iFlight Fullsend 6S 4000mAh Li-Ion 17.5C Battery with XT60 Plug for Long-Range

Longer Flight Time for FPV Cruising

Compared with traditional LiPo batteries, the iFlight Fullsend 6S 4000mAh Li-Ion battery delivers significantly longer cruising time for cinematic and long-range FPV flights. The high-energy-density 21700 Li-Ion cells allow pilots to fly farther while maintaining stable voltage output during low-throttle cruising.

High-Efficiency EVE 21700 Cells

Built with high-quality EVE INR21700-40PL cells, the Fullsend battery provides: Stable voltage delivery, lower voltage sag, High energy density, Better cruising efficiency, Reliable long-range performance.  Compared with low-quality Li-Ion packs, EVE cells maintain more consistent power output during extended flights.

Smooth Cruising Power with 17.5C Output

The 17.5C discharge rate is optimized for efficient cruising and cinematic flying rather than aggressive freestyle. This means: Stable cruising, Lower heat generation, Better battery efficiency, Longer flight duration.

Compact Design for Better Efficiency

With a compact 43×63×74mm form factor and only 430g weight, the Fullsend battery minimizes unnecessary payload while maximizing flight endurance. The XT60H connector ensures a secure and reliable connection for long-range flights.

Buying Guide: iFlight Fullsend 6S 4000mAh Li-Ion Battery

MEPSKING Expert Review: What the Flight Tests Show

Based on MEPSKING’s analysis of the supplied real-world flight-test footage, the main advantage of the iFlight Fullsend 6S 4000mAh Li-Ion battery is sustained cruising time rather than aggressive power delivery.

In a GEPRC Vapor D5 mountain-surfing test, the 4000mAh pack remained airborne for close to 15 minutes during a gentle flight. The same pilot normally obtained approximately six minutes of freestyle or seven minutes of cruising from a 1550mAh LiPo. Battery voltage was around 3.19V per cell after approximately 13 minutes, and the pilot landed before reaching the cells’ absolute lower-voltage limit.

A separate Chimera7 test used approximately 25–30% cruising throttle. The Fullsend pack completed slightly more than 17 minutes before the flight ended at around 3.3V per cell. Because the test ended following an unrelated aircraft issue, it should not be interpreted as a confirmed maximum-flight-time result.

These results show the battery’s endurance potential, but actual flight time will depend on aircraft weight, motors, propellers, wind, cruising speed and the voltage reserved for a safe return.

Real-World Flight Experience

The Fullsend 4000mAh feels best when the aircraft is flown smoothly. On a correctly configured 7-inch platform, it supports steady cruising and gradual power changes without requiring constant throttle correction.

The trade-off is its approximately 430g weight. Compared with a smaller LiPo, the drone carries more momentum, requires additional distance to slow down and may feel less responsive during rapid direction changes. Repeated punch-outs also demand the kind of high-current response for which a 6S1P Li-ion pack is not primarily designed.

For long-range cruising, cinematic routes and mountain surfing, this behavior is an acceptable trade-off for additional flight time. For racing or aggressive freestyle, a high-discharge 6S LiPo remains the better purchase.

iFlight Fullsend 4000mAh vs DOGCOM 4000mAh

In the supplied comparison test, the iFlight Fullsend and DOGCOM 6S 4000mAh Li-ion packs produced very similar results on the same Chimera7 platform when flown to approximately 3.3V per cell. Neither pack demonstrated a dramatic endurance advantage under these particular cruising conditions.

The practical buying decision should therefore be based on confirmed cell type, dimensions, connector, warranty support, availability and price. DOGCOM commonly specifies Samsung INR21700-40T cells, while the Fullsend battery has been produced with both EVE INR21700-40P 10C and upgraded 40PL 17.5C cells.

Version notice: iFlight states that the older 40P and upgraded 40PL versions may be supplied depending on inventory. Contact MEPSKING before ordering if a particular cell version or discharge rating is required.

Which Long-Range FPV Battery Should You Choose?

Li-Ion vs LiPo: Which One Should You Buy?

Choose the Fullsend Li-ion battery when your priority is maximum cruising time at moderate current. Its 88.8Wh capacity makes it suitable for smooth long-range routes, cinematic flying and endurance-focused exploration.

Choose a LiPo when your flying style includes racing, repeated full-throttle climbs, rapid acceleration or aggressive freestyle. Even when supplied with 17.5C 40PL cells, the Fullsend should still be treated as an endurance battery rather than a direct replacement for a high-discharge LiPo.

Browse the complete FPV battery collection to compare additional Li-ion and LiPo options.

Frame and Power-System Compatibility

The Fullsend 6S 4000mAh is best suited to efficient 6-inch and 7-inch FPV drones, including platforms similar to the iFlight Chimera7 and Nazgul Evoque F6. Some efficient 5-inch drones may carry it, but the additional weight can noticeably affect handling, braking distance and motor temperature.

Before ordering, confirm:

1. The drone and ESC support 6S voltage and a maximum charged voltage of 25.2V.

2. The battery deck can accommodate a 43 × 63 × 74mm pack.

3. The frame, motors and propellers can safely carry approximately 430g of battery weight.

4. The power lead uses an XT60-compatible connector with the correct polarity.

For additional setup guidance, read how to maximize FPV drone range.

Charging and Safe Return Advice

Charge the battery with a balance charger using a standard Li-ion program and a maximum voltage of 4.2V per cell, or 25.2V for the complete 6S pack. Do not use a 4.35V LiHV charging mode.

A charge rate at or below 1C means no more than 4A for a 4000mAh pack, provided the charger and battery label permit it. For storage, bring the cells to approximately 3.7–3.85V per cell and keep the pack in a cool, dry and fire-resistant location.

Do not plan a long-range route around the cells’ absolute minimum voltage. Begin the return flight early and aim to finish around 2.9–3.1V per cell after load and voltage sag are considered.

Final Purchase Recommendation

Choose the iFlight Fullsend 6S 4000mAh Li-Ion battery if you fly an efficient 6-inch or 7-inch FPV drone and want a practical balance between endurance, energy capacity and pack weight. It is particularly well suited to cinematic cruising, mountain surfing and long-range exploration.

Choose a 3000mAh Li-ion pack when lower takeoff weight and more responsive handling are more important. Choose an 8000mAh pack only when the aircraft can safely carry the additional payload. For racing and aggressive freestyle, select a high-discharge 6S LiPo instead.

Specifications

● Capacity: 4000mAh

● Voltage: 22.2V

● Cell Type: EVE INR21700-40PL

● Battery Capacity: 88.8Wh

● Cell combination: 6S1P

● Size: 43*63*74mm

● Weight: 430g

● Discharge rate: 17.5C

● Battery type: Lithium-ion

● Connector: XT60H

● Discharge wire plug and length: XT60H-F(AMASS)-130(±8）mm

● Charging cable plug and length: JST-XH2.54-7P-45mm

● Max Voltage (Fully Charged): 25.2V (4.2V per cell)

Recommended Parts

● HOTA S6 Ultra Dual Channel AC/DC Smart Charger

● SkyRC B6neo+ 240W Smart Charger

● MEPS Fireproof LiPo Battery Safety Bag

Disclaimer and Safety Guidelines

Safety Reminder: Supervise the battery charging process at all times and ensure to keep away from flammable materials. Improper charging may cause fire, and disassembling, damaging, using damaged batteries, or exposure to fire may lead to explosion. To ensure safety, please regularly check the battery's condition and stop using it immediately if any abnormalities are found.

Disclaimer: Users must carefully read and follow the safety instructions before using this product; any consequences resulting from improper use are the user's responsibility.

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