Gens Ace 2S 7.4V 4000mAh LiPo Transmitter Receiver Battery JST-EHR G2S4000-EH

• Battery Type: Lithium Polymer (LiPo)
• Capacity: 4000mAh
• Voltage: 7.4V nominal (2S configuration)
• Cell Configuration: 2S1P (two cells in series, one cell in parallel)
• Connector Type: JST-EHR
• Weight: 151.1 grams
• Length: 69mm
• Width: 51mm
• Depth: 19mm
• Recommended Charge Rate: 0.2C (0.8A)
• Maximum Charge Rate: 0.5C (2A)
• Compatible Transmitters: Spektrum DX9, DX8, DX7S, DX7, Futaba
• Part Number: O-G2S4000-EH
• Supplier ID: B-RX-4000-2S1P
• Barcode: 6928493302606
• Application: Transmitter and Receiver battery pack

Overview

The Gens Ace Li-Po 2S 7.4V 4000mAh Tx/Rx battery with JST-EHR connector is a premium lithium polymer power solution specifically engineered for radio transmitters and receivers in the RC hobby. This compact 2-cell LiPo pack delivers exceptional capacity and reliability, making it an ideal choice for enthusiasts who demand consistent performance from their RC transmitter setups. Whether you're piloting an RC car UK-wide, managing a fleet of models, or flying RC aircraft, this battery ensures your radio system remains powered throughout extended sessions in the field.

Built by Gens Ace, a manufacturer recognised for quality energy solutions in the RC community, this 4000mAh capacity battery is designed to keep your transmitter and receiver operating at peak performance. The JST-EHR connector is a standard interface found on many popular radio systems, ensuring straightforward compatibility with compatible Spektrum DX9, DX8, DX7S, DX7 and Futaba transmitter models. With a 7.4-volt nominal output across two cells, this battery strikes an excellent balance between power delivery and safety, making it suitable for both seasoned RC enthusiasts and those new to the hobby who want reliable equipment from the start.

The 4000mAh capacity means extended operating time between charges—a critical advantage when you're enjoying multiple runs at the track, on the trail, or at an off-road bash site. Unlike alkaline or NiMH alternatives, lithium polymer technology provides consistent voltage throughout the discharge cycle, meaning your radio controls remain responsive and precise from the moment you switch on until the battery is depleted. This is particularly important when you're managing multiple RC vehicles or operating in competitive settings where radio performance directly impacts your driving experience.

Key Features

• 4000mAh Capacity — This substantial capacity delivers extended operating time for your transmitter and receiver, allowing you to enjoy longer sessions in the field without interruption, making it perfect for dedicated RC enthusiasts who want to maximise their hobby time without frequent recharging.
• 7.4V Nominal Voltage (2S LiPo Configuration) — The two-cell configuration provides the precise voltage required by most transmitter systems, delivering the electrical power needed for consistent radio performance and ensuring your control inputs remain sharp and responsive throughout the battery's discharge cycle.
• JST-EHR Connector — This industry-standard connector provides safe, reliable electrical connection to compatible transmitters and receivers, eliminating the need for adapter cables and ensuring a secure fit that won't accidentally disconnect during operation.
• Lightweight Design — Weighing only 151.1 grams, this battery pack adds minimal weight to your transmitter setup, preserving the balance and handling characteristics of your radio system whilst delivering the power you need for all-day operation.
• Compact Form Factor — With dimensions of 69mm length, 51mm width and 19mm height, this battery fits comfortably into transmitter battery compartments, making it the ideal drop-in replacement for standard Tx/Rx battery packs without requiring modifications to your equipment.
• Spektrum and Futaba Compatibility — Engineered for use with popular Spektrum DX series transmitters (DX9, DX8, DX7S, DX7) and Futaba radio systems, this battery integrates seamlessly into established RC control setups, providing peace of mind that your investment will work with your current equipment.
• Optimised Charging Parameters — With a recommended charge rate of 0.2C (0.8A) and a maximum charge rate of 0.5C (2A), this battery is designed for safe, controlled charging that extends cell lifespan whilst providing flexibility for both rapid top-ups and maintenance charging routines.
• Lithium Polymer Chemistry — LiPo technology provides superior energy density compared to older NiMH or alkaline alternatives, delivering more power in a smaller package whilst maintaining stable voltage output throughout the discharge cycle for consistent radio performance.

