Before we get into the weeds, here is what the datasheet promises:
The headline says 35A Max discharge. But look at the temperature graph. If you actually pull 35A continuously, the cell will hit 90°C+ (194°F) very quickly.
How does the Panasonic NCR21700T compare to alternatives? Here’s a quick reference table:
| Cell | Capacity | Max Continuous | Typical IR | Best For |
|------|----------|----------------|------------|----------|
| Panasonic NCR21700T | 5000 mAh | 15 A | 20 mΩ | High capacity, moderate power |
| Samsung 50E | 5000 mAh | 15 A | 25 mΩ | Similar, slightly lower discharge |
| Samsung 40T | 4000 mAh | 35 A | 12 mΩ | High power, low capacity |
| LG M50LT | 5000 mAh | 15 A | 22 mΩ | Comparable to Panasonic |
| Molicel P42A | 4200 mAh | 45 A | 10 mΩ | Extreme power (vaping, power tools) |
The NCR21700T stands out for its capacity-to-internal resistance ratio. It is one of the most energy-dense cells (≈261 Wh/kg) that can still deliver 15A continuously without overheating.
Panasonic is renowned for its safety mechanisms. The datasheet outlines several critical protections built into the cylindrical can:
The datasheet guarantees ≤30 mΩ (AC IR at 1 kHz). Fresh cells often measure 18–22 mΩ. This low IR reduces voltage sag and heating. Over time, IR will rise to ~40 mΩ near end-of-life (500 cycles). High IR is the first sign of a failing cell.
First, a bit of trivia. This cell is famously known as the "Tesla cell." When Tesla moved from 18650s to 21700s for the Model 3, Panasonic was their primary partner. While Tesla uses a slightly modified chemistry (the "Tesla-specific" variant), the off-the-shelf NCR21700T is the closest you can get to automotive-grade power.
For mechanical design, the datasheet provides exact dimensions:
Unlike some 21700 cells, the NCR21700T has no built-in protection PCB. You must add external overcharge, overdischarge, and short-circuit protection when designing a battery pack.
Panasonic Ncr21700t Datasheet May 2026
Before we get into the weeds, here is what the datasheet promises:
The headline says 35A Max discharge. But look at the temperature graph. If you actually pull 35A continuously, the cell will hit 90°C+ (194°F) very quickly.
How does the Panasonic NCR21700T compare to alternatives? Here’s a quick reference table: panasonic ncr21700t datasheet
| Cell | Capacity | Max Continuous | Typical IR | Best For |
|------|----------|----------------|------------|----------|
| Panasonic NCR21700T | 5000 mAh | 15 A | 20 mΩ | High capacity, moderate power |
| Samsung 50E | 5000 mAh | 15 A | 25 mΩ | Similar, slightly lower discharge |
| Samsung 40T | 4000 mAh | 35 A | 12 mΩ | High power, low capacity |
| LG M50LT | 5000 mAh | 15 A | 22 mΩ | Comparable to Panasonic |
| Molicel P42A | 4200 mAh | 45 A | 10 mΩ | Extreme power (vaping, power tools) |
The NCR21700T stands out for its capacity-to-internal resistance ratio. It is one of the most energy-dense cells (≈261 Wh/kg) that can still deliver 15A continuously without overheating. Before we get into the weeds, here is
Panasonic is renowned for its safety mechanisms. The datasheet outlines several critical protections built into the cylindrical can:
The datasheet guarantees ≤30 mΩ (AC IR at 1 kHz). Fresh cells often measure 18–22 mΩ. This low IR reduces voltage sag and heating. Over time, IR will rise to ~40 mΩ near end-of-life (500 cycles). High IR is the first sign of a failing cell. Panasonic is renowned for its safety mechanisms
First, a bit of trivia. This cell is famously known as the "Tesla cell." When Tesla moved from 18650s to 21700s for the Model 3, Panasonic was their primary partner. While Tesla uses a slightly modified chemistry (the "Tesla-specific" variant), the off-the-shelf NCR21700T is the closest you can get to automotive-grade power.
For mechanical design, the datasheet provides exact dimensions:
Unlike some 21700 cells, the NCR21700T has no built-in protection PCB. You must add external overcharge, overdischarge, and short-circuit protection when designing a battery pack.