Start a custom power bank project by locking the use case, destination market and measurable product specification before discussing the logo. Define capacity in mAh and Wh, output/input profiles, ports, size, weight, cable arrangement, display, housing, packaging and required documents. Approve one exact sample and bill of materials before mass production; artwork alone does not make two power banks equivalent.
Define the User, Use Case and Destination Market
A trade-show giveaway, employee travel kit, retail private-label product and high-power laptop pack need different capacity, output, weight, documentation and packaging. Record who will use it, which devices it should charge, whether it must fit a pocket or bag, expected daily use, destination markets, sales channel, target quantity and delivery schedule.
Do not begin with a universal “best” capacity. A larger battery adds energy but also affects weight, size, recharge time and transport planning. Make these tradeoffs explicit in the brief.
Build One Specification That Every Supplier Must Quote
| Field | Record | Why it matters |
|---|---|---|
| Battery | Rated mAh, nominal voltage and Wh | Energy and label comparison |
| USB input/output | Connector, fixed PDO/PPS ranges where applicable, per-port and combined limits | Device compatibility and multi-port allocation |
| Physical design | Dimensions, weight, housing, display, button and built-in cables | Portability and tooling scope |
| Branding | Artwork file, process, color reference and print area | Repeatable appearance |
| Documents | Exact market, model and required declarations/test files | Claim and shipment review |
| Production consistency | Approved sample, defect limits, inspection and change review | Production consistency |
Separate Rated Energy from Usable Output
Convert the cell rating with Wh = mAh × nominal voltage ÷ 1000. The mAh-to-Wh calculator provides the formula and common examples. Wh is not the same as energy delivered to a phone because the power bank and receiving device each perform voltage conversion and consume energy.
If a supplier makes a charge-count or output-energy claim, require the test voltage, load, cutoff condition, cable/port, environment and sample identification. For USB Power Delivery, record the actual declared power profiles; a USB-C connector or a maximum wattage printed on the housing does not prove every voltage, PPS range or multi-port combination.
Keep Mandatory Information Clear after Customization
Logo placement, color, finish and packaging should not obscure ratings, warnings, model identification or other information required for the destination market. Approve artwork at actual size and compare it on the intended housing material, because texture, curvature and coating can change legibility and color.
If the pack will be carried on aircraft, make its Wh rating easy to identify and check current airline, route and jurisdiction rules. Do not convert a generic travel statement into a guarantee for every carrier.
Approve the Exact Sample, BOM and Test Record
- Review an engineering or pre-production sample against the written specification.
- Record the model, firmware if applicable, cell/PCB/BOM revision and artwork version.
- Test the required ports and power profiles with representative devices and loads.
- Compare measured weight, dimensions, Wh label and user-interface behavior.
- Approve packaging and documents for the exact destination market.
- Require written approval before critical component, supplier or artwork changes.
Compare Quotations on the Same Scope
Unit price is not comparable when one quote excludes tooling, branded packaging, test documents, freight, inspection or replacement terms. Use the same specification, quantity tiers, Incoterm, packaging configuration and approval requirements for every supplier. The mobile accessories wholesale guide covers supplier scorecards, samples and incoming inspection across a wider assortment.