For UAV engineers, choosing a 21700 cell is not simply a search for the highest current rating. Flight endurance, voltage under load, cell temperature, pack mass, cycle life, consistency and thermal protection all matter. A cell that looks strong in a short bench test may not be the best choice for a long hover, repeated missions or a tightly packed battery module.
The Amprius INR21700-60Q is a 6.0Ah, 3.5V full-tab 21700 lithium-ion cell rated at 21Wh. Its main attraction for drone battery packs is the combination of higher energy per cell and high-current capability. To see how the cell behaves beyond the specification sheet, SHLIZONE tested two samples at 0.2C, 30A, 48A and 60A.
Why drone customers care about more than maximum current
A multirotor or fixed-wing UAV battery experiences several different loads during one mission. Takeoff and aggressive climbing create short high-current demand. Hover and cruise create sustained load. Wind correction, payload changes and maneuvering add repeated current peaks. The pack must deliver all of these without excessive voltage sag or heat buildup.
For that reason, UAV buyers should evaluate at least six factors:
- Usable energy at the actual mission current, not only low-rate capacity.
- Voltage retention under load, because the flight controller and ESC respond to pack voltage.
- Cell and pack temperature during sustained discharge.
- Energy per unit mass, which affects payload and flight time.
- Cell consistency, internal resistance and matching quality.
- Cycle life under the intended charge rate, discharge rate and cooling conditions.
Amprius INR21700-60Q key specifications
According to the supplied INR21700-60Q product specification, the cell has the following ratings:
| Parameter | INR21700-60Q specification |
|---|---|
| Nominal / minimum capacity | 6000mAh |
| Nominal voltage | 3.50V |
| Nominal energy | 21Wh |
| Maximum weight | 72g |
| Initial AC impedance | 5mOhm maximum at 1kHz and 30% SOC |
| Maximum charge current | 12A (2C) |
| Maximum discharge at room temperature | 60A, not specified for cycle use |
| Higher-current condition | 110A with 80C temperature cutoff, not specified for cycle use |
| Pulse discharge | 150A for 2 seconds, not specified for cycle use |
| Discharge cutoff voltage | 2.50V |
| Charge / discharge temperature | 0 to 60C / -40 to 75C cell surface temperature |
| Cycle condition 1 | 800 cycles at 6A discharge, at least 80% initial capacity |
| Cycle condition 2 | 300 cycles at 30A discharge or 75C cutoff, at least 80% initial capacity |
At the specified maximum weight, 21Wh corresponds to approximately 292Wh/kg at cell level. This is a specification-based calculation, not a complete pack-level result. Busbars, holders, insulation, BMS, wiring, enclosure and cooling reduce the final pack energy density.
SHLIZONE independent discharge test
SHLIZONE tested two INR21700-60Q samples in a 25 +/- 3C environment. Each cell was charged at 3A using a CC-CV profile to 4.2V with a 120mA cutoff. The cells were then discharged to 2.5V at 1.2A, 30A, 48A and 60A. Capacity and maximum measured temperature were recorded.
| Discharge condition | Sample 1 capacity | Sample 2 capacity | Average capacity | Average maximum temperature |
|---|---|---|---|---|
| 0.2C / 1.2A | 6058mAh | 6057mAh | 6057.5mAh | Not recorded |
| 5C / 30A | 5889mAh | 5882mAh | 5885.5mAh | 66.0C |
| 8C / 48A | 5726mAh | 5691mAh | 5708.5mAh | 87.5C |
| 10C / 60A | 5541mAh | 5501mAh | 5521.0mAh | 99.5C |
Relative to the two-sample 0.2C average, the measured average capacity was approximately 97.2% at 30A, 94.2% at 48A and 91.1% at 60A.
These results show useful high-rate capacity, but they also show why temperature is a central design constraint. The 48A and 60A tests produced very high cell temperatures in this bench setup. These are stress-test observations, not recommended pack operating targets. A UAV battery using this cell requires validated cooling, cell spacing, temperature sensing and conservative current limits. The final limits must be established at pack level under the real mission profile.
