I’ve been looking at the datasheet (the 5300mAh / 15A cell), and I noticed something that keeps coming up in discussions – these cells can get surprisingly hot under moderate to high loads.
If you’ve spent any time in the DIY e-bike, high-drain flashlight, or advanced vaping communities, you’ve heard the whisper: “Get the NCR21700T. It runs hot.” panasonic ncr21700t datasheet hot
The is a high-performance, industrial-grade lithium-ion cell designed to meet the extreme power demands of modern high-drain applications . Originally developed for automotive and heavy-duty industrial use, this 21700 cell is often referred to as "hot" in the enthusiast community due to its exceptional 40A peak discharge capability and its frequent use in Tesla battery architectures. Panasonic NCR21700T Core Specifications I’ve been looking at the datasheet (the 5300mAh
Heat increases resistance, which increases voltage drop. Under a 30A load, the 4.2V cell drops to 3.2V instantly. The device thinks the battery is dead (low voltage cut-off triggers), so it shuts down. You pull the battery out, it measures 3.8V, but it is scorching hot. Lower your load or use a lower-resistance cell like the Molicel P45B. The device thinks the battery is dead (low
Standard 21700 cells (like the Samsung 50E) prioritize capacity, maxing out at 9.8A to 15A. The Panasonic NCR21700T is a different beast.
Here’s a forum-style post you can use or adapt for Reddit, DIY forums, or battery enthusiast groups.
The datasheet incorporates a and a CID (Current Interrupt Device) . Under abusive "hot" conditions (e.g., short circuit at 80°C ambient), the PTC activates at approximately 90°C, limiting current to <5A. However, for legitimate high-drain use, the datasheet strongly recommends active cooling: airflow of 2 m/s reduces surface temperature by 40% at 15A. Without such cooling, cycle life drops from 500 cycles (to 80% capacity) at 25°C to just 250 cycles at 45°C.