10/11/2025
🔋Understanding Battery Pack Sizes & Capacities
Ever wondered what numbers like 18650 or 21700 really mean?
They’re not random — they refer to the physical size of the battery cell.
Common Cell Sizes:
•18650 = 18mm diameter, 65mm length
•21700 = 21mm diameter, 70mm length
Different sizes = different power capacity.
Typical Capacity Ranges (per cell):
•18650: ~2,000–3,500 mAh
•21700: ~4,000–5,000+ mAh
21700 cells are popular in electric vehicles because of higher energy density.
Battery Packs (combined cells) – example use cases:
•5,000 mAh: Compact power banks, small electronics
•10,000 mAh: Tablets, handheld devices, portable tech
•20,000 mAh+: Robotics, medical devices, industrial tools
•50,000 mAh+: Portable power stations, backup systems, energy storage
Choosing the right pack size ensures the best balance of capacity, weight, and power output for your application.
At Voltaplex, we design and manufacture custom lithium-ion battery packs to your exact requirements (voltage, capacity, BMS, form factor, certifications).
Schedule an expert consultation for custom battery packs: https://calendly.com/sam-abdelaal-voltaplex
Browse bulk individual cells: https://voltaplex.com/collections/battery-packs