There's no single “best” lithium cell — only the best cell for your load. Below are the standout 10 cells in the CellBench database, ranked by real discharge-test data: capacity, maximum continuous current, and energy density. Cells we've physically tested are marked Lab Tested; the rest use datasheet or estimated data, labeled honestly so you can weigh the source.
Best high-drain 21700
Highest continuous current of any 21700 in the database — the go-to for high-power packs (FPV, power tools, performance EVs).
Best high-drain 18650
Most continuous current you can pull from an 18650 here — strong choice when space is tight but the load is heavy.
Highest-capacity 18650
Most energy per cell in the 18650 class — maximizes range/runtime where current demand is moderate.
Highest-capacity 21700
The largest tank here — best range-per-cell for ebikes, powerwalls, and long-runtime builds.
Best lab-verified all-rounder
Our top balance of capacity and current among cells we've physically discharge-tested — real measured curves, not datasheet claims.
| # | Cell | Format | Capacity | Max A | Energy | Wh/kg | Data |
|---|---|---|---|---|---|---|---|
| 1 | Samsung INR21700-50E | 21700 | 5000 mAh | 9.8 A | 18.0 Wh | 261 | Estimated |
| 2 | Molicel INR21700-P42A | 21700 | 4200 mAh | 45 A | 15.1 Wh | 216 | Datasheet |
| 3 | Samsung INR21700-40T | 21700 | 4000 mAh | 35 A | 14.4 Wh | 206 | Estimated |
| 4 | Sanyo NCR18650GA | 18650 | 3500 mAh | 15 A | 12.6 Wh | 263 | Lab Tested |
| 5 | Sony US18650VTC6 | 18650 | 3000 mAh | 30 A | 10.8 Wh | 232 | Lab Tested |
| 6 | Samsung INR18650-30Q | 18650 | 3000 mAh | 15 A | 10.8 Wh | 237 | Datasheet |
| 7 | LG INR18650-HG2 | 18650 | 3000 mAh | 20 A | 10.8 Wh | 225 | Estimated |
| 8 | Molicel INR18650-P28A | 18650 | 2800 mAh | 35 A | 10.1 Wh | 219 | Datasheet |
| 9 | Sanyo UR18650NSX | 18650 | 2600 mAh | 30 A | 9.4 Wh | 213 | Lab Tested |
| 10 | Samsung INR18650-25R | 18650 | 2500 mAh | 20 A | 9.0 Wh | 205 | Datasheet |
It depends on the load. For maximum range at moderate current, the highest-capacity 18650 here is the Panasonic NCR18650GA (3500 mAh). For high-drain builds, the Molicel P28A sustains the most continuous current (35 A).
A 21700 holds more energy per cell and usually delivers higher current, so packs need fewer cells — but each cell is bigger and heavier. 18650s give you finer control over pack shape and weight distribution. The right choice depends on your voltage, current, and space constraints.
By measured and published specifications — capacity (mAh), maximum continuous current (A), and energy density (Wh/kg). Cells marked “Lab Tested” have real discharge curves measured on a Rigol DL3021 with 4-wire Kelvin sensing; others use manufacturer datasheet or estimated data, labeled honestly so you can weigh the source.
Range scales with capacity, so the highest-capacity cells win for range. The Samsung 50E (5000 mAh, 21700) packs the most energy per cell — model a full pack in the simulator to see real range numbers.