Downtube Battery Cases

Why buyers choose Downtube

Downtube housings are inserted into the tube itself rather than hung off a dock, so nothing shows on the outside of the frame. That makes them the default choice on city, commuter and step-through bikes — and the hardest family to re-tool, which is why we keep twelve body sizes on the shelf.

The range is organised by opening length, because that is the number that decides whether a pack fits a given frame. Openings run from 278 mm on the compact ALX143 up to 538 mm on ALX077B, covering 18650 packs from 40 to 104 cells and 21700 packs from 28 to 52.

Every model is quoted as an empty shell with the end caps, cover and latch as separate mouldings, so you can specify the assembly route your line already uses.

Also known as: buyers also know this family as Polly or Dolphin cases — Polly for the square-shouldered bodies, Dolphin for the slim long profile. The names describe the shape, not a single factory — our Polly, Dolphin and Shark size guide maps the dimensions to the names.

• Twelve body sizes, 278–538 mm — Match the opening to the frame, not the frame to the case.
• 18650 to 104 cells, 21700 to 52 — The widest capacity span of any family we mould.
• Separate caps, cover and latch — Assemble to your process, or take them loose.
• MOQ 1 piece — Test a single housing against your frame before committing.