For battery cells, review the product description for real-world current recommendations, testing notes, and application guidance. Manufacturer maximum ratings should be treated as limits, not the best target for long-term pack health.
Description
LinkData 55P 21700 Cell - 5500mAh 40A / 50A Lithium-Ion Battery
Datasheet max: 40A continuous / 50A with 80°C temperature cutoff
The LinkData INR21700S-55P 21700 5500mAh is a high-capacity, high-discharge lithium-ion cell designed for experienced battery pack builders who need strong runtime and high current capability in a 21700 format.
According to the LinkData INR21700S-55P specification, this cell has 5500mAh typical capacity, 5400mAh rated capacity, 3.6V nominal voltage, and a manufacturer discharge rating of 40A continuous without temperature cutoff or 50A continuous with 80°C temperature cutoff. It also lists an 88A pulse discharge rating for 10 seconds at 25±2°C and 50% SOC.
This is not a general-purpose loose consumer battery. It is best used in properly engineered battery packs or test fixtures with correct current sharing, over-current protection, over-discharge protection, temperature monitoring, and safe mechanical support.
Key Features
- 5500mAh typical capacity with 5400mAh rated capacity listed in the specification.
- 21700 cylindrical lithium-ion cell for advanced battery pack building.
- Manufacturer rating: 40A continuous without temperature cutoff, or 50A with 80°C temperature cutoff.
- 88A pulse discharge rating for 10 seconds at 25±2°C and 50% SOC as listed by the manufacturer.
- Low AC internal resistance: ≤4.5mΩ at 1kHz and 30% SOC.
- Strong capacity and power balance for demanding 21700 battery pack applications.
Specifications
| Store SKU | LD-55P-21700-5500-50A |
| Brand | LinkData |
| Model | INR21700S-55P |
| Product Type | Rechargeable lithium-ion cell |
| Size / Format | 21700 cylindrical cell |
| Typical Capacity | 5500mAh |
| Rated Capacity | 5400mAh minimum by standard charge and discharge |
| Typical Energy | 19.8Wh typical |
| Rated Energy | ≥19.4Wh by standard discharge to 2.50V at 25±2°C |
| Nominal Voltage | 3.6V |
| Maximum Charge Voltage | 4.20V |
| Discharge Cutoff Voltage | 2.50V datasheet cutoff. LinkData recommends system discharge voltage controlled above 2.50V, for example 3.00V. |
| Standard Charge | CCCV, 1C / 5500mA to 4.20V, 0.02C / 110mA cut-off at 25±2°C |
| Standard Charge Time | ≤1.5 hours for reference |
| Maximum Charge Current | 8A continuous charge listed in nominal specification. Charger design section states charge current should not exceed 10A per cell. |
| Standard Discharge | 0.2C / 1100mA discharge to 2.50V at 25±2°C |
| Manufacturer Max Continuous Discharge | 40A without temperature cutoff / 50A with 80°C temperature cutoff |
| Pulse Discharge Current | 88A for 10 seconds at 25±2°C and 50% SOC |
| Recommended Continuous Use | Use 40A or less per cell unless the pack has verified cooling, current sharing, and temperature cutoff. Do not design around 50A continuous without pack-level validation. |
| DC Internal Resistance | ≤13mΩ at 50% SOC, 1C discharge, 10 seconds |
| AC Internal Resistance | ≤4.5mΩ at 1kHz and 30% SOC |
| Weight | 68.5±1.5g |
| Dimensions | 21.35±0.15mm diameter x 70.7±0.2mm shoulder height with plastic film |
| Cell Wrap Color | Grey and purple |
| Operating Surface Temperature | Charge: 0°C to 60°C, recommended recharge release below 45°C / Discharge: -30°C to 80°C, must re-discharge release below 60°C |
| Storage Condition | Shipping state 20-30% SOC. 1 year: -20°C to 23°C; 3 months: -20°C to 45°C; 1 month: -20°C to 60°C; capacity recovery ≥90% |
| Long-Term Storage Guidance | Store in a low-humidity environment below 70% RH, free of corrosive gases. For long duration storage, 0°C to 20°C is recommended. |
| Rate Discharge Performance | 0.5C capacity ≥98%, 1C capacity ≥97%, 6C capacity ≥95% relative to standard discharge capacity |
| Temperature Discharge Performance | 55±2°C at 1C: capacity ≥97%. -20±2°C at 1C: capacity ≥80%. -30±2°C at 1C: capacity ≥70%. |
| Cycle Life | ≥1000 cycles at 1C charge / 1C discharge to 80% initial capacity. ≥600 cycles at 8A charge / 30A discharge to 60% initial capacity under manufacturer test conditions. |
| Power Performance | 250W discharge for 10 seconds at 50% SOC, ending voltage >2.50V and cell surface temperature ≤70°C |
| Battery Pack Protection Guidance | Battery packs should include overcharge protection, over-discharge protection, over-current protection, temperature monitoring, and protection against reverse polarity and short circuit. |
| Datasheet Status | LinkData INR21700S-55P Product Specification, Doc. No. PS-C043-001, Revision A1 |
Recommended Use
The LinkData 55P is recommended for experienced battery builders, pack designers, and testers working with high-capacity, high-discharge 21700 lithium-ion cells. It is a strong option for properly engineered battery packs where runtime and current delivery both matter.
For practical design, treat 40A per cell as the cleaner datasheet continuous reference point. The 50A rating is tied to an 80°C temperature cutoff and should only be used when the pack design, airflow, heat path, BMS limits, and application duty cycle have been tested and validated.
