Polly DP-9 DIY Downtube E-Bike Battery Case & Enclosure Kit (Holds Up to 91x 18650 Cells) – Universal Aluminum Alloy Shell with Cell Holders, DC Charging Port & Key Lock Mount

Build or re-case a custom high-capacity e-bike power pack with the Polly DP-9 Downtube DIY E-Bike Battery Case Kit. Designed specifically for custom lithium battery builders, off-road e-bike upgrades, and DIY battery repairs, this empty casing accommodates up to 91 individual 18650 cells (such as 10S9P for 36V, 13S7P for 48V, or 14S6P for 52V pack configurations).

Constructed from a lightweight yet durable combination of extruded aluminum alloy and impact-resistant ABS plastic, the Polly DP-9 mounts securely to standard water bottle boss threads on your bike frame. Featuring a standard DC charging socket, built-in power switch interface, and dual-key anti-theft locking mechanism, this case provides a professional factory appearance for your custom battery build.

⚠️ Important Product Notice & Compatibility Information

THIS IS AN EMPTY CASING KIT (DIY HARDWARE ONLY):

• NO BATTERY CELLS INCLUDED: This product contains only the physical enclosure, inner cell matrix brackets, key lock, and base rail. It does not include lithium-ion battery cells, BMS protection boards, or wiring assemblies.

• Dimensions Check: Overall outer case dimensions measure 370mm x 90mm x 140mm. Please verify frame clearance inside your bike's front triangle before ordering.

🚴 Perfect for Custom DIY Pack Builds

• 36V Systems: Build up to a massive 10S9P cell configuration for maximum amp-hour capacity.

• 48V Systems: Build up to a high-capacity 13S7P pack configuration.

• 52V Systems: Build up to a high-voltage 14S6P pack configuration.

🚀 Key High-Performance Features

• Expanded 91-Cell Capacity: Maximize your energy density with internal cell holder grids designed to cleanly isolate and lock up to 91x 18650 cells into position.

• Aluminum Alloy & ABS Enclosure: Extruded aluminum side walls combined with high-grade polymer end caps shield your custom pack against frame vibration, road debris, and impact.

• Universal Downtube Base Rail Mount: Fits directly onto standard frame water bottle mounting holes for balanced center-of-gravity weight distribution.

• Integrated Key Lock Security: Includes an integrated steel locking mechanism with 2 physical safety keys to prevent theft when parked.

• DC Charging Socket Port: Standardized DC charging port interface simplifies connection to dedicated lithium-ion chargers.

📊 Technical Specifications Matrix

⚙️ Assembly & Building Guidelines

1. Cell Matrix Arrangement: Spot-weld your 18650 cells into series/parallel groups using the included internal spacer holders to maintain safety air gaps.

2. BMS Wiring & Insulation: Install your Smart BMS protection board, ensure all balance leads are properly insulated, and fit protective fish-paper insulation inside the aluminum shell.

3. Closing & Mounting: Secure the outer end caps using screws, mount the base rail onto your e-bike frame, slide the completed case onto the rail, and lock with the key.

📦 Package Contents

• 1 x Polly DP-9 Empty E-Bike Battery Case (Black)

• 1 x Internal 18650 Cell Matrix Spacer Set (Up to 91 Cells)

• 1 x Downtube Base Mounting Rail

• 2 x Anti-Theft Lock Keys

Build your custom high-capacity e-bike pack today. Select your kit quantity below, click Add to Cart, and start building!