Battery Guide

Your Complete Battery Reference

Find the Right Battery

Whether you need to replace a dead battery or understand battery specifications, we've got you covered with comprehensive size charts and comparisons.

Cylindrical Batteries

The most common battery types used in everyday devices.

Type Diameter Height Voltage Common Uses
AAA 10.5 mm 44.5 mm 1.5V Remote controls, small flashlights, toys
AA 14.5 mm 50.5 mm 1.5V Cameras, game controllers, flashlights
C 26.2 mm 50 mm 1.5V Flashlights, radios, toys
D 34.2 mm 61.5 mm 1.5V Large flashlights, radios, boomboxes
9V 26.5 × 17.5 mm 48.5 mm 9V Smoke detectors, guitar pedals, multimeters
18650 18.6 mm 65.2 mm 3.6-3.7V Laptops, flashlights, vapes, EVs
21700 21 mm 70 mm 3.6-3.7V Electric vehicles, power tools, flashlights
CR123A 17 mm 34.5 mm 3V Cameras, tactical flashlights, security devices

Button & Coin Cell Batteries

Small, flat batteries commonly found in watches, calculators, and small electronics.

Type Diameter Height Voltage Chemistry Common Uses
CR2032 20 mm 3.2 mm 3V Lithium Key fobs, motherboards, watches
CR2025 20 mm 2.5 mm 3V Lithium Car remotes, calculators, watches
CR2016 20 mm 1.6 mm 3V Lithium Key fobs, fitness devices
CR1632 16 mm 3.2 mm 3V Lithium Car keys, medical devices
CR1620 16 mm 2.0 mm 3V Lithium Key fobs, small electronics
LR44 / AG13 11.6 mm 5.4 mm 1.5V Alkaline Toys, calculators, laser pointers
SR44 / 357 11.6 mm 5.4 mm 1.55V Silver Oxide Watches, cameras, medical devices

Understanding Coin Cell Names

Coin cell battery names encode their size: CR2032 means 20mm diameter and 3.2mm height. The "CR" prefix indicates lithium chemistry.

Rechargeable Battery Types

Understanding different rechargeable battery chemistries.

NiMH (Nickel-Metal Hydride)

  • Voltage: 1.2V per cell
  • 500-1000 charge cycles
  • No memory effect
  • Best for: High-drain devices

Li-ion (Lithium-Ion)

  • Voltage: 3.6-3.7V per cell
  • 500-1000+ charge cycles
  • High energy density
  • Best for: Electronics, EVs, power tools

LiFePO4 (Lithium Iron Phosphate)

  • Voltage: 3.2V per cell
  • 2000+ charge cycles
  • Very stable & safe
  • Best for: Solar storage, RVs, marine

NiCd (Nickel-Cadmium)

  • Voltage: 1.2V per cell
  • 1000+ charge cycles
  • Memory effect (needs full discharge)
  • Best for: Power tools (legacy)

Quick Comparison

CR2032 vs CR2025

Same diameter (20mm), different thickness. CR2032 is 3.2mm thick with ~225mAh capacity. CR2025 is 2.5mm thick with ~165mAh capacity. CR2025 can sometimes fit in CR2032 slots but will have less runtime.

Alkaline vs Lithium (Primary)

Lithium batteries last longer, perform better in extreme temperatures, and have a longer shelf life (10+ years vs 5-7 years). However, they cost more than alkaline batteries.

18650 vs 21700

Both are lithium-ion cells. 21700 is larger (21mm × 70mm vs 18mm × 65mm) with 35-50% more capacity. 21700 is becoming the new standard for EVs and high-performance flashlights.

Battery Tips

Storage

Store batteries in a cool, dry place. Avoid extreme temperatures which can reduce capacity and lifespan.

Mixing

Never mix old and new batteries, or different brands/types. This can cause leakage or reduced performance.

Disposal

Recycle batteries properly. Many retailers accept used batteries. Never throw lithium batteries in regular trash.

Recommended Battery Products

Quality batteries and chargers we recommend for your devices.

Panasonic Eneloop Pro AA Rechargeable Batteries (4-Pack)

High-capacity 2550mAh rechargeable batteries, perfect for high-drain devices.

Panasonic Eneloop AAA Rechargeable Batteries (4-Pack)

Long-lasting rechargeable AAA batteries with up to 2100 recharge cycles.

Nitecore i4 Battery Charger

Universal smart charger for Li-ion, Ni-MH, and Ni-Cd batteries.

CR2032 Lithium Coin Batteries (10-Pack)

Reliable coin cell batteries for watches, key fobs, and small electronics.