Real-World Performance Notes
The manufacturer data lists rate discharge capacity of at least 98% at 0.5C, at least 97% at 1C, and at least 95% at 6C when compared to standard discharge capacity. The datasheet also lists a 250W 10-second power test at 50% SOC with ending voltage above 2.50V and cell surface temperature at or below 70°C.
Real-world performance depends on temperature, cooling, current draw, pack design, nickel/copper busbars, wire gauge, BMS settings, cell matching, enclosure airflow, and application duty cycle.
Applications
- High-performance 21700 battery pack building
- E-bike and scooter packs with proper BMS and temperature monitoring
- Power tools, garden tools, robotics, and other high-drain equipment
- RC, UAV, and mobile power systems where high output and runtime matter
- Cell comparison testing and custom battery pack development
What Is Included
- 1 x LinkData INR21700S-55P 21700 lithium-ion cell
- No charger, BMS, holder, nickel strip, busbar, or wiring included unless stated separately
- Bulk packaging may vary depending on quantity and availability
Important Notes
- Manufacturer maximum ratings are limits, not automatic recommendations for long-term continuous operation.
- High-current use requires proper pack design, cell matching, current sharing, thermal design, and protection circuitry.
- Do not solder directly onto the cell terminals. Cells should only be assembled using proper spot welding methods.
- Do not mix cells from different batches, charge dates, or capacity ranks in series packs.
- For series packs, keep cell voltage variation within 20mV before assembly.
- Do not use damaged, dented, leaking, overheated, dropped, shorted, deformed, or rewrapped cells.
- Do not charge below 0°C or above 60°C.
- Do not discharge below the recommended system cutoff. LinkData recommends controlling system discharge above 2.50V, for example 3.00V.
DIY500AMP.COM Note: Build with current headroom.
Do not build a pack at the edge of the datasheet rating unless the pack has been tested at the full current, full duty cycle, and real operating temperature.
For safer pack design, use the 40A continuous rating as the main design reference and reserve the 50A rating for validated systems with temperature cutoff and thermal monitoring.
Do not build a pack at the edge of the datasheet rating unless the pack has been tested at the full current, full duty cycle, and real operating temperature.
For safer pack design, use the 40A continuous rating as the main design reference and reserve the 50A rating for validated systems with temperature cutoff and thermal monitoring.
FAQ
Is the LinkData 55P rated for 50A continuous discharge?
The datasheet lists 40A continuous discharge without temperature cutoff and 50A continuous discharge with 80°C temperature cutoff. DIY500AMP.COM does not recommend assuming 50A per cell is suitable for every pack. Use proper testing, cooling, current sharing, and BMS temperature protection.
Can this cell be used for e-bikes, scooters, drones, RC, or power tools?
Yes, when used in a properly engineered battery pack with correct parallel count, protection circuitry, thermal design, and safe current limits. It is not intended to be used as a loose standalone battery.
Does DIY500AMP.COM recommend using the maximum rating continuously?
No. Maximum ratings should be treated as limits. For long-term pack health, build with current headroom and verify temperature rise under the actual load profile.
What charger should be used with this cell?
Use a lithium-ion charger or pack charging system designed for 4.20V maximum cell voltage with proper CC/CV charging, full-charge detection, and protection circuitry. Do not trickle charge lithium-ion cells.
Can I solder directly onto this cell?
No. The datasheet states not to solder directly onto the cell. Battery pack assembly should use proper spot welding methods and correct pack-building practices.
Safety Warning for Lithium-Ion Battery Usage
Customers should have a clear understanding of lithium-ion battery handling and safety before making a purchase. Lithium-ion batteries are highly sensitive and may pose fire, burn, or explosion risks if improperly handled. Always charge batteries on fire-resistant surfaces, and never leave them charging unattended.
By purchasing, you assume full responsibility for any injury, damage, or loss arising from the incorrect use or handling of lithium-ion batteries or chargers. Compatibility with specific devices is not guaranteed. Only charge using a smart charger designed specifically for this battery type, and do not mix old or used batteries with new ones.
Important Usage Guidelines
- Not for use in e-cigarettes, vape devices, or similar devices.
- Risk of fire and explosion: misuse can cause batteries to ignite, explode, vent, or release harmful gases.
- Always use in a protected pack with appropriate circuitry and correct current limits.
- Store batteries in protective cases, away from metal items, to prevent short circuits.
- Do not use batteries with damaged wrappers, torn insulators, rust, odor, leakage, deformation, or visible damage.
- Follow the manufacturer's charging specifications. Avoid overcharging, over-discharging, trickle charging, or reverse polarity use.
- Do not alter, dismantle, puncture, crush, burn, immerse in liquid, or expose cells to open flame.
- Do not expose batteries to high temperatures, direct sunlight in vehicles, open flame, water, or other liquids.
- Do not carry loose cells in pockets, bags, or toolboxes where they can contact keys, coins, tools, or other metal objects.
- Batteries should only be spot welded by experienced builders. Do not solder directly onto battery terminals.
- Keep away from children and pets.
Users are expected to have battery-handling knowledge before purchasing. By using these batteries, you acknowledge that usage is solely at your own risk, and you take full responsibility for any resulting consequences.
For Resellers
Please ensure all safety information is passed along to end users to promote safe handling and proper use.
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Orders ship from Florida when inventory is available. Lithium-ion cells require proper handling, protected packs, correct chargers, and safe storage. Do not solder directly to battery terminals.
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