Eunorau | Flash Extra Battery: 52V21Ah (2nd) | 52V17Ah (3rd) | Both | 52V-21AH-HYFX-D-RA4

Eunorau Flash Replacement Batteries — 52V 21Ah (Down Tube) & 52V 17Ah (Top Tube)

Overview

Two reliable lithium-ion battery options designed for the Eunorau Flash: a higher-capacity 52V 21Ah down-tube pack using HYFX-D LG3500 cells and a lighter 52V 17Ah Hailong top-tube pack. Both include a 4A charger and an integrated battery management system (BMS) for safer, balanced charging and riding.

Benefits

• Extend your ride — higher capacity means fewer stops to recharge and longer range per charge.
• Less worry about battery health — built-in BMS protects against short circuit, over-charge, over-discharge and over-current.
• Choose the right balance of weight and range — pick the 21Ah down-tube for maximum distance or the 17Ah top-tube for a lighter bike.
• Simpler charging — standard 4A charger for routine, predictable recharging times.
• More dependable rides on hills and longer trips thanks to consistent power delivery and cell balancing.

Features

• Compatibility: Designed to work with the Eunorau Flash e-bike.
• Two form factors: down-tube battery (21Ah) and top-tube Hailong battery (17Ah).
• Integrated BMS with cell balancing for safety and longevity.
• Includes a 4A charger for standard charging.
• Durable black finish that matches the bike’s aesthetics.
• Cycle life rated at approximately 500–800 cycles under normal usage.

Specifications

• Compatibility:
  • Eunorau Flash — https://eunorau-ebike.com/products/flash
• 52V 21Ah HYFX-D (LG3500) — Down-tube battery
  • Model: 52V21Ah lithium ion e-bike battery (HYFX-D LG3500)
  • Nominal Voltage: 52V
  • Rated Capacity: 21Ah
  • Weight: 13.9 lbs (?6.3 kg)
  • Standard Charge Current: 4A
  • Type: Down-tube battery
  • Color: Black
  • Cycle Life: 500–800 cycles
  • Charger: 4A charger included
  • BMS & Balance: Short-circuit protection, over-charge protection, over-discharge protection, over-current protection, cell balancing
• 52V 17Ah Hailong — Top-tube battery
  • Model: 52V17Ah lithium ion e-bike battery (Hailong)
  • Nominal Voltage: 52V
  • Rated Capacity: 17Ah
  • Weight: 10.5 lbs (?4.8 kg)
  • Standard Charge Current: 4A
  • Type: Top-tube (Hailong) battery
  • Color: Black
  • Cycle Life: 500–800 cycles
  • Charger: 4A charger included
  • BMS & Balance: Short-circuit protection, over-charge protection, over-discharge protection, over-current protection, cell balancing