Technical Performance

This Gens Ace transmitter battery represents modern energy storage technology applied to RC radio systems. The 2S LiPo configuration (two cells in series) produces a nominal 7.4 volts, which is the standard operating voltage for the vast majority of contemporary transmitter systems used in RC car UK applications, RC aircraft operation, and general RC hobby pursuits. The 4000mAh capacity—measured in milliamp-hours—indicates the total energy storage available; at the recommended 0.2C charge rate of 0.8A, this battery can be safely charged in approximately five hours, making it convenient for overnight charging or quick top-ups between operating sessions. The maximum charge rate of 0.5C (2A) accommodates users who need faster charging times, though the manufacturer recommends the slower rate for optimal battery longevity. The JST-EHR connector is a miniature connector type specifically developed for transmitter applications where space is limited and reliability is paramount; this connector prevents accidental disconnection and provides secure contact surfaces that resist corrosion over time. The 151.1-gram weight and compact 69 × 51 × 19mm form factor ensure this battery integrates seamlessly into standard transmitter battery trays without requiring any modifications to your radio system. Lithium polymer cells deliver consistent voltage throughout their discharge curve, meaning your transmitter maintains full operating power until the battery reaches its cutoff voltage, unlike older battery chemistries that gradually fade during use. This consistent performance is particularly important during competitive RC events or extended field sessions where radio reliability directly affects your ability to control your vehicle safely and effectively.

What's in the Box

• Gens Ace 2S 7.4V 4000mAh LiPo battery pack with JST-EHR connector

Frequently Asked Questions

• Is this 7.4V LiPo battery compatible with my Spektrum DX9 transmitter? — Yes, Gens Ace specifically engineered this 4000mAh 2S pack with the DX9 in mind, along with the DX8, DX7S and DX7. The JST-EHR connector matches the standard Spektrum receiver connection, making installation straightforward. However, always verify your specific model's battery compartment dimensions and connector type before purchasing.
• What is the difference between this 4000mAh pack and smaller capacity alternatives? — The 4000mAh capacity provides significantly extended operating time compared to smaller packs. For comparison, Gens Ace produces 1400mAh and 2700mAh alternatives; the larger 4000mAh pack delivers three times the energy of the 1400mAh version, meaning you can operate your transmitter roughly three times longer between charges. This is particularly valuable if you're managing multiple RC vehicles or enjoying extended field sessions.
• How long does this battery take to charge? — Using the recommended 0.2C charge rate of 0.8A, expect a full charge in approximately five hours. If you need faster charging, the maximum 0.5C rate of 2A will reduce charge time to approximately two hours, though the manufacturer recommends the slower rate for optimal lifespan. Always use a LiPo-compatible charger with proper cell balancing capability.
• Can I use this battery with my Futaba transmitter? — Yes, this battery is designed for compatibility with Futaba transmitter systems and includes the standard JST-EHR connector that Futaba commonly employs. Verify your specific Futaba model uses this connector type before purchasing.
• What makes LiPo batteries better than the older NiMH transmitter batteries? — Lithium polymer technology offers several advantages: significantly higher energy density (more power in less weight), consistent voltage throughout discharge (your radio remains at full power until depletion rather than gradually fading), faster charging capability, and longer lifespan when properly maintained. LiPo batteries have become the industry standard for RC radio systems because they deliver superior performance across every metric.
• Is this suitable for beginners purchasing their first RC transmitter? — Absolutely. Whilst LiPo batteries require proper charging with a compatible LiPo charger and basic care, they are entirely beginner-friendly when handled correctly. The main difference from older battery types is using the correct charger—a LiPo-capable charger with balancing function—rather than a standard NiMH charger. Once you understand this requirement, LiPo operation becomes second nature.
• How long will this battery last before it needs replacement? — LiPo lifespan depends primarily on charge cycles and care. When charged at the recommended 0.2C rate and stored properly (at approximately 50% charge in a cool, dry location), this battery should provide 300-500 charge cycles of reliable performance. Faster charging and deeper discharges can reduce lifespan, whilst careful maintenance extends it significantly.

Why Buy from RC Model Shop?

RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the Li-Po 2S 7.4V 4000mAh Tx/Rx with JST-EHR today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.

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