26650 Lithium Battery: Specifications, Discharge Rates, Chemistry, and OEM Pack Design
The 26650 lithium battery is a cylindrical cell measuring 26.0mm in diameter and 65.0mm in length. It is commercially engineered in two primary chemistries: (1) Ternary NMC (3.6V/3.7V nominal, 4.20V cutoff), delivering capacities of 4,800mAh to 5,500mAh with continuous discharge rates from 15A to 50A (3C–10C) for high-lumen tactical lighting, power tools, and portable medical carts; and (2) LiFePO4 (3.2V nominal, 3.65V cutoff), delivering 3,000mAh to 3,600mAh with > 2,000 cycles for solar energy storage and security telemetry. Its substantial 26mm diameter provides ultra-low AC internal impedance (≤ 15mΩ) and exceptional heat distribution.
1. 26650 Chemistry Comparison: Ternary NMC vs. LiFePO4
Choosing the correct 26650 cell chemistry depends upon target duty cycle and environmental extremes:
| Parameter | 26650 Ternary Li-ion (NMC) | 26650 LiFePO4 (LFP) |
|---|---|---|
| Nominal Voltage | 3.6V – 3.7V | 3.2V |
| Standard Capacity Range | 4,800mAh – 5,500mAh | 3,000mAh – 3,600mAh |
| Upper Charge Limit | 4.20V ± 0.03V | 3.65V ± 0.03V |
| Discharge Cutoff Limit | 2.75V – 3.00V | 2.00V – 2.50V |
| AC Internal Resistance (1kHz) | ≤ 18 mΩ | ≤ 20 mΩ |
| Cycle Life (80% DoD) | ≥ 800 Cycles | ≥ 2,000 Cycles |
| Average Cell Weight | Approx. 95g ± 3g | Approx. 86g ± 3g |
2. Dimensional Comparison: 26650 vs. 18650 vs. 21700
While the 18650 remains ubiquitous, the 26650 delivers over double the energy capacity of standard 18650 cells in a single enclosure. This allows OEM pack builders to reduce the number of parallel connections, lowering spot-welding labor and simplifying BMS cell balancing circuitry.
Featured Industrial Battery Packs & Solutions
Factory-direct Grade-A lithium battery models engineered for commercial and industrial OEM/ODM projects.
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