Shop Batteries by Size

Find the right battery by matching size, voltage, and chemistry to your device. This guide explains common sizes, what they power best, and how to choose for runtime, temperature, and safety.

How to Choose the Right Battery Size

1. Match the size code first: Check your device, battery bay, or manual (e.g., AA/LR6, AAA/LR03, 9V/6LR61, CR123A/CR17345).
2. Confirm voltage: Do not substitute sizes or voltages unless the device explicitly supports it. Example: CR123A (3.0V) is not the same as 16340/RCR123A (3.6–3.7V).
3. Pick a chemistry for your use:
   • Alkaline: Low cost for remotes, clocks, toys.
   • Lithium primary (non‑rechargeable): Long shelf life, works well in cold/heat; ideal for cameras, sensors, flashlights.
   • NiMH rechargeable: Best for frequent use and high drain (game controllers, flash units). Choose low self‑discharge (LSD) for standby devices.
4. Estimate runtime: Hours ≈ battery mAh ÷ device draw (mA). Example: A 2000 mAh AA powering a 100 mA device ≈ 20 hours.
5. Consider environment: For cold weather (below 20°F/−6°C), prefer lithium primary cells; alkalines lose capacity in the cold.

Quick Size Reference

Size (Common Code)	Dimensions (mm)	Typical Voltage	Typical Capacity	Best Uses
AAA (LR03)	44.5 × 10.5	1.5V (Alkaline), 1.2V (NiMH)	Alkaline ~800–1200 mAh; NiMH ~600–1000 mAh	Remotes, small toys, wireless mice
AA (LR6)	50.5 × 14.5	1.5V (Alkaline), 1.2V (NiMH)	Alkaline ~1800–3000 mAh; NiMH ~1900–2700 mAh	Flashlights, game controllers, cameras, toys
C (LR14)	50.0 × 26.2	1.5V (Alkaline), 1.2V (NiMH)	Alkaline ~6000–8000 mAh; NiMH ~3000–6000 mAh	Lanterns, radios, instruments
D (LR20)	61.5 × 34.2	1.5V (Alkaline), 1.2V (NiMH)	Alkaline ~12,000–20,000 mAh; NiMH ~8000–10,000 mAh	Large flashlights, emergency radios
9V (6LR61/1604)	48.5 × 26.5 × 17.5	9.0V (Alkaline/Lithium); NiMH 8.4V or 9.6V	Alkaline/Li: ~500–1200 mAh (at low drain); NiMH: rated in mAh at 8.4/9.6V	Smoke alarms (check manual), multimeters, pedals
CR123A (CR17345)	34.5 × 17.0	3.0V (Lithium primary)	~1400–1700 mAh	Tactical flashlights, cameras, security devices
CR2	27.0 × 15.6	3.0V (Lithium primary)	~750–900 mAh	Compact cameras, rangefinders, medical devices
1/2 AA (CR14250)	25.0 × 14.5	3.0V (Lithium primary)	~500–1200 mAh (varies by chemistry)	IoT sensors, meters, memory backup
2CR5	45 × 34 × 17	6.0V (Lithium primary)	~1500 mAh	SLR cameras, medical/industrial equipment
CR‑V3	52 × 28 × 14	3.0V (Lithium primary)	~3000 mAh	Digital cameras, photo gear

Use This / Avoid This

AAA

• Use if: Space is tight; device draw is low (remote, thermometer).
• Avoid if: High drain or long runtime needed—choose AA or lithium-equipped device instead.

AA

• Use if: Versatile size; NiMH AA (1900–2500 mAh) excels in high‑drain devices used daily.
• Avoid if: Extreme cold and long standby—pick primary lithium AA for better shelf and cold performance.

C and D

• Use if: You need long runtime at moderate draw (lanterns, radios).
• Avoid if: Device is compact/portable—AA or built‑in rechargeable formats may be better.

9V

• Use if: Device requires snap‑top 9V (alarms, meters). Lithium 9V offers long shelf life.
• Avoid if: Your device forbids rechargeables—some 9V NiMH are 8.4V; check manual.

CR123A and CR2

• Use if: High power in a compact format is needed, and long shelf life matters (flashlights, optics).
• Avoid if: Your device expects a different voltage—do not replace CR123A with 16340/RCR123A unless approved.

Compatibility Notes

• Voltage matters: CR123A (3.0V primary) vs. 16340/RCR123A (3.6–3.7V rechargeable). Only use what the device supports.
• 9V rechargeables: Commonly 8.4V (7 cells) or 9.6V (8 cells). Verify your device tolerance.
• AA/AAA NiMH: Nominal 1.2V is normal and typically works where 1.5V alkalines are specified; some devices with strict cutoff may prefer lithium primary.
• Don’t mix: Avoid mixing brands, ages, or chemistries in the same device; replace in full sets.

Scenario-Based Picks

• TV remote/thermostat: AAA or AA alkaline; for frequent use, LSD NiMH.
• Game controllers/toys: AA NiMH 1900–2500 mAh; recharge in 2–4 hours on a smart charger.
• Emergency kit: Mix of AA/AAA alkalines plus lithium CR123A for compatible lights; store spares in original packaging.
• Outdoor sensors/trail cams: Lithium AA/CR123A for cold weather and long standby.
• Smoke alarms: Follow device guidance; lithium 9V primaries often provide multi‑year service. Do not use rechargeables unless specified.

Safety, Storage, and Disposal

• Store at room temperature, dry, and out of direct sun; avoid metal-to-metal contact (keep in cases or original packs).
• Do not charge non‑rechargeable batteries. Use the correct charger and do not leave charging unattended.
• Remove batteries for long‑term storage to prevent leakage.
• Recycle where available (local e‑waste or retail programs); tape terminals on lithium cells before recycling.

FAQ

Can I use lithium instead of alkaline in the same size?

Often yes, if the device allows it. Lithium primaries (e.g., AA lithium) provide better cold performance, lighter weight, and longer shelf life. Always follow the device manual.

Why does my device show low battery with NiMH rechargeables?

NiMH cells are 1.2V nominal (vs. 1.5V alkaline). Some devices have strict cutoff thresholds. Many modern devices work fine; if not, use lithium primaries or check for a firmware setting.

How long do batteries last in storage?

Alkaline: typically 5–7 years; lithium primary: up to 10+ years; NiMH LSD: retains 70–85% after 1 year. Store cool and dry.

What do codes like LR6 or CR17345 mean?

They’re IEC/ANSI codes indicating chemistry and size. Examples: LR6 = alkaline AA, LR03 = alkaline AAA, 6LR61 = 9V alkaline, CR17345 = CR123A lithium primary.

Are spacers/adapters a good idea?

Only use manufacturer‑approved adapters. Adapters can affect contact pressure and may not meet current demands. Never force a cell that doesn’t fit.