E-Flite’s RV-7, Apprentice STS, and Slow Ultra Stick are standout models, each with their own unique flight characteristics. In this guide, we’ll delve deep into battery recommendations that complement and enhance the distinctive attributes of these three RC airplanes, ensuring they can unlock their full potential in the skies.
HRB 4S 3300mAh 60C 14.8V

Brand: HRB
Voltage: 14.8V
Capacity: 3300mAh
Discharge Rate: 60C
Connector: XT60 Plug
Size: 135mm x 42mm x 30mm
Weight: 343g
E-Flite RV-7 1.1m: Known for its balance between slow, scale-like flights and high-energy aerobatics, the RV-7 demands a battery that can keep up. The HRB 4S, with its extended run time and faster top speeds, ensures the RV-7 can perform both gentle glides and daring maneuvers seamlessly. The minimal swelling means the battery remains stable even when the plane is pushed to its aerobatic limits.
Apprentice STS 1.5m: As a modern-day evolution of a favorite club trainer, the Apprentice STS requires consistency, especially for new pilots. The HRB 4S’s no voltage sag, even under throttle, ensures a steady flight experience, enhancing the SAFE technology features and making the learning curve smoother and more enjoyable.
Slow Ultra Stick 1.2m: This aircraft’s hallmark is its “mild to wild” performance. Whether flying slowly in tight spaces or performing aggressive aerobatics, the HRB 4S delivers. Its ability to maintain cool temperatures even after intense flights ensures the Slow Ultra Stick can transition between its diverse flying modes without missing a beat.
Build and Quality: Compared to many cheaper alternatives I’ve used, the HRB 4S stands out. Its excellent construction ensures longevity, making it a reliable choice for regular flyers. Its resistance to heating, even after demanding flights, speaks volumes about its quality and safety.
Zeee 14.8V 4S 50C 3300mAh

Brand: Zeee
Voltage: 14.8V
Capacity: 3300mAh
Discharge Rate: 50C
Connector: XT60 Plug
Size: 131mm x 43.5mm x 29mm
Weight: 348g (±15g)
E-Flite RV-7 1.1m: This aircraft, celebrated for its balance between scale-like flights and energetic aerobatics, truly comes alive with the Zeee battery. The battery’s incredible power and burst potential ensure that the RV-7 achieves both lofty ascents and rapid aerobatic transitions smoothly.
Apprentice STS 1.5m: As a foundational trainer, the Apprentice STS needs a battery that offers consistency and reliability. The Zeee battery’s ability to maintain power, even when put through rigorous flight routines, complements the Apprentice’s learning-centric design. New pilots can thus have extended and stable flight sessions, benefiting from the Apprentice’s SAFE technology features.
Slow Ultra Stick 1.2m: The Slow Ultra Stick’s dual-character performance, transitioning from calm flights to aggressive aerobatics, demands a battery that can keep pace. The Zeee 4S, with its astounding power and zero signs of swelling even after intense use, ensures the Slow Ultra Stick remains agile and responsive throughout its flight.
Robustness and Quality: I’ve pushed this battery to its limits, especially with my EDF jets, and it has consistently surpassed expectations. It handles the demand effortlessly, and the absence of swelling indicates its superior build quality and safety. Furthermore, the voltage variance of less than 0.02V across all cells ensures consistent energy delivery, vital for maintaining the aircraft’s performance and stability.