CR2 Battery Vs 123: What’s The Difference?

CR2 and CR123A are both 3V lithium manganese dioxide (Li-MnO₂) primary batteries, but CR2 (15.6mm diameter × 27mm height) is smaller and lower capacity (~800mAh) compared to CR123A (17mm × 34.5mm, ~1500mAh). CR2 suits compact devices like laser pointers, while CR123A powers high-drain equipment such as digital cameras and security systems. Both use spiral-wound electrodes for stable discharge but aren’t interchangeable due to size differences.

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What are the key physical differences between CR2 and CR123A?

CR2 batteries (model CR15266) measure 15.6×27mm, whereas CR123A (CR17335) is larger at 17×34.5mm. The 1.4mm diameter and 7.5mm height variances prevent cross-compatibility in battery compartments. For example, security cameras designed for CR123A can’t fit CR2 cells without adapters. Pro Tip: Always verify device specifications—misplaced cells may cause electrical contact failures.

Beyond size, CR123A’s extended height accommodates higher-capacity electrodes. Its 1500mAh rating nearly doubles CR2’s 800mAh, enabling longer runtime in power-hungry devices like tactical flashlights. However, the CR2’s compact profile makes it ideal for medical devices like glucose monitors where space is critical. Warning: Forcing larger CR123A into CR2 slots risks damaging spring contacts or causing short circuits.

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Do CR2 and CR123A share the same chemistry?

Both use lithium manganese dioxide chemistry, providing 3V nominal voltage and stable discharge curves. Their spiral electrode design supports pulse currents up to 3A, perfect for camera flashes. But why does CR123A last longer? Its larger volume holds more lithium anode material—approximately 1.8g vs. CR2’s 1.0g—directly increasing energy density.

Practically speaking, this chemistry enables storage for 10+ years with ≤2% annual capacity loss. For instance, emergency exit signs often use CR123A for this reliability. Pro Tip: Avoid mixing old and new cells—voltage disparities in multi-battery devices can trigger premature failure.

Can CR2 and CR123A be used interchangeably?

No—size incompatibility prevents safe substitution. While both deliver 3V, CR123A’s larger dimensions may jam in CR2 slots. Conversely, CR2 cells in CR123A devices will lose contact due to shorter height. Imagine trying to fit a AA battery into a AAA tray; the electrical connection becomes unreliable.

However, some devices with adjustable battery trays (e.g., certain flashlights) might accept both using spacers. Warning: Never stack CR2 cells to mimic CR123A length—this creates 6V potential, frying 3V-rated electronics.

Which devices commonly use each battery type?

CR2 excels in compact electronics: laser rangefinders, pen-sized medical devices, and key fobs. The Maglite XL50 flashlight famously uses CR2 for balanced size/runtime. CR123A dominates pro photography (Nikon SB-5000 flash), home security systems (Arlo cameras), and military gear (AN/PEQ-15 aiming lasers).

Consider battery availability: CR123A is more prevalent in North America, while CR2 sees wider use in Asian markets. Pro Tip: For cold environments, both perform well, but CR123A’s higher capacity better sustains devices in sub-zero temperatures.

How do capacity and runtime compare?

A standard CR123A provides 1500mAh at 100mA discharge, lasting ~15 hours. CR2 averages 800mAh under similar load, yielding ~8 hours. But what happens in high-drain scenarios? At 1A discharge, CR123A maintains 1.2V for 45 minutes vs. CR2’s 25 minutes—critical for strobe lights needing sustained bursts.

For low-power devices like calculators, CR2’s smaller size suffices. However, trail cameras capturing night-vision videos demand CR123A’s endurance. Transitional Tip: Always carry spares—CR123A’s higher capacity doesn’t negate the need for backups during extended field use.

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