CR2 and CR123A (commonly called “123 Battery”) are both 3V lithium manganese dioxide primary cells, but they differ in physical dimensions and capacity. CR2 (15.6mm diameter × 27mm height) is smaller, fitting compact devices like laser pointers, while CR123A (17mm × 34.5mm) offers higher energy density for power-intensive applications like professional cameras. Their non-interchangeable sizes mandate strict compatibility with device battery compartments.
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What are the physical differences between CR2 and CR123A batteries?
CR2 batteries measure 15.6mm in diameter and 27mm in height, whereas CR123A batteries are larger at 17mm × 34.5mm. Both deliver 3V nominal voltage, but CR123A’s 30% greater volume enables higher capacity. Pro Tip: Always verify device specifications—forcing a CR123A into a CR2 slot risks damaging contacts.
The CR2’s compact design (coded as CR15266) suits space-constrained devices like penlights or medical sensors. In contrast, the CR123A (CR17335) leverages its larger form factor for extended runtime in DSLR cameras or tactical flashlights. For example, a security system requiring monthly battery swaps might use CR123A for longevity, while a mini keyboard remote opts for CR2. Critical note: Despite identical voltage, their size mismatch prevents cross-compatibility. Mechanical incompatibility often triggers BMS errors in smart devices, as seen in some digital thermometers attempting CR123A substitution.
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| Parameter | CR2 | CR123A |
|---|---|---|
| Diameter | 15.6mm | 17mm |
| Height | 27mm | 34.5mm |
| Volume | 5.1cm³ | 7.8cm³ |
How do capacity and runtime compare?
CR123A batteries typically provide 1,500–1,700mAh, outperforming CR2’s 800–1,000mAh range. This 70% capacity advantage makes CR123A preferable for high-drain devices. Pro Tip: Avoid mixing old/new cells in multi-battery setups—voltage imbalances accelerate degradation.
CR123A’s higher capacity stems from its increased volume, allowing thicker electrodes and more active material. For instance, in a 500-lumen flashlight, CR123A might deliver 90 minutes of runtime versus CR2’s 50 minutes. However, CR2’s smaller size enables innovative designs—some biometric locks use stacked CR2 cells to maintain security features in slim profiles. A common tradeoff emerges: runtime versus device portability. Thermal management also differs; CR123A’s larger surface area dissipates heat better during pulsed loads, as observed in laser rangefinders.
Which devices commonly use each battery type?
CR2 batteries power compact electronics: calculators, glucometers, and garage door openers. CR123A batteries dominate professional photography, night-vision gear, and emergency beacons. Pro Tip: Store CR123A in cool environments—heat above 60°C accelerates self-discharge by 300%.
CR2’s niche lies in miniaturized applications. Hearing aids, for example, often use CR2 due to its balance of capacity and size. Conversely, CR123A’s robust output supports devices like military-grade GPS units requiring -40°C operation. An emerging trend sees CR123A in smart home sensors with 10-year lifespans, leveraging its stable voltage curve. Interestingly, some high-end flashlights now accept both types via adjustable battery trays, though runtime varies drastically.
Can CR2 and CR123A be used interchangeably?
No—physical incompatibility prevents safe substitution. CR123A’s 1.4mm wider diameter and 7.5mm greater height make it physically incompatible with CR2 compartments. Warning: Forced insertion may bend terminals or cause short circuits.
Device manufacturers design battery trays with precise tolerances. A CR123A in a CR2 slot often jams, as seen in compromised blood pressure monitors where users reported damaged spring contacts. Conversely, CR2 in a CR123A device rattles, breaking connection during motion—a known issue in bike lights. Some third-party adapters claim to bridge the gap, but experts warn against them due to increased internal resistance and potential arc faults.
| Risk | CR2 in CR123A Device | CR123A in CR2 Device |
|---|---|---|
| Physical Damage | Loose connection | Forced compression |
| Electrical Issue | Undervoltage errors | Terminal shorting |
| Runtime Impact | 50% reduction | N/A (won’t fit) |
What about pricing and availability?
CR123A batteries cost 20–30% more than CR2 due to higher material costs, typically retailing at $2–$4 per cell. Both are widely available, but CR123A sees broader industrial adoption. Pro Tip: Bulk-purchase CR123A for frequently used devices—it reduces per-unit cost by 40%.
Market analysis shows CR2 dominance in consumer electronics (70% sales) versus CR123A’s specialty market (55% industrial). However, CR123A’s military/medical applications drive stricter QA standards—Panasonic’s CR123A cells undergo 23 quality checks versus 15 for CR2. Surprisingly, CR2 maintains popularity in photography backup systems, where its smaller size allows redundant power packs in camera grips.
Battery Expert Insight
FAQs
Yes, but rare. Li-ion RCR2/RCR123A exist (3.7V nominal), requiring compatible chargers. Never mix with primary cells due to voltage differences.
Do CR2 batteries expire?
Both types have 10-year shelf lives if stored below 25°C. CR123A’s lower self-discharge (2%/year) outperforms CR2’s 3%/year.
Can I use CR2 in smoke detectors?
Only if specified—most require CR123A for extended lifespan. Substitution risks early low-battery alerts.