.0 volts, many buyers assume they are variations of the same cell. In this technical comparison guide, DigiStoreSG breaks down the physical dimensions, energy ratings, device applications, brand cross-references, and a crucial safety warning regarding 3.7V rechargeables.
2. Comprehensive Technical Specifications: CR123A vs. CR2
| Specification | Panasonic CR123A (CR17345) | Panasonic CR2 (CR15H270) |
|---|---|---|
| Nominal Height | 34.5 mm (+7.5 mm taller) | 27.0 mm (Compact) |
| Outer Diameter | 17.0 mm (+1.4 mm wider) | 15.6 mm |
| Nominal Voltage | 3.0 Volts | 3.0 Volts |
| Typical Energy Capacity | 1,400 to 1,600 mAh (~1.85× energy) | 800 to 850 mAh |
| Total Stored Energy | ~4.50 Wh | ~2.45 Wh |
| Continuous Discharge (Max) | 1,500 mA (1.5 A) | 1,000 mA (1.0 A) |
| Pulse Discharge (Peak) | Up to 3,500 mA (High flash) | Up to 2,500 mA |
| Weight | ~16.5 to 17.0 g | ~11.0 to 11.5 g (35% lighter) |
| Operating Temperature | -40°C to +70°C | -40°C to +70°C |
| Shelf Life (Low Self-Discharge) | 10 Years (<1% loss/yr) | 10 Years (<1% loss/yr) |
3. Physical Geometry & The DIY Spacer Myth
Because both cells supply 3.0V, many online forums suggest bridging the 7.5 mm height gap of a CR2 using tin foil or metallic spacers to make it work inside a CR123A flashlight or security camera. This is strongly discouraged for several critical engineering reasons:
- Physical Jamming: A CR123A will never enter a CR2 battery compartment. Forcing a 17 mm cell into a 15.6 mm cylindrical chamber will crush battery insulation, shear plastic clips, and permanently damage the device.
- Radial Rattling & Intermittent Power: A CR2 inside a 17.0 mm CR123A chamber has 1.4 mm of lateral play. Under flashlight recoil, weapon mount shocks, or door vibrations, the battery moves sideways, causing sudden voltage cutoffs or sensor offline events.
- Resistance, Heating & Fire Hazard: DIY spacers (like rolled aluminium foil or neodymium magnets) introduce parasitic electrical resistance. In high-pulse devices like tactical flashlights (drawing 2A–3A) or camera strobes, this resistance causes rapid localized heating, potentially damaging battery seals.
- 50% Battery Life Penalty: Even if contact holds, a CR2 gives you only ~800 mAh instead of ~1,500 mAh. In Arlo wireless cameras, this means replacing batteries every 6–8 weeks instead of 3–4 months.
4. Device Application Guide: Which Battery Does Your Gear Need?
Chosen when long continuous runtime, high burst current, and multi-year sensor life are required.
- Arlo Wireless Security Cameras: Original Arlo Wire-Free (VMC3030), Netgear Arlo security systems (typically takes 4× CR123A).
- Tactical Flashlights & Weapon Lights: SureFire (Fury, Scout, X300), Streamlight (TLR-1, TLR-2, ProTac HL), Olight, Inforce.
- Commercial Alarm Sensors: DSC, Honeywell 5800 series, SimpliSafe motion sensors, 2GIG wireless door contacts.
- Night Vision & Thermal Optics: Tactical monoculars, laser designators, thermal weapon sights.
- Smoke & Carbon Monoxide Detectors: First Alert OneLink, Nest Protect (certain backup models).
Engineered for lightweight handheld optics, vintage 35mm cameras, and mini instant photography.
- Fujifilm Instax Cameras: Instax Mini 25, Mini 50S, Mini 70, and Instax Share SP-1 Smartphone Printer (takes 2× CR2).
- Golf Laser Rangefinders: Bushnell (Tour V3, V4, V5, V6, Pro XE), Callaway (300 Pro, 250), Nikon Coolshot, Garmin Approach Z80/Z82.
- Vintage 35mm Film Cameras: Canon EOS Rebel 2000, EOS Kiss, Nikon Pronea, Minolta Dynax/Maxxum, Olympus Stylus Epic.
