EM19 Battery Pack – Alloy Tube Hidden Down-Tube 36V/48V Li-ion

Brand: EM19 Alloy Tube
Compatibility: EM19
Mounting Type: Fully built-in in the frame down-tube
Removal & Locking: Pull-out system from motor side (no need to remove motor) with screw-bolt lock
Battery Cells: Samsung 21700 Li-ion, up to 40 cells (10S4P for 36V / 13S3P for 48V)
Voltage & Capacity Range:
• 36 V 20 Ah (27.5 – 42 V) – ~720 Wh
• 48 V 15 Ah (36 – 54.6 V) – ~720 Wh
Charging Time:
• 36V 20Ah: 6–7 h (3A, DC 2.1 mm connector)
• 48V 15Ah: 5–6 h (3A, DC 2.1 mm connector)
Certifications: CE, UN38.3
Weight: ~3.8 kg

Help me understand it:

Weight ~3.8 kg: Lightweight yet durable design, maintaining bike balance and easy handling without compromising capacity.

Pros & Cons

🔹 36V 20Ah (~720 Wh)

Pros:

• Higher Ah capacity = extended range at moderate speeds.

• Optimized for motors from 250W–500W.

• Lower stress on electrical components, promoting longer battery life.

• Ideal for endurance and commuting with consistent pedal assist.

Cons:

• Lower peak power compared to the 48V pack.

• Less suitable for steep inclines or high-load acceleration.

🔹 48V 15Ah (~720 Wh)

Pros:

• Higher peak power = superior hill-climbing and speed performance.

• More efficient with 500W–1000W motors.

• Stronger acceleration and torque for heavier riders or cargo.

• Better efficiency at sustaining high cruising speeds.

Cons:

• Slightly shorter range if ridden at the same output as 36V.

• Can accelerate wear on components not rated for 48V.

• Slightly higher replacement cost due to voltage-specific parts.

Expert Advice Summary

Go with 36V 20Ah if:

• You want longer range, smoother rides, and optimal efficiency.

• Your motor is 500W or less and you use pedal assist more than throttle.

Choose 48V 15Ah if:

• You want maximum acceleration, better climbing performance, and higher speed capability.

• You use a motor of 750W or more or regularly carry heavy loads.

EM19 Alloy Tube: Purpose-built for EM19 frames, offering a robust, secure, and service-friendly design.
EM19 Compatibility: Engineered to fit perfectly within the EM19’s down-tube without external brackets.
Pull-out Motor-Side Removal: Allows easy extraction without removing the motor, improving maintenance convenience.
Screw-Bolt Lock: Provides strong theft prevention and secure battery fitment.
Samsung 21700 Li-ion (40 cells): High energy density and long cycle life for demanding riders.
36 V 20 Ah / 48 V 15 Ah: Dual options to balance endurance and peak performance needs.
CE & UN38.3: Compliant with global electrical safety and transport regulations.

🔋 Battery Comparison: 36V 20Ah vs 48V 15Ah