Battery architecture shapes your product line, your warehouse, and your after-sales cost for years — and it is one of the hardest spec decisions to reverse. Here is how the two approaches compare when you are briefing an OEM.
The Two Designs
Removable. The pack sits in a lockable cradle — inside the down tube, or on a rear rack or seat-tube mount — and slides out with a key. The frame needs a cutout, a latch, and a contact plate.
Integrated. The pack is mounted inside the frame — usually the down tube — rather than on an external cradle. Some internally mounted packs are user-removable through a service port; others require workshop access. Charging usually happens through a port on the frame.
The line blurs in practice: a pack that removes through the underside of the down tube is internally mounted but still serviceable.
What Riders Notice
Charging convenience. Removable wins for anyone without ground-floor power. Carrying a pack upstairs beats hauling the whole bike. Integrated suits riders with a garage or secure workplace parking.
Theft. Removable packs are a frequent theft target: expensive, resellable, and easy to walk off with. Theft resistance on an in-frame design depends on the actual access and locking design — confirm whether removal requires a key, a tool, or a full workshop teardown before assuming it. The counterpoint is that many riders want to take the battery with them anyway, for security and to keep it out of extreme temperatures.
Aesthetics. Integrated reads as premium to many buyers. Removable reads as practical, and on cargo, utility, and rental fleets that is usually an advantage rather than a compromise.
Weight distribution. Rear-rack packs place mass high and rearward, dulling handling and loading the rack and rear wheel. In-tube removable and integrated packs both keep weight low and central — which matters more, not less, as you move to larger 48V/52V packs.
What It Means for Distributors
Spare SKUs. Every distinct pack shape, cell configuration, BMS, and connector is a separate SKU. Confirm pack compatibility across models and frame sizes, then set spare inventory using warranty and failure data.
Warranty. A removable pack is a clean swap: send a replacement, RMA the old unit, refurbish or scrap. An internally mounted pack can mean a frame-level repair if access requires a teardown — confirm the actual removal procedure with the OEM and negotiate a field-replacement protocol and diagnostic flow before launch, not after.
Lithium shipping. Loose packs move as dangerous goods, subject to UN 38.3 test documentation, state-of-charge limits, and carrier paperwork. A pack installed in a bike is often handled differently from one shipped alone — a distinction that matters every time you send a replacement to a dealer or end customer.
What to Specify in OEM Orders
Voltage platform. Standardize voltage within compatible product families. Mixing platforms fragments spare parts and confuses dealers.
Cell sourcing. Ask which manufacturer and model, whether cells are A-grade or graded/reclaimed, and what happens if that cell is discontinued mid-program.
BMS and interface. Confirm continuous and peak discharge current, and lock the connector type and keying — proprietary connectors generate support tickets.
Mechanical and documentation. Get a mounting drawing, an IP rating for the pack and contacts, and the UN 38.3 test summary for transport declarations.
A Real Battery Ladder: 48V to 72V on One Factory's Line
Abstract spec debates get easier when you compare catalogs side by side. As a catalog comparison, a battery ladder that steps with vehicle class — not one pack stretched across every model — often looks like this:
- 48V 13Ah — cargo trike (D-04).
- 48V 15Ah — fat-tire models such as the FT-09, the AWD dual-motor (50-mile range) and the FT-020 folder.
- 48V 20Ah — the broad middle of the range: mopeds, the low-step mid-drive, recumbents, sidecars, and the 1,000W Revenge EEC motorcycle.
- 48V 25Ah, or a 1,200Wh Samsung-cell version — mid-drive fat tire, where torque demands and range expectations both rise.
- Dual 52V 20Ah — the dual-battery flagship, a 100+ mile class build.
- 72V 32Ah lead-acid — a 1,500W motorcycle with roughly 80 km of range.
- 72V 40Ah Li-ion — a 3,000W EEC motorcycle.
Read the ladder as a sourcing map. Voltage climbs with speed class and controller headroom; amp-hours climb with range targets and payload. The 72V lead-acid step is the outlier worth noting: compare pack weight at equivalent usable energy, and compare cycle-life specifications under equivalent operating conditions, before choosing chemistry. Determine spare-pack SKUs from confirmed electrical and mechanical compatibility across the selected models — and budget spares accordingly.
Chargers and Controllers: The Hidden Pair
Specify the charger and controller alongside the battery to establish compatibility and clear support procedures. Real pairings from the same line show how tightly the three components are matched:
- 48V 2A charger — belt-drive folder and cargo trike.
- 48V 3A charger — 500W fat tire, moped, sidecar trike, and EEC motorcycle.
- 48V 4A charger — low-step mid-drive.
- 48V 5A charger — mid-drive fat tire, paired with a 48V 30A controller.
- Dual 52V 3A chargers — dual-battery flagship, paired with a 52V 45A controller.
- 72V 35A controller — the 1,500W motorcycle.
Controller current spans 48V 20A to 48V 35A across the standard range, stepping up to 52V 45A on the flagship. The general pattern: charge rate tends to rise with pack capacity, and controller current rises with motor power. A 5A charger on a 25Ah pack refills meaningfully faster than a 2A unit on a 13Ah pack, and the controller determines whether the pack can actually deliver the motor's peak draw.
