Panasonic NCR18650B

A 3.35 Ah 18650 cell rated for 4.9 A continuous, with the figures a pack design depends on and what each one was checked against.

Where these figures come from

Capacity and nominal voltage confirmed against the manufacturer datasheet. Continuous discharge and internal resistance are published typicals.

What it is for

High capacity and low current, and the cell most often specified by people who have read an old forum post. Its 4.9 A limit catches out a lot of first packs.

• Capacity: 3.35 Ah
• Nominal voltage: 3.6 V (2.5 V to 4.2 V)
• Continuous discharge: 4.9 A — 1.5C
• Internal resistance: 0.06 Ω
• Mass: 47.5 g

Questions

What is C-rate?

Current expressed as a multiple of capacity. A 3 Ah cell at 3 A is 1C; the same cell at 15 A is 5C. It is the number that decides whether a cell is being used gently or punished, and the rating that matters is the one on that cell’s own datasheet rather than a rule of thumb.

Do you recommend where to buy cells?

Not currently. Every cell page links to the manufacturer’s datasheet and nothing else. If supplier links are ever added they will be disclosed on the page, and the ranking will still be computed from electrical fit alone — a designer that recommends the cell paying the most commission is worthless, and it would look exactly like one that does not.