Amprius 60Q vs EVE 50PL, Reliance RS50 and Tenpower 50XG
The following table compares manufacturer-stated values from the supplied 60Q specification and current publicly available competitor specifications. High-current ratings use different temperature limits and test definitions, so they should not be treated as directly interchangeable.
| Cell | Capacity | Nominal energy | Max weight | Initial AC resistance | High-current statement | Max charge |
|---|---|---|---|---|---|---|
| Amprius INR21700-60Q | 6000mAh | 21Wh | 72g | 5mOhm max | 60A at room temperature; 110A to 80C cutoff; 150A for 2s. High-current ratings are not for cycle use. | 12A |
| EVE INR21700-50PL | 5000mAh minimum | 18Wh | 68g | 5mOhm max | 70A to 2.5V with 75C recommended and 80C maximum cutoff in the current public sheet. | 10A |
| Reliance INR21700-RS50 | 4950mAh minimum / 5000mAh nominal | About 18Wh | 67g | 4mOhm max | 70A with 80C temperature cutoff; the manufacturer product page also lists at least 50C maximum pulse capability. | 15A |
| Tenpower INR21700-50XG | 5000mAh nominal / 4950mAh minimum | 18Wh | 71g | 4mOhm max | 40A without temperature cutoff; 90A with 75C cutoff; 140A for 3s. | 15A |
One important note concerns the EVE 50PL. Older public specification sheets listed higher 125A and 180A figures. A newer public sheet dated November 4, 2025 lists 70A maximum discharge and no separate pulse row. Buyers should match the specification revision to the exact production lot being qualified.
What the comparison means for UAV pack design
1. The 60Q offers more energy per cell
The 60Q is rated at 21Wh, compared with approximately 18Wh for the three 5Ah competitors. In the same series-parallel configuration, that is about 16.7% more nominal energy per cell position.
For a fixed energy target, the theoretical cell-count reduction is about 14.3%. Actual pack architecture may not allow that exact reduction because series voltage, parallel current, redundancy and mechanical layout still control the design.
2. The 60Q has a cell-level energy-density advantage, but not the lowest cell mass
Using maximum specified cell weight, the approximate nominal cell-level figures are:
- Amprius 60Q: 292Wh/kg
- Reliance RS50: 269Wh/kg
- EVE 50PL: 265Wh/kg
- Tenpower 50XG: 254Wh/kg
This calculation favors flight endurance and payload efficiency, but pack-level verification is still required. A cell with higher heat generation may require additional cooling or lower current limits, which can reduce the system-level advantage.
3. High-current labels are not directly comparable
The competitors do not use one common definition for maximum current. Some ratings require a 75C or 80C temperature cutoff; some distinguish continuous operation without a temperature cutoff; some are short pulse values. The 60Q specification also marks its highest-current conditions as not intended for cycle use.
For drone projects, the useful comparison is the delivered watt-hours, voltage sag and temperature under the customer's actual takeoff, hover, cruise and landing profile. A single maximum-amp number is not enough.
4. Cycle-life conditions matter
The 60Q specification states at least 80% initial capacity after 300 cycles at a 30A discharge condition. The current EVE 50PL sheet specifies at least 60% after 400 cycles at 40A. The Reliance RS50 sheet specifies at least 60% after 400 cycles at 40A or 30A under its listed charge conditions. Tenpower specifies at least 60% after 500 cycles at 40A.
These numbers cannot be ranked without considering charge current, rest time, cutoff voltage, cutoff temperature and end-of-life criterion. UAV operators should define mission-level end of life, for example maximum acceptable voltage sag or loss of flight time, instead of relying only on a capacity percentage.
Which cell fits which drone requirement?
The Amprius INR21700-60Q is especially interesting when the design priority is longer endurance or fewer parallel cells while still supporting substantial current. Our 30A test retained nearly 5.89Ah average capacity, making this a relevant operating point for further UAV pack evaluation.
