In the overseas E-bike conversion kit and manufacturing supply chain, physical dimensional mismatch represents a critical technical pain point leading to high return rates and assembly delays. Many B2B buyers and kit distributors focus heavily on electrical metrics like voltage and capacity while overlooking rigid three-dimensional spatial constraints. When a battery pack cannot fit precisely into the bicycle frame's down-tube clearance, or interferes with the structure during riding vibrations, the mechanical integrity of the entire vehicle collapses. Based on standard Hailong case specifications, this guide provides a technical selection and spatial configuration blueprint.

Dimensional Blueprint: Decoupling the 367.5mm × 90.3mm × 89.5mm Physical Boundary

The standard Hailong case has established itself as a global benchmark in the conversion kit market due to its optimized physical envelope. This specific battery pack is constrained within 367.5mm (Length) × 90.3mm (Width) × 89.5mm (Height). This physical boundary is strictly engineered to maximize the layout of fifty 18650 cells in a 10S5P configuration while conforming precisely to the down-tube slope of standard hardtail or urban bicycle frame triangles.

During engineering selection, buyers must note that the 367.5mm length denotes the total assembled dimension including the mounting bracket. Because the Hailong shell utilizes a sliding rail interface, a longitudinal clearance of 20mm to 30mm must be reserved to allow the pack to slide out for charging. If the inner triangle frame clearance is exactly 367.5mm, end-users will face an architectural failure where the locked battery cannot slide open. Consequently, when reviewing frame blueprints, a minimum longitudinal safety clear zone of 395mm must be strictly maintained.

Spatial Compatibility: Checking Down-Tube Width and Bottle Cage Boss Alignment

Beyond longitudinal limits, the lateral 90.3mm width dictates riding interference mitigation. Standard European and North American urban frames feature down-tube diameters ranging from 38mm to 50mm. The Hailong shell's 90.3mm width dictates that the pack will protrude over the tubing width. Engineers must execute a collision check relative to front derailleur cable routing and crank arm rotational vectors. Ensuring a minimum mechanical safety gap of 5mm when the crank arms rotate to their closest proximity prevents friction and structural wear driven by accumulated tolerances.

Furthermore, the mounting plate relies on factory bottle cage bosses. The sliding plate’s slotted tracks are engineered to align with standard 64mm spaced blind rivet nuts. However, because this specific battery delivers up to 630Wh of energy—translating to several kilograms—securing it solely via two standard water bottle rivets risks loosening the rivets or tearing the thin-wall tubing under severe vibrational loads. Technical sourcing protocols dictate that commercial fleet setups must require a three-point reinforced plate or external heavy-duty clamps to distribute mechanical stress evenly across the down-tube wall.

Technical Integrity: Synergizing Standard Enclosure with Internal Electrical Specifications

Once physical dimensions are fully validated, B2B procurement managers must verify whether the enclosure’s mechanical structural integrity can support the high-density energy matrix within. This shell houses a tight 10S5P cell array ranging from 2500mAh to 3500mAh single cell profiles, yielding up to 36V 17.5Ah of continuous current.

The integrated 20A BMS management system generates thermal dispersion inside the sealed housing, which demands that the plastic compound meets flame-retardant standards (such as UL94-V0) and provides thermal conductivity control. Through precise physical dimensions selection and stringent parametric alignment, distributors can drive down supply chain friction caused by dimensional returns, optimizing conversion kit compatibility and long-term operating stability.