Custom Battery Pack OEM: Process, MOQ and Samples

This page sets out exactly how a custom battery pack OEM project runs at DIDIDEDE – what we need from you, what you get back, how long it takes and what it costs to start. If you have read our battery pack manufacturing capability and want the mechanics, this is the next page.

Key takeaways

  • The sequence runs: enquiry and spec sheet, feasibility and cell selection, BMS and communication, mechanical design, quotation, then a sample built and bench tested in about two weeks.
  • Minimum order quantity is 3 units for prototype and sample builds. Standard housings need no tooling; bespoke enclosures are quoted separately and only when required.
  • What we need from you: nominal voltage and capacity, continuous and peak discharge current, charge voltage and current, maximum dimensions or a drawing, connector and pin-out, communication protocol, IP and temperature requirements, target cycle life and annual volume.
  • Six variables move the unit price – cell brand and grade, capacity and current, enclosure, BMS and firmware, certification, and quantity. Two quotations for “the same” 48V pack commonly differ by 30%.
  • If you only know half the specification, send what you have: most projects start from a photo of the existing pack plus the motor controller rating.

The process, step by step

  1. Enquiry and spec sheet. You send the electrical and mechanical requirements. A one-page spec is enough to start; we will ask for the rest.
  2. Feasibility and cell selection. We confirm the chemistry and cell format – LiFePO4 for cycle life and thermal stability, NMC where energy density decides – and size the string configuration.
  3. BMS and communication. Protection thresholds, balancing, and the protocol your vehicle or inverter expects (CAN, UART, RS485 or open-loop).
  4. Mechanical design. Housing, busbars, potting, mounting points, connector and IP rating.
  5. Quotation. Unit price at your volumes, sample cost, tooling if any, and confirmed lead time.
  6. Sample build and validation. Assembled and bench tested in about two weeks, then shipped with UN38.3 documentation.

What we need from you

  • Nominal voltage and capacity (Ah or kWh)
  • Continuous and peak discharge current
  • Charge voltage and maximum charge current
  • Maximum dimensions or a drawing of the available space
  • Connector type and pin-out, or a sample of the existing pack
  • Communication protocol, if the host device talks to the BMS
  • IP rating, vibration and temperature requirements
  • Target cycle life and annual volume

If you only know half of this, send what you have. Most projects start from a photo of the existing pack plus the motor controller rating.

The more useful version of this list is a duty cycle: continuous and peak current, hours per charge, voltage and the lowest temperature in service. If you do not have those yet, how to size a battery pack walks through the calculation in four steps.

MOQ, samples and lead time

  • MOQ: 3 units for prototype and sample builds.
  • Sample lead time: about 2 weeks from a confirmed specification, including bench testing.
  • Repeat production: quoted per project, with lead time confirmed against cell availability at the time of order.
  • Tooling: standard housings need none; bespoke enclosures are quoted separately and only when required.

If you would rather inspect the line before committing, our factory audit checklist lists the eight things to check on the floor, the documents to request in advance, and the red flags that should end the conversation.

Before you approve a sample, it is worth knowing what to measure and how to read the datasheet in front of you. Both are covered in our battery buyer guides: how to read a specification sheet, and how to run a sample approval and incoming inspection.

What moves the price of a custom pack

Buyers often ask why two quotes for ‘the same’ 48V pack differ by 30%. These are the variables that actually drive unit cost:

  • Cell choice – brand, format and grade. A grade-A automotive cell costs more than a surplus or B-grade cell and behaves very differently after 500 cycles.
  • Capacity and current – more amp-hours means more cells; a higher continuous current means heavier busbars, a beefier BMS and better thermal paths.
  • Enclosure – a standard case costs little; a bespoke housing with tooling, potting and a high IP rating adds both tooling cost and lead time.
  • BMS and firmware – open-loop protection is cheap; closed-loop CAN communication with custom parameters takes engineering time.
  • Certification – UN38.3, MSDS, CE and IEC 62133 are included; extra market approvals are quoted separately.
  • Quantity – set-up, testing and documentation are fixed costs, so the unit price falls as the run gets longer.

After the sample

  1. You fit and test the sample in your vehicle or enclosure.
  2. We review your feedback – range, temperature, fit, connector, firmware behaviour.
  3. Revisions are made and, if needed, a second sample is built.
  4. The design is frozen and a production pilot run is scheduled.
  5. Production units are built to the frozen spec with the documentation agreed up front.

Before you commit to a production run, agree the warranty in writing: term, cycle limit, capacity threshold, exclusions and the claim process. Our battery warranty terms are published so you can compare them with other suppliers before you order.

Approval should be a written record, not a message. Battery sample approval and incoming inspection sets out what to test when the sample arrives, what to keep on file, and how to inspect the production batch against it.

Certification and transport

Samples and production packs ship with UN38.3 test summary, MSDS, CE declaration of conformity and IEC 62133 documentation for the cells and packs. Lithium batteries travel as dangerous goods class 9 (UN3480 or UN3481) and are declared under HS code 8507.60. We ship by sea, air and rail from China and will quote the Incoterm you prefer.

For the physical side of transport — UN specification boxes, the lithium battery mark, state of charge and pallet checks — read how lithium batteries are packed for export. It is worth agreeing at order stage, because state of charge is a production decision.

Your design stays yours

Drawings, firmware parameters and test data from your project are not reused for other customers. If you need an NDA before sending a specification, ask for one at the enquiry stage and we will sign it.

Frequently asked questions

Can you copy a pack we already buy?

Usually yes. Send the pack or detailed photos with connector, pin-out and protocol, and we will quote an equivalent – often with better cell matching and a stronger BMS.

What does a sample cost?

Samples are quoted at a small-build price, which is higher per unit than volume pricing because of set-up time. The sample cost is credited against the first production order in most projects – ask us to confirm for yours.

Is 3 units really enough for a prototype?

It is enough to validate fit, range and thermal behaviour in your vehicle or enclosure. For field trials across several units you will want more, and we will quote that volume.

Do you build storage packs as well as vehicle packs?

Yes – see our home energy storage batteries and the Battery Pack range.

How do we start?

Send the spec to sales@dididede.com or message WhatsApp. You will get a configuration proposal and a price, normally within one business day.

Start your project

Send us your specification or a photo of the pack you want to replace. Request a quote or message us on WhatsApp.

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