Mismatched pairing costs real money. An under-spec controller may constrain performance on a high-draw motor; a charger's suitability depends on the pack's permitted charging current and protection system; a charger with the wrong connector or voltage keying invites a warranty claim. Confirm approved limits and compatibility for the trio — pack, charger, controller — and treat it as one specification, not three line items.
Consider charger current a market decision as well. A 2A charger suits a folder that charges overnight at a desk; a 5A or dual-charger setup suits a rider covering 100+ miles who needs a partial top-up midday. Charger spec is part of the product experience, not an accessory.
Removable at Scale: What Dual Packs Teach
The dual-battery flagship makes the dual-pack argument concrete: two 52V 20Ah packs, each with its own 52V 3A charger, feeding a 52V 45A controller on a 1,500W build with 20x4.0" KENDA tires. If a dual-pack design uses removable packs, it highlights several lessons that apply to any removable line.
Spare inventory planning. Two installed packs do not automatically mean two spare SKUs — confirm with the OEM whether the packs are physically interchangeable, and set stocking levels against observed failure data rather than assuming doubled demand.
Swap logistics. If the packs are identical and interchangeable, a rider can carry one spare and swap mid-ride instead of waiting on a charge — useful for rental and delivery fleets, once the OEM confirms it is supported.
Fleet implications. Removable packs let a fleet charge packs in a rack, away from the bikes, rather than tying up parking space with charging bikes. That is a meaningful cost lever at scale, though it requires disciplined pack tracking, since loose packs are easy to lose or misassign.
Failure isolation. Ask the OEM to confirm whether the bike can operate on a single pack and how the BMS handles mismatched pack states — do not assume a failed pack simply degrades range.
The trade-off is complexity: two packs to manage mean more to specify, more to test, and more to document — reasonable on a flagship, harder to justify on an entry commuter.
Integrated Where It Wins
Integration is not automatically the premium choice — it wins in specific use cases. The FT-020 belt-drive folder is a clean example: a 48V 15Ah Li-ion pack housed inside the frame, a Gates belt drive that eliminates chain lubrication, full suspension, and pedal assist up to 21 mph.
That combination targets comfort and urban riding, and every element reinforces the others. An in-frame pack keeps weight low and central. A belt drive removes chain maintenance and grease — the same rider who wants a clean, low-effort bike is the rider who does not want to service a drivetrain. Full suspension and a folder frame suit mixed pavement and rough paths.
Questions to confirm with the OEM on an in-frame design like this: how does the pack come out — service-port removal or full workshop disassembly? Is there an external cradle or contact plate that can corrode or rattle? Can the pack charge off the bike? What is the field-replacement procedure if the pack fails? An in-frame pack may resist theft better than an external one, but confirm removal and service access in writing before assuming it.
Match architecture to the rider's charging situation and storage reality first, then to styling.
What the Warranty Line Means for Packs
A common warranty line is one year on electrical components and two years on mechanical parts. Confirm in writing which category the battery, BMS and charger fall under.
For distributors, that one-year electronics window is the term to negotiate against, because it usually underruns how long packs actually stay in service. Points worth putting in the contract:
- Cycle-life threshold. Define a minimum cycle count and capacity retention (for example, capacity remaining after a stated number of full cycles) rather than relying on a time-only term.
- Capacity fade curve. Ask for the expected degradation curve at your rated discharge current, so you can set your own customer-facing language.
- Replacement protocol. Specify whether failures ship as complete packs, cells, or BMS boards, who pays freight, and whether the failed unit must be returned before credit.
- Diagnostic flow. Agree the evidence required — voltage readings, charger behavior, error codes — so claims are not adjudicated by guesswork.
- Field-replacement terms for integrated packs. If the pack is inside the frame, negotiate a swap-or-repair path that does not require shipping a whole bike.
- Storage and shipping conditions. Define acceptable state of charge and temperature range, and who bears loss in transit.
Also confirm which certifications your target markets require before the order is placed. CE, EN15194, and RoHS are commonly held, and specific models may additionally list CPSC or EEC. Certification is per-model and per-market; do not assume a platform-wide approval travels with a new frame or a new pack.
Battery Spec Sheet: What to Lock in Writing with the OEM
- 1. Nominal voltage and amp-hour capacity, with the exact cell configuration.
- 2. Cell manufacturer, model, grade (A-grade vs. graded/reclaimed), and single-source risk.
- 3. Continuous and peak discharge current, matched to the controller rating.
- 4. BMS limits: over-current, over-temperature, low-voltage cutoff, and balancing behavior.
- 5. Charger spec: voltage, amperage, connector type, and charge profile per pack SKU.
- 6. Mechanical interface: mounting drawing, latch and lock type, torque specs, and contact plate design.
- 7. IP rating for the pack, contacts, and charge port.
- 8. UN 38.3 test summary and material composition sheet for transport declarations.
- 9. Warranty terms: cycle-life threshold, capacity retention, replacement protocol, and freight responsibility.
- 10. Labeling and certification artwork approved for each target market (CE, EN15194, RoHS, and CPSC or EEC where applicable).
The Takeaway
Removable wins on serviceability, fleet handling, and simpler warranty swaps. Internal mounting can win on theft resistance and aesthetics, depending on the access and locking design. Decide who rides your bikes and who repairs them first — then write that decision into the spec sheet. Treat architecture, voltage, component compatibility, and warranty terms as related but distinct decisions, and make them before tooling, not after.