Lithium Batteries (Primary): How to Choose the Right Cell

Primary lithium batteries are non-rechargeable cells built for long life, high energy in a small package, and dependable performance in cold or hot environments. Common nominal voltages are 1.5 V (AA/AAA Li‑FeS2), 3.0 V (CR coin, CR123A), and 3.6 V (Li‑SOCl2 industrial cells). Use them when you need long shelf life, low self-discharge, or strong pulse capability without recharging.

When to Choose Lithium

• Need long storage or standby: typical shelf life 10–20 years (chemistry-dependent).
• Operate in extreme temperatures: many perform from -40°C to +60°C; some industrial cells to -55°C/+85°C.
• High energy with low weight: better Wh/g than alkaline and NiMH.
• Low self-discharge: suitable for meters, sensors, memory backup, and emergency gear.

Avoid if you require frequent recharging, must minimize upfront cost, or your device is restricted to rechargeable chemistries only.

Common Chemistries and Best Uses

Chemistry	Nominal V	Typical Formats	Temp Range	Best For	Notes
Li‑FeS2	1.5 V	AA, AAA	~ -40°C to +60°C	Consumer devices, flashlights, trail cams, cold-weather use	Direct alkaline replacement (AA/AAA) where allowed; strong pulse capability.
Li‑MnO2	3.0 V	CR coin (e.g., CR2032), CR2, CR123A	~ -20°C to +60°C	Cameras, key fobs, sensors, security devices	Widely available; good balance of energy and pulse current.
Li‑SOCl2	3.6 V	1/2AA, 2/3A, A, C, D (ER/LS types)	~ -55°C to +85°C	AMR/AMI meters, IoT/IIoT, memory backup, long-life sensors	Very long life and low self-discharge; limited pulse—use hybrid capacitor if needed.
Li‑SO2	3.0 V	2/3A, A, specialty cylindrical	~ -55°C to +70°C	Emergency, military, cold-start high-pulse loads	Higher pulse current than SOCl2, but lower energy density.
Li‑CFx (BR coin)	3.0 V	BR2032, BR1225, etc.	~ -30°C to +85°C	Long-life, low-drain electronics	Lower current than CR coins; better high-temp stability.

How to Choose

1. Match size and code: Use the exact format your device specifies (e.g., CR2032, CR123A, AA). Coin cells: CR = manganese dioxide; BR = carbon monofluoride.
2. Match voltage: 1.5 V lithium AAs can replace alkaline AAs in many devices. Do not substitute 3.0/3.6 V cells for 1.5 V cells unless the device allows it.
3. Load profile: For long, steady, low-current loads, Li‑SOCl2 excels. For short, high-current pulses (cameras, flash), choose Li‑MnO2 or Li‑FeS2.
4. Temperature: For severe cold (≤ -20°C), prefer Li‑FeS2, Li‑SOCl2, or Li‑SO2.
5. Shelf-life needs: Li‑SOCl2 offers the longest storage/standby life; CR coins and Li‑FeS2 also store well.

Typical Capacities and Examples

• AA Li‑FeS2: ~3000 mAh at 1.5 V (≈4.5 Wh)
• CR123A Li‑MnO2: ~1500 mAh at 3.0 V (≈4.5 Wh)
• CR2032 coin: ~220 mAh at 3.0 V (≈0.66 Wh)
• Li‑SOCl2 D cell: ~17–19 Ah at 3.6 V (≈61–68 Wh)

Actual usable capacity depends on discharge rate, cutoff voltage, and temperature.

Quick Runtime Estimates

Estimate runtime with: Wh = V × Ah; Runtime (hours) ≈ Battery Wh ÷ Device W.

• Headlamp (1 W) on one AA Li‑FeS2 (≈4.5 Wh): about 4–5 hours continuous.
• Wireless sensor averaging 50 µA at 3.6 V using 1/2AA Li‑SOCl2 (≈1.2 Ah, 4.3 Wh): roughly 4.3 Wh ÷ 0.00018 W ≈ 24,000 h (~2.7 years).
• Camera on one CR123A drawing 1 A during use (≈3 W): 4.5 Wh ÷ 3 W ≈ 1.5 hours of cumulative “on-time.”

Note: Many devices draw pulsed or intermittent current; real-world runtimes vary with settings and temperature.

Compatibility Tips

• Only replace with the chemistry/voltage your device supports. When in doubt, check the manual.
• Replace all cells in a series pack at the same time. Do not mix brands, chemistries, or old/new cells.
• Coin cells: CR vs BR are not always interchangeable; BR coins favor high temperature and very low drain.
• Some battery indicators are calibrated for alkaline and may read “low” sooner with lithium even when capacity remains.

Safety and Handling

• Do not recharge primary lithium batteries.
• Prevent short circuits: keep in original packaging or cover terminals during storage/transport.
• Keep coin cells away from children; ingestion is a medical emergency.
• Avoid crushing, puncturing, or exposing to heat; follow device polarity.

Disposal and Recycling

• Recycle through approved battery collection programs. Do not throw in household trash.
• Tape terminals before recycling to reduce short-circuit risk.

FAQ

Can I use lithium AA/AAA instead of alkaline?

Often yes. AA/AAA Li‑FeS2 cells are designed as 1.5 V replacements and work well in many devices, especially in the cold. Always confirm your device allows lithium cells.

What’s the difference between CR and BR coin cells?

CR uses manganese dioxide (higher current, common in remotes and key fobs). BR uses carbon monofluoride (lower current, better high-temp stability for long-life, low-drain applications).

How long do they last in storage?

Depending on chemistry and storage conditions, expect roughly 10–20 years (Li‑SOCl2 at the high end; CR coins and Li‑FeS2 typically 7–15+ years).

Why does my battery meter read low with lithium?

Some devices estimate remaining life based on alkaline discharge curves. Lithium maintains higher voltage longer, so gauges can misread state of charge.

Are primary lithium batteries safe to ship?

Yes, when properly packaged with terminals protected and in compliance with carrier regulations. For bulk/air shipments, follow all applicable rules.