1/2 AA Batteries

1/2 AA (14250) Batteries: How to Choose the Right One

1/2 AA batteries—also known as 14250—measure about 14.5 mm diameter × 25.0 mm length. They come in several chemistries with different voltages and behaviors. Matching the chemistry and voltage your device specifies is critical; a 3.6V cell is not a drop-in replacement for a 3.0V cell.

Quick Comparison by Chemistry

Chemistry / Code	Nominal Voltage	Typical Capacity	Temp Range (approx.)	Shelf Life	Best For	Notes
Lithium Thionyl Chloride (ER14250, LS14250)	3.6V	850–1200 mAh	-55°C to +85°C	10–20 years	Utility/smart meters, security sensors, PLC/CMOS backup	Very low self-discharge; limited continuous current—use pulse-optimized cells or a buffer capacitor for radio bursts.
Lithium Manganese Dioxide (CR14250)	3.0V	500–750 mAh	-20°C to +60°C	7–10 years	General electronics, cameras, compact instruments	Higher pulse capability than many Li‑SOCl2 cells, but lower capacity and shelf life.
Lithium Iron Phosphate Rechargeable (IFR14250)	3.2V	200–350 mAh	-20°C to +60°C	N/A (rechargeable)	Frequent-use devices you can recharge	Long cycle life; requires LiFePO4-compatible charger and device tolerance for 3.2V nominal.
Li‑ion Rechargeable (ICR/INR14250)	3.6–3.7V	300–500 mAh	-20°C to +60°C	N/A (rechargeable)	Custom builds, hobby projects	Requires appropriate charger and protection; check device max voltage.
NiMH 1/2 AA	1.2V	300–600 mAh	0°C to +50°C	N/A (rechargeable)	Legacy or specialized 1.2V designs	Less common; only for devices designed for 1.2V cells.
Alkaline 1/2 AA (rare)	1.5V	300–500 mAh	0°C to +50°C	3–5 years	Low-drain, noncritical devices	Limited availability; verify size and contacts carefully.

When to Choose Each Type

• Choose 3.6V Li‑SOCl2 (ER14250/LS14250) for long life, wide temperature swings, and very low self-discharge (meters, alarm panels, industrial sensors).
• Choose 3.0V Li‑MnO2 (CR14250) when your device specifies 3.0V and needs better pulse current than many Li‑SOCl2 cells.
• Choose rechargeable (IFR/ICR/INR14250) only if the device supports rechargeable lithium voltages and you can maintain a charging routine.
• Use NiMH 1.2V or alkaline 1.5V only if explicitly required by the device. These are not substitutes for 3.0–3.6V cells.

Terminal and Mounting Options

Beyond chemistry, match the physical termination your device expects:

• Button top or flat top (handhelds vs. holders)
• Solder tabs or axial leads (board-mounted or wired assemblies)
• PCB pins/standoff mounts (meters and modules)

Ordering tip: “With tabs” usually means pre-welded nickel tabs for safe soldering; do not solder directly to battery cans without tabs.

Common Use Cases

• Smart/utility meters and data loggers (long unattended life)
• Security and alarm sensors, wireless contact switches
• PLC/RTC/CMOS memory backup in industrial equipment
• Remote environmental sensors (LoRa/ISM), GPS trackers
• Legacy cameras and compact instruments

Runtime Estimator

Approximate runtime (hours) ≈ capacity (mAh) ÷ average current (mA). Example: a 3.6V 1200 mAh ER14250 powering a 20 µA (0.02 mA) sensor: 1200 ÷ 0.02 ≈ 60,000 hours (~6.8 years). Real-world life will be lower due to temperature, self-discharge, and pulse loads.

• Li‑SOCl2 self-discharge: ~0.5–1%/year
• Li‑MnO2 self-discharge: ~1–2%/year
• High pulse loads (e.g., radio transmissions) may require a pulse-rated cell or an external capacitor.

Selection Checklist

1. Voltage and chemistry: Match the manual (e.g., 3.6V ER14250 vs 3.0V CR14250). Do not assume interchangeability.
2. Pulse current: For radios or beacons, choose pulse-optimized cells or add a buffer capacitor.
3. Temperature: For outdoor/industrial use, favor Li‑SOCl2 (down to -55°C) or confirm the required range.
4. Termination: Button/flat top, tabs, leads, or pins must match the device.
5. Maintenance plan: Primary lithium for long unattended life; rechargeable for frequent-use devices you can service.

Safety and Handling

• Never charge primary lithium (ER/CR) cells. Risk of fire or rupture.
• Do not mix chemistries or old/new cells in series packs.
• Store primaries in a cool, dry place (50–77°F / 10–25°C). Keep terminals covered to prevent short circuits.
• Rechargeables: use the correct chemistry-specific charger (LiFePO4 vs Li‑ion) and observe device voltage limits.
• Recycle batteries through approved collection points; do not incinerate.

Compatibility Notes

• 1/2 AA is the size; 14250 is the IEC dimension code. Common cross-references: ER14250/LS14250 (3.6V), CR14250 (3.0V), IFR14250 (3.2V), ICR/INR14250 (3.6–3.7V).
• Do not confuse 1/2 AA with N-size cells (12×30 mm, 1.5V) or 2/3 AA (longer cell).

FAQ

Is 1/2 AA the same as 14250?

Yes. 1/2 AA describes the size; 14250 is the IEC code for ~14.5 mm × 25.0 mm cells. Chemistry and voltage still vary by model.

Can I replace a 3.6V ER14250 with a 3.0V CR14250?

Not recommended unless the device explicitly supports both. A 3.0V cell may cause malfunction or inaccurate readings in circuits designed for 3.6V.

Are primary lithium 1/2 AA batteries rechargeable?

No. ER (Li‑SOCl2) and CR (Li‑MnO2) cells are single-use. Only IFR/ICR/INR14250 variants are rechargeable and require the correct charger.

What does “with tabs” or “axial leads” mean?

These indicate factory-welded metal tabs or wire leads for soldering or board mounting. Select the termination that matches your device.

How long will a 1/2 AA battery last in a sensor?

Low-duty sensors often run 5–10 years on Li‑SOCl2 cells, depending on reporting frequency, temperature, and signal strength. Use the runtime estimator above for a rough calculation.