The EVE 50PL, Reliance RS50 and Tenpower 50XG remain strong candidates when a project prioritizes a lighter individual cell, faster charging, a specific high-current rating or an already-qualified supply chain. The correct choice depends on the mission profile and the pack's thermal design.
Before selecting any of these cells, ask the supplier for:
- The exact datasheet revision and production lot.
- UN38.3 and required transport documents.
- Cell matching data for voltage, ACIR and capacity.
- A discharge curve at the expected UAV load.
- Temperature data using the intended cell spacing and airflow.
- Cycle data at the intended charge and discharge conditions.
Recommended validation process for drone battery teams
- Define the real current profile for takeoff, climb, hover, cruise and landing.
- Test single cells at that dynamic profile, not only constant current.
- Build a small representative module with the intended busbars and spacing.
- Measure voltage spread and temperature at several cell locations.
- Set BMS current, voltage and temperature limits with margin.
- Repeat the profile over enough cycles to observe resistance growth and capacity fade.
- Validate the complete pack in the aircraft under controlled flight conditions.
Frequently asked questions
Is the Amprius INR21700-60Q suitable for drone battery packs?
It is a promising candidate for UAV applications that need high energy per cell and substantial discharge capability. Suitability must still be confirmed in the complete pack because temperature, current sharing, vibration, cooling and the flight profile affect performance and safety.
How much capacity did the 60Q deliver at 30A?
The two SHLIZONE samples delivered 5889mAh and 5882mAh at 30A to a 2.5V cutoff, with maximum measured temperatures of 67C and 65C in the test setup.
Can the 60Q be operated continuously at 60A in a drone?
The supplied specification lists 60A at room temperature and marks the maximum-discharge condition as not for cycle use. In our two-sample bench test, 60A produced maximum temperatures of 97C and 102C. Do not use that test as a normal operating recommendation. Pack-level thermal validation and conservative protection limits are essential.
Does 6Ah automatically mean longer flight time than a 5Ah cell?
Not automatically. The 60Q has higher nominal energy per cell, but actual flight time depends on voltage under load, pack mass, propulsion efficiency, temperature, current profile and the usable voltage window.
Can the 60Q directly replace the EVE 50PL, Reliance RS50 or Tenpower 50XG?
Do not treat it as a drop-in replacement without validation. The cells differ in nominal voltage, mass, dimensions, current conditions, thermal limits, charge ratings and cycle definitions. The BMS, charger, busbars, spacing and enclosure may need to change.
Request samples and UAV battery support
SHLIZONE can support drone battery customers with INR21700-60Q sample inquiries, cell matching information, test-report discussion and pack-level application communication. Contact us with your series-parallel configuration, peak current, continuous current, target flight time, maximum pack mass and expected ambient temperature so we can recommend a practical next test.
Data and safety note
The SHLIZONE results in this article are based on two sample cells and are provided for engineering reference, not as a statistical production-lot guarantee. Competitor values come from publicly available specifications accessed in August 2026. Specifications may change by revision or lot. Lithium-ion cells require a qualified BMS, charger, mechanical design, thermal design and validated protection strategy. Do not use loose cells without appropriate engineering controls.
Sources for the website editor
- Supplied Amprius INR21700-60Q Product Specification, Version A, dated May 5, 2026.
- SHLIZONE Reliability Test Report FJ-QE-SY2026080401, dated August 5, 2026, sample size n=2.
- EVE INR21700/50PL specification dated November 4, 2025: https://storage.ua.prom.st/3278612_eve_inr21700_50pl_spec._p______2025.11.4.pdf.pdf.pdf
- Reliance INR21700-RS50 product page: https://www.reliance-battery.com/products-en.html
- Reliance INR21700-RS50 specification: https://www.rotorama.com/assets/docs/2ceb3c297304baa8ef9406f230e066a9/31843-1/inr21700-rs50-2025.1.2-1.pdf
- Tenpower INR21700-50XG specification: https://ttcells.com/spec_sheet/tenpower_inr21700-50xg_datasheet.pdf