- Compact Smart Home Sensors: Fibaro Motion/Smoke Sensor, Aqara Door/Window Sensor T1 (some versions), Eve Door Sensor.
- Laser Sights & Boresighters: Compact sub-compact pistol lasers (Crimson Trace, Viridian).
When shopping for replacement batteries, you will see rechargeable cells marketed as RCR123A (16340) or RCR2 (15270). Do NOT insert standard 3.7V lithium-ion rechargeable batteries into devices rated for primary 3.0V cells unless the manufacturer explicitly permits it!
- Overvoltage Hazard: A standard CR123A outputs 3.0V (fresh open-circuit ~3.2V). A rechargeable 3.7V 16340 cell charges up to 4.20V fresh off the charger! In an Arlo camera or flashlight using 2 cells in series, that jumps the operating voltage from 6.0V to 8.4V (+40% over-voltage), instantly blowing LED drivers and digital sensor boards.
- Film & Instax Cameras: Film camera motors, flash capacitors, and Instax ejector gears are strictly calibrated for 3.0V / 6.0V. Running 8.4V burns motor windings and permanently bricks vintage cameras.
- Safe Alternative: If you must recharge, purchase only regulated 3.0V LiFePO4 cells (nominal 3.2V) or modern rechargeable cells with built-in DC-DC step-down circuitry that locks the terminal voltage strictly at 3.0V. Otherwise, stick with genuine primary Panasonic CR123A or Panasonic CR2 cells.
5. Battery Brand Equivalents & Cross-Reference Table
Different battery manufacturers use proprietary model prefixes. Use the cross-reference table below to identify your battery regardless of brand:
| Manufacturer / Standard | CR123A Equivalent | CR2 Equivalent |
|---|---|---|
| Official IEC Standard | CR17345 | CR15H270 / CR15270 |
| Panasonic / Maxell / Sony | CR123 / CR123A | CR2 |
| Duracell (Ultra / Photo) | DL123A / DL123 | DLCR2 |
| Energizer (Photo) | EL123AP / 123 | ELCR2 |
| Kodak | K123LA | KCR2 |
| Varta | CR123A | CR2 |
| ANSI / NEDA Standard | 5018LC | 5046LC |
6. Best Practices for Singapore Climate & Safe E-Waste Disposal
Tropical Storage (Singapore Climate)
Singapore's average 80%+ relative humidity can cause terminal tarnish over long storage periods. Store your backup Panasonic CR123A and CR2 cells in their original sealed blister packs inside an airtight container or camera dry cabinet (45–55% RH) at room temperature (22–25°C). Avoid keeping spare cells inside hot vehicle gloveboxes.
ALBA E-Waste Recycling
Never throw depleted lithium batteries into regular household garbage chutes. In Singapore, tape the terminal ends with electrical tape to avoid accidental short circuits, and deposit them into official ALBA E-Waste collection bins situated at Community Centres, MRT stations, Harvey Norman, and Best Denki outlets across the island.
Need Fresh 3V Lithium Batteries in Singapore?
DigiStoreSG stocks 100% genuine Panasonic primary lithium batteries with verified 10-year shelf life. Dispatched promptly from our local Singapore warehouse.
Panasonic CR123A 3V Lithium Battery
Original CR17345 cylindrical cell, 1,550 mAh capacity. Ideal for Arlo cameras, SureFire tactical lights & home security sensors.
Panasonic CR2 3V Lithium Battery
Genuine CR15H270 photo power cell, 850 mAh capacity. Perfect fit for Fujifilm Instax Mini, Bushnell golf rangefinders & film cameras.
7. Frequently Asked Questions (FAQ)
CR123A vs. CR2 Battery: What Is the Difference and Can You Swap Them?
No, CR123A and CR2 batteries cannot be swapped or substituted for each other. While both produce 3.0 volts using Lithium Manganese Dioxide (Li/MnO₂) chemistry, their physical dimensions and energy storage capacities differ significantly. A CR123A (17.0 mm × 34.5 mm) is 7.5 mm taller and holds 1,400 to 1,600 mAh, whereas a CR2 (15.6 mm × 27.0 mm) holds only ~800 to 850 mAh. A CR123A will not fit inside a CR2 compartment, and a CR2 will fail to reach the terminal contacts in a CR123A tray, causing loose rattling, power disconnects, or circuit failure.